From 6c714c8b08907658b018b760fbdb2ff97b7a2903 Mon Sep 17 00:00:00 2001 From: Renat Nurgaliyev Date: Sat, 23 May 2026 00:50:01 +0200 Subject: [PATCH] Add explanations for A* questions Automatically generated using Codex and GPT 5.5 in high reasoning mode and Claude Code with Opus 4.7 in high reasoning mode, models cross checking each other --- explanations.json | 2448 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 2448 insertions(+) diff --git a/explanations.json b/explanations.json index e87776f..7b1abd9 100644 --- a/explanations.json +++ b/explanations.json @@ -1,4 +1,2452 @@ { + "AA101": { + "revision": 1, + "explanation": "Impedance is the AC form of resistance, including resistive and reactive parts, so it is measured in ohms just like resistance.", + "source": "https://50ohm.de/A_spule_2.html", + "confidence": 8 + }, + "AA102": { + "revision": 1, + "explanation": "Charge is current integrated over time; one coulomb is one ampere-second, so As is the practical unit here.", + "source": "https://50ohm.de/EA_ladung_energie.html", + "confidence": 8 + }, + "AA103": { + "revision": 1, + "explanation": "Energy is power over time, so it can be expressed as joules in SI terms or as watt-hours in practical electrical use.", + "source": "https://50ohm.de/EA_ladung_energie.html", + "confidence": 8 + }, + "AA104": { + "revision": 1, + "explanation": "Symbol rate counts transmitted symbols per second, and that rate is measured in baud.", + "source": "https://50ohm.de/NEA_datenuebertragungsdrate.html", + "confidence": 8 + }, + "AA105": { + "revision": 1, + "explanation": "For power ratios, gain in dB is 10 log10(P2/P1); 10 log10(40) is about 16 dB.", + "source": "https://50ohm.de/A_dezibel_2.html", + "confidence": 8 + }, + "AA106": { + "revision": 1, + "explanation": "A 16 dB power gain is approximately 40 times; with 1 W drive the output is about 40 W, below the 100 W maximum.", + "source": "https://50ohm.de/A_dezibel_2.html", + "confidence": 8 + }, + "AA107": { + "revision": 1, + "explanation": "1 W is 0 dBW, and a 10 dB amplifier raises the power level by 10 dB, giving 10 dBW.", + "source": "https://50ohm.de/A_dezibel_2.html", + "confidence": 8 + }, + "AA108": { + "revision": 1, + "explanation": "dBW is referenced to 1 W, so 20 dBW means 10^(20/10) W = 100 W = 10^2 W.", + "source": "https://50ohm.de/A_dezibel_2.html", + "confidence": 8 + }, + "AA109": { + "revision": 1, + "explanation": "The amplifier output is 10 W; in dBm that is 10 W = 10000 mW, and 10 log10(10000) = 40 dBm.", + "source": "https://50ohm.de/A_dezibel_2.html", + "confidence": 8 + }, + "AA110": { + "revision": 1, + "explanation": "dBm is referenced to 1 mW: 0 dBm is 1 mW, +3 dB is about double or 2 mW, and +20 dB is 100 times or 100 mW.", + "source": "https://50ohm.de/A_dezibel_2.html", + "confidence": 8 + }, + "AA111": { + "revision": 1, + "explanation": "For voltage ratios use 20 log10(U2/U1); 20 log10(15) is about 23.5 dB.", + "source": "https://50ohm.de/A_dezibel_2.html", + "confidence": 8 + }, + "AA112": { + "revision": 1, + "explanation": "120 dB relative to 1 microvolt per meter is a voltage ratio of 10^(120/20) = 10^6, so the field is 1 V/m.", + "source": "https://50ohm.de/A_dezibel_2.html", + "confidence": 8 + }, + "AA113": { + "revision": 1, + "explanation": "Each S-step is 6 dB; S4 to S7 is three steps, so 3 x 6 dB = 18 dB.", + "source": "https://50ohm.de/NEA_s_meter.html", + "confidence": 8 + }, + "AA114": { + "revision": 1, + "explanation": "From S9+20 dB down to S9 removes 20 dB, and from S9 to S8 removes another 6 dB, totaling 26 dB.", + "source": "https://50ohm.de/NEA_s_meter.html", + "confidence": 8 + }, + "AA115": { + "revision": 1, + "explanation": "1 ppm is one part in one million; 435 MHz divided by 10^6 is 435 Hz.", + "source": "https://50ohm.de/A_frequenzgenauigkeit.html", + "confidence": 8 + }, + "AA116": { + "revision": 1, + "explanation": "10 ppm at 14.200000 MHz is 14.2 MHz x 10/10^6 = 142 Hz, so the possible frequency is 14.200000 MHz plus or minus 0.000142 MHz.", + "source": "https://50ohm.de/A_frequenzgenauigkeit.html", + "confidence": 8 + }, + "AB101": { + "revision": 1, + "explanation": "Use $R = rho l/A$ with copper $rho = 0.018 ohm mm2/m$ and $A = pi(0.1 mm)^2 = 0.0314 mm2$; $0.018 x 1.8 / 0.0314$ is about 1.02 ohm.", + "source": "https://50ohm.de/EA_leiterwiderstand.html", + "confidence": 8 + }, + "AB102": { + "revision": 1, + "explanation": "Rearrange $R = rho l/A$ to $l = RA/rho$; $1.5 ohm x 0.5 mm2 / 0.018 ohm mm2/m$ is about 41.7 m.", + "source": "https://50ohm.de/EA_leiterwiderstand.html", + "confidence": 8 + }, + "AB103": { + "revision": 1, + "explanation": "In metals, higher temperature increases lattice vibration and electron scattering, so resistance normally rises with a positive temperature coefficient.", + "source": "https://50ohm.de/EA_leiterwiderstand.html", + "confidence": 8 + }, + "AB104": { + "revision": 1, + "explanation": "Semiconductors such as silicon are poor conductors when pure, but heat or small amounts of dopant atoms can provide mobile charge carriers.", + "source": "https://50ohm.de/A_halbleiter_2.html", + "confidence": 8 + }, + "AB105": { + "revision": 1, + "explanation": "Doping means deliberately adding atoms with different valence to a semiconductor so extra electrons or holes become available as charge carriers.", + "source": "https://50ohm.de/A_halbleiter_2.html", + "confidence": 8 + }, + "AB106": { + "revision": 1, + "explanation": "N-type material is doped to have extra mobile electrons; electrons are the majority carriers.", + "source": "https://50ohm.de/A_halbleiter_2.html", + "confidence": 8 + }, + "AB107": { + "revision": 1, + "explanation": "P-type material is doped to create mobile holes; holes are the majority carriers.", + "source": "https://50ohm.de/A_halbleiter_2.html", + "confidence": 8 + }, + "AB108": { + "revision": 1, + "explanation": "At the PN junction, electrons diffuse from the N side and recombine with holes on the P side, leaving a depleted insulating region at the boundary.", + "source": "https://50ohm.de/A_halbleiter_2.html", + "confidence": 7 + }, + "AB109": { + "revision": 1, + "explanation": "The shown polarity reverse-biases the diode, pulling majority carriers away from the junction, so the depletion region widens.", + "source": "https://50ohm.de/NEA_halbleiter_2.html", + "confidence": 7 + }, + "AB201": { + "revision": 1, + "explanation": "A voltage source should hold voltage constant, which requires low internal resistance; a current source should hold current constant, which requires high internal resistance.", + "source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html", + "confidence": 8 + }, + "AB202": { + "revision": 1, + "explanation": "Maximum power transfer occurs when the load resistance equals the source internal resistance.", + "source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html", + "confidence": 8 + }, + "AB203": { + "revision": 1, + "explanation": "Voltage matching minimizes voltage drop inside the source, so the load resistance must be much larger than the source internal resistance.", + "source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html", + "confidence": 8 + }, + "AB204": { + "revision": 1, + "explanation": "Current matching uses a source whose internal resistance is much larger than the load, so the load current stays nearly constant.", + "source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html", + "confidence": 8 + }, + "AB205": { + "revision": 1, + "explanation": "The load current is $4.8 V / 1.2 ohm = 4 A$ and the source drops 0.2 V internally, so $R_i = 0.2 V / 4 A = 0.05 ohm$.", + "source": "https://50ohm.de/EA_innenwiderstand.html", + "confidence": 8 + }, + "AB206": { + "revision": 1, + "explanation": "The internal voltage drop is $13.5 V - 12.4 V = 1.1 V$; dividing by 0.9 A gives about 1.22 ohm.", + "source": "https://50ohm.de/EA_innenwiderstand.html", + "confidence": 8 + }, + "AB207": { + "revision": 1, + "explanation": "The terminal voltage falls by 0.5 V at 2 A, so $R_i = 0.5 V / 2 A = 0.25 ohm$.", + "source": "https://50ohm.de/EA_innenwiderstand.html", + "confidence": 8 + }, + "AB208": { + "revision": 1, + "explanation": "The voltage drop is 0.2 V at 20 A, so $R_i = 0.2 V / 20 A = 0.01 ohm = 10 milliohm$.", + "source": "https://50ohm.de/EA_innenwiderstand.html", + "confidence": 8 + }, + "AB209": { + "revision": 1, + "explanation": "The six 2 V cells are in series, so voltages add to 12 V while the ampere-hour capacity remains that of one cell, 10 Ah.", + "source": "https://50ohm.de/A_akku.html", + "confidence": 7 + }, + "AB210": { + "revision": 1, + "explanation": "The mAh value on an accumulator pack states how much charge it can nominally deliver, so it is the nominal capacity.", + "source": "https://50ohm.de/A_akku.html", + "confidence": 8 + }, + "AB211": { + "revision": 1, + "explanation": "Discharging only down to 10 percent leaves 90 percent usable: $0.9 x 60 Ah = 54 Ah$; $54 Ah / 0.8 A = 67.5 h$.", + "source": "https://50ohm.de/A_akku.html", + "confidence": 8 + }, + "AB212": { + "revision": 1, + "explanation": "A solar cell converts incident light or other radiation energy directly into electrical energy by freeing charge carriers.", + "source": "https://50ohm.de/EA_photovoltaik.html", + "confidence": 8 + }, + "AB213": { + "revision": 1, + "explanation": "Input power is $12 V x 2 A = 24 W$ and output power is $5 V x 3 A = 15 W$; efficiency is $15/24 = 62.5%$.", + "source": "https://50ohm.de/NEA_spannungswandler.html", + "confidence": 8 + }, + "AB214": { + "revision": 1, + "explanation": "Input power is $5 V x 3 A = 15 W$ and output power is $12 V x 1 A = 12 W$; efficiency is $12/15 = 80%$.", + "source": "https://50ohm.de/NEA_spannungswandler.html", + "confidence": 8 + }, + "AB301": { + "revision": 1, + "explanation": "For a sine current, $I_eff = I_max / sqrt(2)$; power is $I_eff^2 R = (0.5/sqrt(2))^2 x 20 = 2.5 W$.", + "source": "https://50ohm.de/EA_wechselstrom_leistung.html", + "confidence": 8 + }, + "AB302": { + "revision": 1, + "explanation": "Point X3 is three quarters of a cycle after zero, which is 270 degrees or $3 pi / 2$ radians.", + "source": "https://50ohm.de/NEA_slide_nea_bauelemente.html", + "confidence": 7 + }, + "AB303": { + "revision": 1, + "explanation": "The two sine waves are shifted by one eighth of a full cycle; $360 degrees / 8 = 45 degrees$.", + "source": "https://50ohm.de/NEA_slide_nea_bauelemente.html", + "confidence": 7 + }, + "AB401": { + "revision": 2, + "explanation": "Harmonics are integer multiples of a fundamental frequency: first harmonic is the fundamental, second is twice it, and so on.", + "source": "https://50ohm.de/A_slide_a_sender.html", + "confidence": 8 + }, + "AB402": { + "revision": 2, + "explanation": "The first overtone is the second harmonic, so the third overtone is one step higher again: the fourth harmonic.", + "source": "https://50ohm.de/A_slide_a_sender.html", + "confidence": 8 + }, + "AB403": { + "revision": 2, + "explanation": "A non-sinusoidal periodic waveform can be decomposed into its fundamental plus integer-multiple overtones.", + "source": "https://50ohm.de/A_slide_a_sender.html", + "confidence": 7 + }, + "AB404": { + "revision": 1, + "explanation": "An ideal sine wave has only one spectral line at its fundamental frequency, so the matching spectrum contains a single component.", + "source": "https://50ohm.de/NEA_fourier_transformation.html", + "confidence": 7 + }, + "AB405": { + "revision": 1, + "explanation": "A non-sinusoidal periodic signal has a fundamental plus harmonic lines, so the matching spectrum shows multiple discrete components at integer multiples.", + "source": "https://50ohm.de/NEA_fourier_transformation.html", + "confidence": 7 + }, + "AB406": { + "revision": 1, + "explanation": "A spectrum with only one line corresponds to a pure sinusoidal time-domain signal.", + "source": "https://50ohm.de/NEA_fourier_transformation.html", + "confidence": 7 + }, + "AB407": { + "revision": 1, + "explanation": "The shown harmonic spectrum corresponds to the periodic non-sinusoidal waveform whose components line up with those harmonic amplitudes.", + "source": "https://50ohm.de/NEA_fourier_transformation.html", + "confidence": 7 + }, + "AB408": { + "revision": 1, + "explanation": "White noise has roughly constant power per hertz, so the total received noise power is proportional to receiver bandwidth.", + "source": "https://50ohm.de/A_rauschen.html", + "confidence": 8 + }, + "AB409": { + "revision": 1, + "explanation": "Noise power scales with bandwidth; changing from 2.5 kHz to 0.5 kHz is a factor of 5 reduction, and 10 log10(5) is about 7 dB.", + "source": "https://50ohm.de/A_rauschen.html", + "confidence": 8 + }, + "AB501": { + "revision": 1, + "explanation": "Stored energy in watt-hours is voltage times ampere-hour capacity: $12 V x 5 Ah = 60 Wh$.", + "source": "https://50ohm.de/A_akku.html", + "confidence": 8 + }, + "AB502": { + "revision": 1, + "explanation": "Power is $230 V x 0.63 A = 144.9 W$; over 7 h this is $144.9 W x 7 h = 1014 Wh$, about 1.01 kWh.", + "source": "https://50ohm.de/EA_ladung_energie.html", + "confidence": 8 + }, + "AB503": { + "revision": 1, + "explanation": "The resistor has $P = U^2/R = 10^2/100 = 1 W$; over one hour that is 1 Wh, equal to 3600 J.", + "source": "https://50ohm.de/EA_ladung_energie.html", + "confidence": 7 + }, + "AB601": { + "revision": 1, + "explanation": "In metal conductors the physical current direction is the electron motion, from the negative pole toward the positive pole, opposite conventional current.", + "source": "https://50ohm.de/NEA_physikalische_stromrichtung.html", + "confidence": 7 + }, + "AC101": { + "revision": 1, + "explanation": "In an ideal capacitor the current is proportional to the rate of voltage change, so current reaches its extrema a quarter cycle before voltage: it leads by 90 degrees.", + "source": "https://50ohm.de/A_kondensator_2.html", + "confidence": 8 + }, + "AC102": { + "revision": 1, + "explanation": "Capacitive reactance is negative in AC sign convention, and its magnitude is $1/(2 pi f C)$, so it depends on frequency and capacitance.", + "source": "https://50ohm.de/NEA_kondensator_2.html", + "confidence": 8 + }, + "AC103": { + "revision": 1, + "explanation": "A pure reactance stores and returns energy instead of converting it to heat, so the ideal reactive resistance has no heat loss.", + "source": "https://50ohm.de/A_kondensator_2.html", + "confidence": 8 + }, + "AC104": { + "revision": 1, + "explanation": "Use $X_C = 1/(2 pi f C)$; with 100 MHz and 10 pF this gives about 159 ohm.", + "source": "https://50ohm.de/NEA_kondensator_2.html", + "confidence": 8 + }, + "AC105": { + "revision": 1, + "explanation": "Use $X_C = 1/(2 pi f C)$; with 145 MHz and 50 pF this is about 22 ohm.", + "source": "https://50ohm.de/NEA_kondensator_2.html", + "confidence": 8 + }, + "AC106": { + "revision": 1, + "explanation": "Use $X_C = 1/(2 pi f C)$; with 100 MHz and 100 pF this gives about 15.9 ohm.", + "source": "https://50ohm.de/NEA_kondensator_2.html", + "confidence": 8 + }, + "AC107": { + "revision": 1, + "explanation": "Use $X_C = 1/(2 pi f C)$; with 435 MHz and 100 pF this gives about 3.7 ohm.", + "source": "https://50ohm.de/NEA_kondensator_2.html", + "confidence": 8 + }, + "AC108": { + "revision": 1, + "explanation": "First find reactance from $X_C = U/I = 16 V / 0.032 A = 500 ohm$; then $C = 1/(2 pi f X_C)$ gives about 6.37 microfarad.", + "source": "https://50ohm.de/NEA_kondensator_2.html", + "confidence": 8 + }, + "AC109": { + "revision": 1, + "explanation": "Real capacitors are not ideal: dielectric loss and lead or ESR losses convert some energy into heat under AC operation.", + "source": "https://50ohm.de/EA_kondensator_2.html", + "confidence": 8 + }, + "AC110": { + "revision": 1, + "explanation": "Capacitor loss is commonly described by loss factor tan delta; high loss means low quality factor, with tan delta equal to the reciprocal of Q.", + "source": "https://50ohm.de/EA_kondensator_2.html", + "confidence": 8 + }, + "AC111": { + "revision": 1, + "explanation": "An ideal capacitor draws reactive current but no real power in steady-state AC, so the real power is approximately zero.", + "source": "https://50ohm.de/A_kondensator_2.html", + "confidence": 8 + }, + "AC201": { + "revision": 1, + "explanation": "In an ideal inductor the magnetic field opposes current changes, so current lags the applied voltage by 90 degrees.", + "source": "https://50ohm.de/A_spule_2.html", + "confidence": 8 + }, + "AC202": { + "revision": 1, + "explanation": "Inductive reactance is positive in AC sign convention and has magnitude $X_L = 2 pi f L$, so it depends on frequency and inductance.", + "source": "https://50ohm.de/A_spule_2.html", + "confidence": 8 + }, + "AC203": { + "revision": 1, + "explanation": "With DC only the winding resistance limits current; with AC the inductive reactance is added, so the total impedance is higher and current is smaller.", + "source": "https://50ohm.de/A_spule_2.html", + "confidence": 8 + }, + "AC204": { + "revision": 1, + "explanation": "Use $X_L = 2 pi f L$; $2 pi x 100 MHz x 3 microhenry$ is about 1885 ohm.", + "source": "https://50ohm.de/A_spule_2.html", + "confidence": 8 + }, + "AC205": { + "revision": 1, + "explanation": "For a core with AL value, $L = N^2 x AL$; $14^2 x 1.5 nH = 294 nH = 0.294 microhenry$.", + "source": "https://50ohm.de/A_spule_2.html", + "confidence": 8 + }, + "AC206": { + "revision": 1, + "explanation": "Use $L = N^2 x AL$; $300^2 x 1250 nH = 112500000 nH = 112.5 mH$.", + "source": "https://50ohm.de/A_spule_2.html", + "confidence": 8 + }, + "AC207": { + "revision": 1, + "explanation": "Rearrange to $N = sqrt(L/AL)$; $sqrt(2 mH / 250 nH) = sqrt(8000)$, about 89 turns.", + "source": "https://50ohm.de/A_spule_2.html", + "confidence": 8 + }, + "AC208": { + "revision": 1, + "explanation": "Rearrange to $N = sqrt(L/AL)$; $sqrt(12 microhenry / 30 nH) = sqrt(400) = 20 turns$.", + "source": "https://50ohm.de/A_spule_2.html", + "confidence": 8 + }, + "AC209": { + "revision": 1, + "explanation": "Coil losses are represented by an equivalent series resistance; the loss factor tan delta is used and equals the reciprocal of the quality factor Q.", + "source": "https://50ohm.de/A_spule_2.html", + "confidence": 8 + }, + "AC210": { + "revision": 1, + "explanation": "A conductive metal enclosure shields the electric field around the tuned-circuit coil and reduces unwanted radiation from it.", + "source": "https://50ohm.de/A_spule_2.html", + "confidence": 8 + }, + "AC211": { + "revision": 1, + "explanation": "A choke core is normally ferrite because ferrite gives high magnetic permeability and high RF loss for unwanted common-mode currents.", + "source": "https://50ohm.de/A_spule_2.html", + "confidence": 7 + }, + "AC301": { + "revision": 1, + "explanation": "Mutual induction needs a changing magnetic field, so a changing current in a magnetically coupled neighboring coil induces voltage in the other coil.", + "source": "https://50ohm.de/A_uebertrager_2.html", + "confidence": 8 + }, + "AC302": { + "revision": 1, + "explanation": "With losses neglected, primary and secondary power are equal: $6 V x 1.15 A = 6.9 W$, and $6.9 W / 230 V = 0.030 A$.", + "source": "https://50ohm.de/A_uebertrager_2.html", + "confidence": 8 + }, + "AC303": { + "revision": 1, + "explanation": "Impedance transforms with the square of the turns ratio; with 1:4, the input sees $16 kOhm / 4^2 = 1 kOhm$.", + "source": "https://50ohm.de/A_uebertrager_2.html", + "confidence": 7 + }, + "AC304": { + "revision": 1, + "explanation": "The same 1:4 transformer reflects the secondary load by a factor of 16, so $6.4 kOhm / 16 = 0.4 kOhm$ at a-b.", + "source": "https://50ohm.de/A_uebertrager_2.html", + "confidence": 7 + }, + "AC305": { + "revision": 1, + "explanation": "The impedance ratio is $450/50 = 9$; turns ratio is the square root of impedance ratio, so $sqrt(9) = 3$.", + "source": "https://50ohm.de/A_uebertrager_2.html", + "confidence": 8 + }, + "AC306": { + "revision": 1, + "explanation": "A 2.5 kOhm load against 50 ohm is about a 50:1 impedance ratio, close to 49:1, so the turns ratio is about 1:7.", + "source": "https://50ohm.de/A_uebertrager_2.html", + "confidence": 8 + }, + "AC307": { + "revision": 1, + "explanation": "The wire area is $pi d^2/4 = pi x 0.5^2/4 = 0.196 mm2$; at 2.5 A/mm2 the current is about 0.49 A.", + "source": "https://50ohm.de/A_uebertrager_2.html", + "confidence": 8 + }, + "AC401": { + "revision": 1, + "explanation": "In forward bias, the depletion region is reduced and electrons can cross the PN junction from the N side to the P side.", + "source": "https://50ohm.de/A_diode_2.html", + "confidence": 8 + }, + "AC402": { + "revision": 1, + "explanation": "Electrons are the majority carriers in the N region, and in forward operation they move across the junction into the P region.", + "source": "https://50ohm.de/A_diode_2.html", + "confidence": 8 + }, + "AC403": { + "revision": 1, + "explanation": "As temperature rises, diode saturation current increases, so the forward voltage needed for a given current falls.", + "source": "https://50ohm.de/A_diode_2.html", + "confidence": 8 + }, + "AC404": { + "revision": 1, + "explanation": "A varicap is reverse-biased; lower reverse voltage makes the depletion region narrower, which increases junction capacitance.", + "source": "https://50ohm.de/A_diode_2.html", + "confidence": 8 + }, + "AC405": { + "revision": 1, + "explanation": "Antiparallel silicon diodes clip the waveform when either polarity exceeds about 0.6 V, so the output is the sine wave limited at that threshold.", + "source": "https://50ohm.de/A_diode_2.html", + "confidence": 7 + }, + "AC406": { + "revision": 1, + "explanation": "Germanium diodes have a lower threshold, about 0.3 V, so the same limiter clips the waveform earlier and more strongly than silicon diodes.", + "source": "https://50ohm.de/A_diode_2.html", + "confidence": 7 + }, + "AC407": { + "revision": 1, + "explanation": "A photodiode generates electron-hole pairs when illuminated and can produce photocurrent from light.", + "source": "https://50ohm.de/A_diode_2.html", + "confidence": 8 + }, + "AC408": { + "revision": 1, + "explanation": "An optocoupler transfers a signal optically between an LED and a photosensitive device, giving galvanic isolation between the two circuits.", + "source": "https://50ohm.de/A_diode_2.html", + "confidence": 8 + }, + "AC501": { + "revision": 1, + "explanation": "In a bipolar transistor, a small base current controls a larger collector current, so it is current-controlled.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 8 + }, + "AC502": { + "revision": 1, + "explanation": "A field-effect transistor controls channel current by the electric field from the gate-source voltage, so it is voltage-controlled.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 8 + }, + "AC503": { + "revision": 1, + "explanation": "An NPN transistor has an N emitter, P base, and N collector, so the p-doped region is the base.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 8 + }, + "AC504": { + "revision": 1, + "explanation": "A PNP transistor has a P emitter, N base, and P collector, so the n-doped region is the base.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 8 + }, + "AC505": { + "revision": 1, + "explanation": "For a bipolar transistor to conduct normally, the base-emitter junction is forward biased.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 8 + }, + "AC506": { + "revision": 1, + "explanation": "The symbol shows a gate controlling a channel between source and drain, which identifies a field-effect transistor.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC507": { + "revision": 1, + "explanation": "The continuous channel marks depletion-mode, self-conducting JFETs; the arrow direction distinguishes N-channel from P-channel in the two symbols.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC508": { + "revision": 1, + "explanation": "The insulated gate identifies a MOSFET, the interrupted channel marks enhancement mode, and the arrow/channel orientation identifies an N-channel device.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC509": { + "revision": 1, + "explanation": "The correct symbol combines an insulated gate, interrupted enhancement-mode channel, and N-channel arrow orientation.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC510": { + "revision": 1, + "explanation": "A depletion-mode N-channel MOSFET is recognized by the insulated gate plus continuous channel and N-channel arrow orientation.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC511": { + "revision": 1, + "explanation": "A depletion-mode P-channel MOSFET has the insulated gate, continuous channel, and the P-channel arrow orientation.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC512": { + "revision": 1, + "explanation": "FET terminals are named drain, gate, and source; emitter, base, and collector are bipolar-transistor names.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 8 + }, + "AC513": { + "revision": 1, + "explanation": "The shown FET package labels the channel terminals as drain and source, with the control terminal as gate.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC514": { + "revision": 1, + "explanation": "The gate-source voltage changes the channel resistance between source and drain, thereby controlling drain current with almost no gate current.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 8 + }, + "AC515": { + "revision": 1, + "explanation": "Base current is $5 mA / 298 = 16.8 microampere$; with about 0.6 V base-emitter drop, $R_1 = (12 - 0.6) V / 16.8 microampere$, about 680 kOhm.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC516": { + "revision": 1, + "explanation": "Making the divider current much larger than base current keeps the base voltage mostly set by the divider, so transistor beta and temperature changes disturb the operating point less.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC517": { + "revision": 1, + "explanation": "Base current is $2 mA/200 = 10 microampere$; R2 carries ten times that, so R1 carries 110 microampere. With 1 V at the emitter, the base is about 1.6 V, giving $R_1 = 8.4 V/110 microampere = 76.4 kOhm$.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC518": { + "revision": 1, + "explanation": "Base current is 10 microampere and R2 current is 100 microampere, so R1 current is 110 microampere; with the base near 0.6 V, $R_1 = 9.4 V/110 microampere = 85.5 kOhm$.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC519": { + "revision": 1, + "explanation": "If R1 is open, the base receives no forward bias, the transistor switches off, and with no collector current the collector rises to the supply voltage.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC520": { + "revision": 1, + "explanation": "If R2 is open, the base is driven too strongly through R1, so the transistor saturates; collector current is then limited mainly by RC and collector voltage falls near saturation voltage.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC521": { + "revision": 1, + "explanation": "The gate draws negligible current, so the divider gives $U_G = 44 V x 1 kOhm/(10 kOhm + 1 kOhm) = 4 V$; with the source at reference, that is $U_GS$.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC522": { + "revision": 1, + "explanation": "For a divider, $R_2 = R_1 U_G/(U_B - U_G)$; $10 kOhm x 2.8/(44 - 2.8)$ gives about 680 ohm.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC523": { + "revision": 1, + "explanation": "Conduction loss is $P = I^2 R$; $25^2 x 0.004 ohm = 2.5 W$.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 8 + }, + "AC524": { + "revision": 1, + "explanation": "A flyback diode is placed antiparallel across the coil, reverse-biased during normal operation and forward-biased for the coil's turn-off current.", + "source": "https://50ohm.de/A_transistor_2.html", + "confidence": 7 + }, + "AC601": { + "revision": 2, + "explanation": "An integrated circuit combines many circuit elements directly on one semiconductor substrate.", + "source": "https://50ohm.de/A_integrierte_schaltkreise.html", + "confidence": 8 + }, + "AC602": { + "revision": 2, + "explanation": "An MMIC is monolithic, so active and passive microwave circuit elements are integrated on the same semiconductor substrate.", + "source": "https://50ohm.de/A_integrierte_schaltkreise.html", + "confidence": 8 + }, + "AC603": { + "revision": 2, + "explanation": "An MMIC amplifier integrates the active device and matching elements, giving broad bandwidth and useful gain with fewer external components.", + "source": "https://50ohm.de/A_integrierte_schaltkreise.html", + "confidence": 8 + }, + "AC604": { + "revision": 2, + "explanation": "Many MMICs are designed as RF building blocks with standard input and output impedances such as 50 ohm.", + "source": "https://50ohm.de/A_integrierte_schaltkreise.html", + "confidence": 8 + }, + "AD101": { + "revision": 1, + "explanation": "Series capacitors add by reciprocals: $1/C = 1/100 pF + 1/47 pF + 1/22 pF$, giving about 13.0 pF.", + "source": "https://50ohm.de/A_reihe_parallel_gemischt.html", + "confidence": 8 + }, + "AD102": { + "revision": 1, + "explanation": "Series inductances add directly: 2200 nH is 2.2 microhenry, 0.033 mH is 33 microhenry, so the sum is 2.2 + 33 + 150 = 185.2 microhenry.", + "source": "https://50ohm.de/A_reihe_parallel_gemischt.html", + "confidence": 8 + }, + "AD103": { + "revision": 1, + "explanation": "The shown capacitances are effectively parallel, so they add: 100 pF + 1500 pF + 220 pF + 1 pF = 1821 pF.", + "source": "https://50ohm.de/A_reihe_parallel_gemischt.html", + "confidence": 7 + }, + "AD104": { + "revision": 1, + "explanation": "At 1 MHz and 1 nF, $X_C$ is about 159 ohm; the series impedance magnitude is $sqrt(100^2 + 159^2)$, about 188 ohm.", + "source": "https://50ohm.de/A_reihe_parallel_gemischt.html", + "confidence": 8 + }, + "AD105": { + "revision": 1, + "explanation": "At 1 MHz and 100 microhenry, $X_L$ is about 628 ohm; $|Z| = sqrt(100^2 + 628^2)$, about 636 ohm.", + "source": "https://50ohm.de/A_reihe_parallel_gemischt.html", + "confidence": 8 + }, + "AD106": { + "revision": 1, + "explanation": "If 1 mA flows through R3, the parallel section has 10 V across it; R2 draws another 1 mA, so 2 mA through R1 drops 20 V, making the total 30 V.", + "source": "https://50ohm.de/EA_reihe_parallel_widerstandsnetz_2.html", + "confidence": 7 + }, + "AD107": { + "revision": 1, + "explanation": "R2 and R3 in parallel give 5 kOhm, in series with R1 gives 15 kOhm; 15 V / 15 kOhm is 1 mA total, split equally so R3 has 0.5 mA.", + "source": "https://50ohm.de/EA_reihe_parallel_widerstandsnetz_2.html", + "confidence": 7 + }, + "AD108": { + "revision": 1, + "explanation": "The total current is 1 mA, so the parallel section has 5 V across it; R2 power is $5^2/10000 = 0.0025 W = 2.5 mW$.", + "source": "https://50ohm.de/EA_reihe_parallel_widerstandsnetz_2.html", + "confidence": 7 + }, + "AD109": { + "revision": 1, + "explanation": "The input is 200 ohm plus 100 ohm in parallel with 200 ohm + R; at R = 0 this is about 267 ohm, and at R = 1 kOhm it is about 292 ohm.", + "source": "https://50ohm.de/NEA_slide_nea_reihen_parallelschaltung.html", + "confidence": 7 + }, + "AD110": { + "revision": 1, + "explanation": "Each side branch is 2.2 kOhm + 220 ohm = 2420 ohm, and two equal branches in parallel give half that value, 1210 ohm.", + "source": "https://50ohm.de/NEA_slide_nea_reihen_parallelschaltung.html", + "confidence": 7 + }, + "AD111": { + "revision": 1, + "explanation": "A bridge has zero branch voltage when the two divider ratios are equal, which gives $R1/R2 = R3/R4$.", + "source": "https://50ohm.de/EA_brueckenschaltung.html", + "confidence": 7 + }, + "AD112": { + "revision": 1, + "explanation": "All four resistors are equal, so the two divider midpoints sit at the same potential; the bridge voltage from A to B is 0 V.", + "source": "https://50ohm.de/EA_brueckenschaltung.html", + "confidence": 7 + }, + "AD113": { + "revision": 1, + "explanation": "The left divider gives point A at 10 V and the right divider gives point B at 1 V, so measured from A to B the bridge voltage is +9 V.", + "source": "https://50ohm.de/EA_brueckenschaltung.html", + "confidence": 7 + }, + "AD114": { + "revision": 1, + "explanation": "The load is parallel to R2: $2.2 kOhm || 8.2 kOhm$ is about 1.73 kOhm. The divider output is $12 V x 1.73/(10 + 1.73)$, about 1.8 V.", + "source": "https://50ohm.de/A_spannungsteiler_2.html", + "confidence": 7 + }, + "AD115": { + "revision": 1, + "explanation": "Adding the load lowers the effective lower resistance of the divider, increasing the supply current through R1; with higher current, R1 dissipates more heat.", + "source": "https://50ohm.de/A_spannungsteiler_2.html", + "confidence": 7 + }, + "AD201": { + "revision": 1, + "explanation": "An RC high-pass cutoff is $f_g = 1/(2 pi R C)$; with 4.7 kOhm and 2.2 nF this is about 15.4 kHz.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 7 + }, + "AD202": { + "revision": 1, + "explanation": "An RC low-pass has the same cutoff formula, $f_g = 1/(2 pi R C)$; with 10 kOhm and 47 nF this is about 339 Hz.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 7 + }, + "AD203": { + "revision": 1, + "explanation": "The relevant low-pass is R1 with C1; C2 is supply decoupling and the amplifier input is very high impedance. $1/(2 pi x 4.7 kOhm x 6.8 nF)$ is about 5 kHz.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 7 + }, + "AD204": { + "revision": 1, + "explanation": "A series resonant circuit has minimum impedance at resonance, while a parallel resonant circuit has maximum impedance there; the correct pairings match those curve shapes.", + "source": "https://50ohm.de/A_slide_a_grundlegende_schaltungen.html", + "confidence": 7 + }, + "AD205": { + "revision": 1, + "explanation": "The circuit passes only a middle range of frequencies while attenuating frequencies below and above that range, which is the behavior of a band-pass filter.", + "source": "https://50ohm.de/A_slide_a_grundlegende_schaltungen.html", + "confidence": 7 + }, + "AD206": { + "revision": 1, + "explanation": "At resonance, inductive and capacitive reactances have equal magnitude and opposite sign, so their reactive effects cancel.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 8 + }, + "AD207": { + "revision": 1, + "explanation": "In a series resonant circuit the L and C reactances cancel, leaving only the real series resistance R as the impedance.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 7 + }, + "AD208": { + "revision": 1, + "explanation": "Use Thomson's formula $f = 1/(2 pi sqrt(L C))$; with 1.2 microhenry and 6.8 pF the result is about 55.7 MHz.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 7 + }, + "AD209": { + "revision": 1, + "explanation": "The resistor does not set the ideal resonant frequency; $1/(2 pi sqrt(10 microhenry x 1 nF))$ is about 1.592 MHz.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 7 + }, + "AD210": { + "revision": 1, + "explanation": "Using $f = 1/(2 pi sqrt(L C))$ with 100 microhenry and 0.01 microfarad gives about 159 kHz.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 7 + }, + "AD211": { + "revision": 1, + "explanation": "For the parallel resonant circuit, $f = 1/(2 pi sqrt(2.2 microhenry x 56 pF))$, giving about 14.34 MHz.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 7 + }, + "AD212": { + "revision": 1, + "explanation": "The parallel capacitances add to about 1.82 nF; with 1.2 mH, $1/(2 pi sqrt(L C))$ gives about 107.7 kHz.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 7 + }, + "AD213": { + "revision": 1, + "explanation": "Resonant frequency is inversely proportional to $sqrt(L C)$, so using a smaller inductance raises the frequency.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 8 + }, + "AD214": { + "revision": 1, + "explanation": "Fewer turns reduce coil inductance, and lower inductance increases the resonant frequency.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 8 + }, + "AD215": { + "revision": 1, + "explanation": "Increasing capacitance increases the LC product, so the resonant frequency decreases.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 8 + }, + "AD216": { + "revision": 1, + "explanation": "Pushing the coil turns closer together increases inductance, and higher inductance lowers the resonant frequency.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 8 + }, + "AD217": { + "revision": 1, + "explanation": "A ferrite core increases coil inductance, and the larger L in the LC formula lowers the resonant frequency.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 8 + }, + "AD218": { + "revision": 1, + "explanation": "Moving the potentiometer toward X raises the reverse voltage on the varicap; higher reverse voltage lowers its capacitance, so the LC resonant frequency rises.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 7 + }, + "AD219": { + "revision": 1, + "explanation": "Bandwidth is read as the frequency difference between the two points on the curve at the specified level; at -60 dB the marked span is about 4 kHz.", + "source": "https://50ohm.de/A_slide_a_grundlegende_schaltungen.html", + "confidence": 7 + }, + "AD220": { + "revision": 1, + "explanation": "Filter bandwidth is the difference between the two frequencies where the voltage has fallen to 0.7 of the resonant maximum, the -3 dB points.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 8 + }, + "AD221": { + "revision": 1, + "explanation": "SSB speech typically needs about 2.4 to 2.7 kHz of filter bandwidth, so a 2.7 kHz crystal filter fits SSB operation.", + "source": "https://50ohm.de/A_slide_a_empfaenger.html", + "confidence": 8 + }, + "AD222": { + "revision": 1, + "explanation": "CW reception benefits from a narrow filter; 500 Hz is typical for separating Morse signals from nearby stations.", + "source": "https://50ohm.de/A_slide_a_empfaenger.html", + "confidence": 8 + }, + "AD223": { + "revision": 1, + "explanation": "For a series resonant circuit, bandwidth is $B = R/(2 pi L)$; $10/(2 pi x 100 microhenry)$ is about 15.9 kHz.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 8 + }, + "AD224": { + "revision": 1, + "explanation": "For the parallel case, $B = 1/(2 pi R C)$; with 1 kOhm and 56 pF this is about 2.84 MHz.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 8 + }, + "AD225": { + "revision": 1, + "explanation": "For the series circuit, Q is resonant frequency divided by bandwidth; about 159 kHz / 15.9 kHz = 10.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 8 + }, + "AD226": { + "revision": 1, + "explanation": "For the parallel circuit, Q is resonant frequency divided by bandwidth; about 14.34 MHz / 2.84 MHz is about 5.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 8 + }, + "AD227": { + "revision": 1, + "explanation": "Looser coupling gives a narrower, lower transfer curve; in the shown family, curve c is less coupled than curve a.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 7 + }, + "AD228": { + "revision": 1, + "explanation": "Critical coupling gives the flattest single peak at maximum useful width, while overcritical coupling creates the double-humped response; those are curves b and a respectively.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 7 + }, + "AD229": { + "revision": 1, + "explanation": "Critical coupling is the coupling just before the response splits into a double hump: the curve has maximum width while the resonance maximum is still flat.", + "source": "https://50ohm.de/A_schwingkreis_2.html", + "confidence": 8 + }, + "AD301": { + "revision": 1, + "explanation": "In each series string the cell voltages add, giving $30 x 0.6 V = 18 V$; four identical strings in parallel add their short-circuit currents to 4 A.", + "source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html", + "confidence": 7 + }, + "AD302": { + "revision": 1, + "explanation": "The unloaded smoothing capacitor charges close to the peak of the secondary AC voltage; about 15 V RMS times $sqrt(2)$ gives roughly 21 V.", + "source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html", + "confidence": 7 + }, + "AD303": { + "revision": 1, + "explanation": "A 20:1 transformer gives 230 V / 20 = 11.5 V RMS; the peak is about 16.3 V, and adding 50 percent safety gives about 24.4 V, so choose at least 25 V.", + "source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html", + "confidence": 7 + }, + "AD304": { + "revision": 1, + "explanation": "A 5:1 transformer gives 46 V RMS, or about 65 V peak; the diode must withstand about twice that peak plus 20 percent, giving about 156 V.", + "source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html", + "confidence": 7 + }, + "AD305": { + "revision": 1, + "explanation": "In a bridge rectifier, two diodes conduct on each half-cycle so current through the load always has the same polarity; the correct diagram has all four diodes oriented for that path.", + "source": "https://50ohm.de/NEA_brueckengleichrichter.html", + "confidence": 7 + }, + "AD306": { + "revision": 1, + "explanation": "The secondary peak is the mains peak divided by 8: $230 V x 1.414 / 8$ is about 40.6 V, which is the unloaded capacitor voltage.", + "source": "https://50ohm.de/NEA_brueckengleichrichter.html", + "confidence": 7 + }, + "AD307": { + "revision": 1, + "explanation": "A full-wave rectifier uses both half-cycles and routes them through the load with the indicated same output polarity.", + "source": "https://50ohm.de/NEA_vollweggleichrichter.html", + "confidence": 7 + }, + "AD308": { + "revision": 1, + "explanation": "The rectifier output is pulsating DC: the negative half-cycles are folded to the same polarity rather than appearing as negative voltage.", + "source": "https://50ohm.de/NEA_vollweggleichrichter.html", + "confidence": 7 + }, + "AD309": { + "revision": 1, + "explanation": "The ripple span is the difference between the high and low points, 3 V, and a full-wave rectifier on 50 Hz mains produces ripple at 100 Hz.", + "source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html", + "confidence": 7 + }, + "AD310": { + "revision": 1, + "explanation": "A full-wave rectifier produces one output pulse for each half-cycle, so 50 Hz mains becomes 100 Hz ripple frequency.", + "source": "https://50ohm.de/NEA_vollweggleichrichter.html", + "confidence": 8 + }, + "AD311": { + "revision": 1, + "explanation": "In a switch-mode supply the electronic switch controls energy transfer by changing pulse width, so block E acts as the pulse-width modulator.", + "source": "https://50ohm.de/A_schaltnetzteil_2.html", + "confidence": 7 + }, + "AD312": { + "revision": 1, + "explanation": "The fast switching action produces harmonics and broadband unwanted spectral components, which is the main EMC disadvantage of the shown switch-mode supply.", + "source": "https://50ohm.de/A_schaltnetzteil_2.html", + "confidence": 7 + }, + "AD313": { + "revision": 1, + "explanation": "Regularly spaced unwanted signals around 120 kHz are typical of switch-mode supply switching frequency and its related emissions.", + "source": "https://50ohm.de/A_schaltnetzteil_2.html", + "confidence": 8 + }, + "AD314": { + "revision": 1, + "explanation": "A mains input filter uses a common-mode choke and capacitors to keep switching interference from being conducted back into the power network.", + "source": "https://50ohm.de/A_schaltnetzteil_2.html", + "confidence": 7 + }, + "AD315": { + "revision": 1, + "explanation": "The Z-diode regulator clamps the output near the Zener voltage, so the output between A and B is approximately 5 V despite the varying input.", + "source": "https://50ohm.de/A_spannungsstabilisierung.html", + "confidence": 7 + }, + "AD316": { + "revision": 1, + "explanation": "A linear regulator needs headroom: its input voltage must be higher than the regulated output voltage so the pass element can control the drop.", + "source": "https://50ohm.de/A_spannungsstabilisierung.html", + "confidence": 7 + }, + "AD317": { + "revision": 1, + "explanation": "A fixed 12 V regulator absorbs the allowed input variation as internal voltage drop, so the output variation is nearly zero while it remains in regulation.", + "source": "https://50ohm.de/A_spannungsstabilisierung.html", + "confidence": 7 + }, + "AD318": { + "revision": 1, + "explanation": "The load current is $5 V / 10 ohm = 0.5 A$ and the regulator drops $13.8 V - 5 V = 8.8 V$; loss is $8.8 V x 0.5 A = 4.4 W$.", + "source": "https://50ohm.de/A_spannungsstabilisierung.html", + "confidence": 7 + }, + "AD319": { + "revision": 1, + "explanation": "A linear regulator dissipates the voltage drop times current: $(13.8 V - 9 V) x 0.9 A = 4.32 W$.", + "source": "https://50ohm.de/A_spannungsstabilisierung.html", + "confidence": 8 + }, + "AD320": { + "revision": 1, + "explanation": "Efficiency is output power over input power: $5 V x 0.450 A$ divided by $13.8 V x 0.455 A$ is about 0.36.", + "source": "https://50ohm.de/A_spannungsstabilisierung.html", + "confidence": 8 + }, + "AD321": { + "revision": 1, + "explanation": "The load power is $4.7 V x 10 mA = 47 mW$; input power is $13.8 V x (10 + 15) mA = 345 mW$, so efficiency is about 0.14.", + "source": "https://50ohm.de/A_spannungsstabilisierung.html", + "confidence": 7 + }, + "AD322": { + "revision": 1, + "explanation": "A Bias-T combines DC feed and RF signal on one cable while separating them again at the ports with an inductor and capacitor.", + "source": "https://50ohm.de/NEA_fernspeiseweiche.html", + "confidence": 8 + }, + "AD323": { + "revision": 1, + "explanation": "The circuit combines a DC feed path through an inductor with an RF path through a coupling capacitor, which is the structure of a Bias-T.", + "source": "https://50ohm.de/NEA_fernspeiseweiche.html", + "confidence": 7 + }, + "AD324": { + "revision": 1, + "explanation": "C1 is the RF coupling capacitor toward the receiver; it passes RF but blocks the DC supply from reaching the receiver input.", + "source": "https://50ohm.de/NEA_fernspeiseweiche.html", + "confidence": 7 + }, + "AD325": { + "revision": 1, + "explanation": "The Bias-T inductor is in the DC feed path, so it must safely carry the supply current for the remote device.", + "source": "https://50ohm.de/NEA_fernspeiseweiche.html", + "confidence": 7 + }, + "AD401": { + "revision": 1, + "explanation": "The collector is the AC-common terminal and the output is taken from the emitter, so this is the collector configuration, also called an emitter follower.", + "source": "https://50ohm.de/A_kollektorschaltung.html", + "confidence": 7 + }, + "AD402": { + "revision": 1, + "explanation": "An emitter follower has voltage gain just below unity because the emitter follows the base voltage, and it is non-inverting, so the phase shift is 0 degrees.", + "source": "https://50ohm.de/A_kollektorschaltung.html", + "confidence": 7 + }, + "AD403": { + "revision": 1, + "explanation": "A collector configuration buffers a high-impedance source into a low-impedance load; its current gain is useful even though voltage gain is below one.", + "source": "https://50ohm.de/A_kollektorschaltung.html", + "confidence": 7 + }, + "AD404": { + "revision": 1, + "explanation": "Because it has high input impedance and low output impedance, an emitter follower can isolate an oscillator from changing load impedance.", + "source": "https://50ohm.de/A_kollektorschaltung.html", + "confidence": 7 + }, + "AD405": { + "revision": 1, + "explanation": "In a collector configuration the emitter voltage rises and falls with the base signal, so input and output have the same phase.", + "source": "https://50ohm.de/A_kollektorschaltung.html", + "confidence": 8 + }, + "AD406": { + "revision": 1, + "explanation": "Without DC bias the transistor conducts only when the base-emitter voltage exceeds about 0.6 V; the collector voltage then dips, so the output is a clipped, inverted pulse-like waveform.", + "source": "https://50ohm.de/A_emitterschaltung.html", + "confidence": 7 + }, + "AD407": { + "revision": 1, + "explanation": "In an emitter configuration, increasing base current increases collector current and therefore the voltage drop across the collector resistor; the collector output voltage moves oppositely, giving 180 degrees phase shift.", + "source": "https://50ohm.de/A_emitterschaltung.html", + "confidence": 8 + }, + "AD408": { + "revision": 1, + "explanation": "The emitter-stage output is taken at the collector, so the collector waveform is inverted relative to the input while the bias and coupling points keep their shown DC roles.", + "source": "https://50ohm.de/A_emitterschaltung.html", + "confidence": 7 + }, + "AD409": { + "revision": 1, + "explanation": "The emitter is the common reference for input and output, with the output taken at the collector through a coupling capacitor, which identifies an emitter configuration.", + "source": "https://50ohm.de/A_emitterschaltung.html", + "confidence": 7 + }, + "AD410": { + "revision": 1, + "explanation": "A bypassed emitter stage can provide large voltage gain, and the collector output is inverted relative to the base input, so the phase shift is 180 degrees.", + "source": "https://50ohm.de/A_emitterschaltung.html", + "confidence": 7 + }, + "AD411": { + "revision": 1, + "explanation": "R1 and R2 form a voltage divider feeding the base, setting the transistor's DC bias point before the AC signal is applied.", + "source": "https://50ohm.de/A_emitterschaltung.html", + "confidence": 7 + }, + "AD412": { + "revision": 1, + "explanation": "The coupling capacitors pass the AC signal into and out of the stage while blocking the DC bias voltages from adjacent circuits.", + "source": "https://50ohm.de/A_emitterschaltung.html", + "confidence": 7 + }, + "AD413": { + "revision": 1, + "explanation": "The emitter bypass capacitor shorts the emitter resistor for AC, reducing emitter degeneration and therefore maximizing AC voltage gain.", + "source": "https://50ohm.de/A_emitterschaltung.html", + "confidence": 7 + }, + "AD414": { + "revision": 1, + "explanation": "Removing the emitter bypass capacitor leaves the emitter resistor active for AC feedback, so emitter degeneration lowers the voltage gain.", + "source": "https://50ohm.de/A_emitterschaltung.html", + "confidence": 7 + }, + "AD415": { + "revision": 1, + "explanation": "With no emitter bypass capacitor, the emitter resistor provides negative feedback and the stage gain drops from a large value to roughly the resistor-ratio value, about 10 here.", + "source": "https://50ohm.de/A_emitterschaltung.html", + "confidence": 7 + }, + "AD416": { + "revision": 1, + "explanation": "Moving the bias point upward increases the conduction angle: C is below cutoff most of the cycle, B sits at cutoff, AB is slightly above it, and A conducts for the whole cycle.", + "source": "https://50ohm.de/A_verstaerker_klasse.html", + "confidence": 7 + }, + "AD417": { + "revision": 1, + "explanation": "A bipolar transistor's collector current is controlled by base-emitter voltage, so raising that voltage in B operation drives the transistor harder and greatly increases collector current.", + "source": "https://50ohm.de/A_verstaerker_klasse.html", + "confidence": 8 + }, + "AD418": { + "revision": 1, + "explanation": "Class C is biased below cutoff; with no drive the transistor does not conduct, so the quiescent current is approximately zero.", + "source": "https://50ohm.de/A_verstaerker_klasse.html", + "confidence": 8 + }, + "AD419": { + "revision": 1, + "explanation": "Class A keeps the device conducting over the full signal cycle, giving good linearity and low harmonics at the cost of high quiescent current and poor efficiency around 40%.", + "source": "https://50ohm.de/A_verstaerker_klasse.html", + "confidence": 8 + }, + "AD420": { + "revision": 1, + "explanation": "Class B biases near cutoff so quiescent current is very small; with push-pull operation it can be fairly linear and efficient, up to about 80%.", + "source": "https://50ohm.de/A_verstaerker_klasse.html", + "confidence": 8 + }, + "AD421": { + "revision": 1, + "explanation": "Class C conducts for less than half the cycle, so it is very efficient but strongly nonlinear, producing many harmonics and no quiescent current.", + "source": "https://50ohm.de/A_verstaerker_klasse.html", + "confidence": 8 + }, + "AD422": { + "revision": 1, + "explanation": "SSB needs linear amplification because information is carried in amplitude and phase; class C is nonlinear, while A, AB, and B can be used for linear RF power stages.", + "source": "https://50ohm.de/A_verstaerker_klasse.html", + "confidence": 8 + }, + "AD423": { + "revision": 1, + "explanation": "Overdrive pushes a nominally linear AB amplifier into nonlinear operation; distorted SSB creates unwanted side products that appear as splatter on adjacent frequencies.", + "source": "https://50ohm.de/A_verstaerker_klasse.html", + "confidence": 8 + }, + "AD424": { + "revision": 1, + "explanation": "The DC input power is $50 V x 2 A = 100 W$; class A efficiency is about 40%, so expected RF output is about $0.4 x 100 W = 40 W$.", + "source": "https://50ohm.de/A_verstaerker_wirkungsgrad.html", + "confidence": 8 + }, + "AD425": { + "revision": 1, + "explanation": "The DC input power is $50 V x 2 A = 100 W$; using about 85% efficiency for class C gives about $0.85 x 100 W = 85 W$ RF output.", + "source": "https://50ohm.de/A_verstaerker_wirkungsgrad.html", + "confidence": 8 + }, + "AD426": { + "revision": 1, + "explanation": "A 16 dB power gain is a ratio of $10^(16/10) = 39.8$, so 1 W input becomes about 40 W output.", + "source": "https://50ohm.de/A_verstaerkungsleistung.html", + "confidence": 8 + }, + "AD427": { + "revision": 1, + "explanation": "For equal impedances, voltage gain in dB is $20 log10(U2/U1)$; $20 log10(4 mV / 1 mV) = 20 log10(4) = 12 dB$.", + "source": "https://50ohm.de/A_verstaerkungsleistung.html", + "confidence": 8 + }, + "AD428": { + "revision": 1, + "explanation": "Power gain in dB is $10 log10(P2/P1)$; $10 log10(38 W / 2.5 W) = 10 log10(15.2) = 11.8 dB$.", + "source": "https://50ohm.de/A_verstaerkungsleistung.html", + "confidence": 8 + }, + "AD429": { + "revision": 1, + "explanation": "Efficiency is useful RF output divided by DC input: $10 W / 25 W = 0.40$, or 40%.", + "source": "https://50ohm.de/A_verstaerker_wirkungsgrad.html", + "confidence": 8 + }, + "AD430": { + "revision": 1, + "explanation": "The DC input power is $12.5 V x 16 A = 200 W$; efficiency is $90 W / 200 W = 0.45$, or 45%.", + "source": "https://50ohm.de/A_verstaerker_wirkungsgrad.html", + "confidence": 8 + }, + "AD431": { + "revision": 1, + "explanation": "Linear amplification scales the input waveform without changing its shape, so the output curve follows the same waveform at a larger amplitude.", + "source": "https://50ohm.de/A_verstaerker_linearverstaerker.html", + "confidence": 8 + }, + "AD432": { + "revision": 1, + "explanation": "Self-oscillation happens when output energy is coupled back to the input with enough gain and phase to act as feedback, turning the amplifier into an unintended oscillator.", + "source": "https://50ohm.de/A_verstaerker_eigenschwingung.html", + "confidence": 8 + }, + "AD433": { + "revision": 1, + "explanation": "A microphone amplifier should pass the speech band while attenuating both too-low and too-high audio frequencies, which is exactly a band-pass response.", + "source": "https://50ohm.de/A_slide_a_grundlegende_schaltungen.html", + "confidence": 7 + }, + "AD501": { + "revision": 1, + "explanation": "A diode followed by an RC load recovers the envelope of an AM signal, so the circuit is an envelope demodulator for AM.", + "source": "https://50ohm.de/EA_demodulator.html", + "confidence": 7 + }, + "AD502": { + "revision": 1, + "explanation": "At point X the diode has rectified the AM IF waveform but the RC network has not yet fully smoothed it, so the signal follows the positive envelope with RF ripple remaining.", + "source": "https://50ohm.de/EA_demodulator.html", + "confidence": 7 + }, + "AD503": { + "revision": 1, + "explanation": "In an envelope detector the extra output from the rectified envelope can be filtered into a DC control voltage, which is used as an AGC/regulating voltage.", + "source": "https://50ohm.de/EA_demodulator.html", + "confidence": 7 + }, + "AD504": { + "revision": 1, + "explanation": "A tuned circuit offset from the IF converts FM frequency deviations into amplitude changes, which a diode detector can then recover as audio; that is a slope discriminator.", + "source": "https://50ohm.de/EA_demodulator.html", + "confidence": 7 + }, + "AD505": { + "revision": 1, + "explanation": "A PLL can follow the frequency of an FM signal; the VCO control voltage is then proportional to the original modulation, so the block is a PLL FM demodulator.", + "source": "https://50ohm.de/EA_demodulator.html", + "confidence": 7 + }, + "AD506": { + "revision": 1, + "explanation": "A product detector mixes the SSB signal with a locally regenerated carrier/BFO so the sideband is converted back to audio.", + "source": "https://50ohm.de/EA_demodulator.html", + "confidence": 7 + }, + "AD507": { + "revision": 1, + "explanation": "The circuit varies the RF carrier amplitude in step with the audio signal, which is the defining operation of an AM modulator.", + "source": "https://50ohm.de/A_modulatoren.html", + "confidence": 7 + }, + "AD508": { + "revision": 1, + "explanation": "The audio voltage drives a varicap in the oscillator tank circuit; changing capacitance changes oscillator frequency, so the generated signal is FM.", + "source": "https://50ohm.de/A_modulatoren.html", + "confidence": 7 + }, + "AD509": { + "revision": 1, + "explanation": "For FM the audio amplitude determines frequency deviation; antiparallel diodes and the level control limit and set that deviation, i.e. the FM deviation or hub.", + "source": "https://50ohm.de/A_modulatoren.html", + "confidence": 7 + }, + "AD510": { + "revision": 1, + "explanation": "A balanced mixer cancels the carrier when adjusted symmetrically; the sum and difference products remain as the two AM sidebands.", + "source": "https://50ohm.de/A_modulatoren.html", + "confidence": 8 + }, + "AD601": { + "revision": 1, + "explanation": "A VCO is voltage controlled: a control voltage changes a tuning element such as a varicap, and the oscillator frequency follows that voltage.", + "source": "https://50ohm.de/A_oszillator_vco.html", + "confidence": 8 + }, + "AD602": { + "revision": 1, + "explanation": "TCXO means Temperature Compensated Crystal Oscillator: a crystal oscillator whose circuit compensates temperature effects instead of holding the whole oscillator in an oven.", + "source": "https://50ohm.de/A_oszillator_tcxo_ocxo.html", + "confidence": 8 + }, + "AD603": { + "revision": 1, + "explanation": "The abbreviation TCXO expands to Temperature Compensated Crystal Oscillator, i.e. a temperature-compensated crystal oscillator.", + "source": "https://50ohm.de/A_oszillator_tcxo_ocxo.html", + "confidence": 8 + }, + "AD604": { + "revision": 1, + "explanation": "At 3 cm, small reference errors are multiplied into large RF errors; SSB/SDR operation therefore needs a stable reference, and TCXO is the stable choice among the listed options.", + "source": "https://50ohm.de/A_oszillator_tcxo_ocxo.html", + "confidence": 8 + }, + "AD605": { + "revision": 1, + "explanation": "An OCXO keeps the crystal oscillator at a controlled oven temperature, so it is more stable than a plain XO, a TCXO, or a VCO.", + "source": "https://50ohm.de/A_oszillator_tcxo_ocxo.html", + "confidence": 8 + }, + "AD606": { + "revision": 1, + "explanation": "A GPSDO combines a stable local oscillator for short-term stability with a GPS-derived external reference for long-term correction.", + "source": "https://50ohm.de/A_oszillator_gpsdo.html", + "confidence": 8 + }, + "AD607": { + "revision": 1, + "explanation": "A VFO's frequency depends partly on its operating voltage; stabilized DC prevents supply changes from pulling the oscillator frequency.", + "source": "https://50ohm.de/A_oszillator_spannungsstabilitaet.html", + "confidence": 8 + }, + "AD608": { + "revision": 1, + "explanation": "The VFO needs voltage-stabilized DC because oscillator frequency can shift when the supply voltage changes.", + "source": "https://50ohm.de/A_oszillator_spannungsstabilitaet.html", + "confidence": 8 + }, + "AD609": { + "revision": 1, + "explanation": "CW keying can momentarily change oscillator supply voltage; if the oscillator frequency jumps with those voltage changes, the note sounds like chirp.", + "source": "https://50ohm.de/A_oszillator_spannungsstabilitaet.html", + "confidence": 8 + }, + "AD610": { + "revision": 1, + "explanation": "A buffer stage isolates the oscillator from following stages, so load changes cannot easily pull the oscillator frequency.", + "source": "https://50ohm.de/EA_oszillator_schaltungen.html", + "confidence": 8 + }, + "AD611": { + "revision": 1, + "explanation": "Unwanted RF feedback into a VFO changes the conditions in the oscillator circuit, which can pull or modulate the generated frequency.", + "source": "https://50ohm.de/A_oszillator_vco.html", + "confidence": 8 + }, + "AD612": { + "revision": 1, + "explanation": "PA current and RF can disturb a shared supply; filtering and decoupling the VFO supply keeps those disturbances from pulling the oscillator.", + "source": "https://50ohm.de/A_oszillator_spannungsstabilitaet.html", + "confidence": 8 + }, + "AD613": { + "revision": 1, + "explanation": "Sustained oscillation needs positive feedback at the oscillation frequency: the returned signal must be in phase and at least as large as the signal it reinforces.", + "source": "https://50ohm.de/EA_oszillator_schaltungen.html", + "confidence": 8 + }, + "AD614": { + "revision": 1, + "explanation": "The LC resonator and capacitive divider form a Colpitts-style three-point oscillator, with the capacitive divider providing the feedback path.", + "source": "https://50ohm.de/EA_oszillator_schaltungen.html", + "confidence": 7 + }, + "AD615": { + "revision": 1, + "explanation": "The output should be taken at the low-impedance buffered point so the load disturbs the resonant circuit as little as possible; in the drawing that is point D.", + "source": "https://50ohm.de/EA_oszillator_schaltungen.html", + "confidence": 7 + }, + "AD616": { + "revision": 1, + "explanation": "C1 and C2 form the capacitive voltage divider of the Colpitts oscillator; a fraction of the output is fed back to sustain oscillation.", + "source": "https://50ohm.de/EA_oszillator_schaltungen.html", + "confidence": 7 + }, + "AD617": { + "revision": 1, + "explanation": "The transistor is used in collector configuration and the crystal sets the oscillation frequency; this circuit is a capacitively fed crystal oscillator on the crystal's fundamental frequency.", + "source": "https://50ohm.de/EA_oszillator_schaltungen.html", + "confidence": 7 + }, + "AD618": { + "revision": 1, + "explanation": "Point 3 is part of the frequency-determining resonant network; probe capacitance loads that point and therefore shifts the oscillator frequency.", + "source": "https://50ohm.de/EA_oszillator_schaltungen.html", + "confidence": 7 + }, + "AD619": { + "revision": 1, + "explanation": "The oscillator should be measured at the buffered output point, because probing the resonant circuit directly would add capacitance and detune it; in the drawing that is point 4.", + "source": "https://50ohm.de/EA_oszillator_schaltungen.html", + "confidence": 7 + }, + "AD620": { + "revision": 1, + "explanation": "The block diagram uses a clock, digital address/phase generation, a sine lookup table, and a D/A converter to synthesize the output, which is direct digital synthesis.", + "source": "https://50ohm.de/A_oszillator_dds.html", + "confidence": 7 + }, + "AD701": { + "revision": 1, + "explanation": "A basic PLL compares phase, filters the phase-detector output into a control voltage, and uses that voltage to steer a VCO.", + "source": "https://50ohm.de/A_oszillator_pll.html", + "confidence": 8 + }, + "AD702": { + "revision": 1, + "explanation": "In lock, the phase detector sees equal reference and divided-VCO frequencies, so the signals at the two detector inputs A and B have the same frequency.", + "source": "https://50ohm.de/A_oszillator_pll.html", + "confidence": 7 + }, + "AD703": { + "revision": 1, + "explanation": "In this integer-N PLL, the smallest output step equals the reference frequency at the phase detector, so a 12.5 kHz channel spacing requires 12.5 kHz at point A.", + "source": "https://50ohm.de/A_oszillator_pll.html", + "confidence": 7 + }, + "AD704": { + "revision": 1, + "explanation": "The divider ratio is output frequency divided by the 12.5 kHz reference: 12.000 MHz / 12.5 kHz = 960 and 14.000 MHz / 12.5 kHz = 1120.", + "source": "https://50ohm.de/A_oszillator_pll.html", + "confidence": 7 + }, + "AD705": { + "revision": 1, + "explanation": "A synthesizer locks its output to the reference oscillator, so long-term accuracy and stability mainly follow the quartz reference, not the VCO or dividers.", + "source": "https://50ohm.de/A_oszillator_pll.html", + "confidence": 8 + }, + "AD801": { + "revision": 1, + "explanation": "The drawing is a resistive pad: only resistors are arranged between input and output to reduce signal level while maintaining impedance.", + "source": "https://50ohm.de/A_daempfungsglieder.html", + "confidence": 7 + }, + "AD802": { + "revision": 1, + "explanation": "The circuit is a resistive attenuator, not a frequency-selective filter, because its resistor network dissipates part of the RF power as heat.", + "source": "https://50ohm.de/A_daempfungsglieder.html", + "confidence": 7 + }, + "AD803": { + "revision": 1, + "explanation": "For power ratios, 20 dB corresponds to $10^(20/10) = 100$, so input power is 100 times the load power.", + "source": "https://50ohm.de/A_daempfungsglieder.html", + "confidence": 7 + }, + "AD804": { + "revision": 1, + "explanation": "For power ratios, 6 dB corresponds approximately to $10^(6/10) = 3.98$, so the practical ratio is 4.", + "source": "https://50ohm.de/A_daempfungsglieder.html", + "confidence": 7 + }, + "AD805": { + "revision": 1, + "explanation": "A symmetrical attenuator designed for a 50 ohm system presents 50 ohm at its input when its output is terminated with the matching 50 ohm load.", + "source": "https://50ohm.de/A_daempfungsglieder.html", + "confidence": 7 + }, + "AD806": { + "revision": 1, + "explanation": "A 20 dB attenuator reduces power by a factor of 100, so 100 W input leaves 1 W at the matched load; the remaining 99 W is dissipated as heat in the pad.", + "source": "https://50ohm.de/A_daempfungsglieder.html", + "confidence": 7 + }, + "AE101": { + "revision": 2, + "explanation": "AFuV defines occupied bandwidth so that the mean power below the lower limit and above the upper limit is 0.5% each of the total mean transmitted power.", + "source": "https://www.gesetze-im-internet.de/afuv_2005/__2.html", + "confidence": 10 + }, + "AE201": { + "revision": 1, + "explanation": "At 100% AM modulation the envelope just reaches zero at its minimum but does not cross or flatten; that is the largest undistorted AM modulation depth.", + "source": "https://50ohm.de/A_am_2.html", + "confidence": 7 + }, + "AE202": { + "revision": 1, + "explanation": "AM modulation depth is the modulation-envelope amplitude divided by the carrier amplitude; the oscilloscope shows about 3 V modulation on a 6 V carrier, giving 0.5 or 50%.", + "source": "https://50ohm.de/A_am_2.html", + "confidence": 7 + }, + "AE203": { + "revision": 1, + "explanation": "Overmodulation is AM with modulation depth above 100%; the envelope is driven through zero or pinched off, which causes distortion and sideband splatter.", + "source": "https://50ohm.de/A_am_2.html", + "confidence": 7 + }, + "AE204": { + "revision": 1, + "explanation": "AM above 100% modulation overdrives the envelope and creates distortion products, so the modulation depth must stay below 100% to avoid splatter.", + "source": "https://50ohm.de/A_am_2.html", + "confidence": 8 + }, + "AE205": { + "revision": 1, + "explanation": "Overmodulating SSB makes the signal path nonlinear; the resulting distortion spreads energy outside the intended sideband as splatter.", + "source": "https://50ohm.de/A_ssb_3.html", + "confidence": 8 + }, + "AE206": { + "revision": 1, + "explanation": "A balanced mixer can cancel the carrier while leaving the two sidebands, producing a double-sideband suppressed-carrier signal for SSB generation.", + "source": "https://50ohm.de/A_modulatoren.html", + "confidence": 8 + }, + "AE207": { + "revision": 1, + "explanation": "A two-tone SSB test produces a characteristic varying RF envelope used to judge linearity and PEP; it is not a constant-envelope FM or simple CW trace.", + "source": "https://50ohm.de/A_ssb_3.html", + "confidence": 7 + }, + "AE208": { + "revision": 1, + "explanation": "The RF bandwidth of an SSB phone signal is approximately the bandwidth of the applied audio, so limiting speech audio to about 2.7 kHz keeps the SSB signal narrow.", + "source": "https://50ohm.de/A_ssb_3.html", + "confidence": 8 + }, + "AE209": { + "revision": 1, + "explanation": "SSB phone is normally limited to about 2.7 kHz, so about 3 kHz spacing gives a small guard margin between adjacent SSB signals.", + "source": "https://50ohm.de/A_ssb_3.html", + "confidence": 8 + }, + "AE210": { + "revision": 1, + "explanation": "An audio dynamic compressor reduces the difference between loud and quiet speech parts, so the modulation has a smaller dynamic range.", + "source": "https://50ohm.de/A_ssb_3.html", + "confidence": 8 + }, + "AE211": { + "revision": 1, + "explanation": "By lifting quieter speech components and reducing dynamic range, compression raises the average SSB output power without requiring higher peaks when set correctly.", + "source": "https://50ohm.de/A_ssb_3.html", + "confidence": 8 + }, + "AE212": { + "revision": 1, + "explanation": "Too much compression overprocesses the speech and can drive distortion/splatter, so the received audio becomes less intelligible rather than clearer.", + "source": "https://50ohm.de/A_ssb_3.html", + "confidence": 8 + }, + "AE213": { + "revision": 1, + "explanation": "An equalizer shapes the microphone audio spectrum, letting the transmitter emphasize or reduce frequency ranges to suit the operator's voice.", + "source": "https://50ohm.de/A_ssb_3.html", + "confidence": 8 + }, + "AE214": { + "revision": 1, + "explanation": "Amplitude changes that are slower and less abrupt occupy less spectrum; the shown signal with the gentlest amplitude variation therefore has the smallest bandwidth.", + "source": "https://50ohm.de/NEA_symbolumschaltung_bandbreite.html", + "confidence": 7 + }, + "AE301": { + "revision": 1, + "explanation": "In FM, the modulating signal frequency sets how often the RF carrier frequency is moved back and forth; the modulation amplitude sets how far it moves.", + "source": "https://50ohm.de/A_fm_3.html", + "confidence": 8 + }, + "AE302": { + "revision": 1, + "explanation": "Impulse noise mainly changes amplitude; FM carries the information in frequency deviation, so amplitude disturbances have less effect than with AM or SSB.", + "source": "https://50ohm.de/A_fm_3.html", + "confidence": 8 + }, + "AE303": { + "revision": 1, + "explanation": "A varicap changes capacitance with the applied audio/control voltage; in an oscillator tank this shifts the oscillator frequency, producing FM.", + "source": "https://50ohm.de/A_fm_3.html", + "confidence": 8 + }, + "AE304": { + "revision": 1, + "explanation": "Carson's rule shows FM bandwidth increases with both deviation and the highest modulation frequency, so too high an audio frequency makes the RF bandwidth too large.", + "source": "https://50ohm.de/A_fm_3.html", + "confidence": 8 + }, + "AE305": { + "revision": 1, + "explanation": "For FM speech, larger deviation represents a larger audio amplitude after demodulation, so the received audio becomes louder.", + "source": "https://50ohm.de/A_fm_3.html", + "confidence": 8 + }, + "AE306": { + "revision": 1, + "explanation": "Excessive FM deviation widens the transmitted spectrum, so the signal can spill into adjacent channels and cause interference.", + "source": "https://50ohm.de/A_fm_3.html", + "confidence": 8 + }, + "AE307": { + "revision": 1, + "explanation": "Stronger FM modulator drive increases deviation; higher deviation increases the occupied RF bandwidth.", + "source": "https://50ohm.de/A_fm_3.html", + "confidence": 8 + }, + "AE308": { + "revision": 1, + "explanation": "Carson's rule gives $B = 2 x (deviation + highest modulation frequency)$, so $2 x (2.5 kHz + 2.7 kHz) = 10.4 kHz$.", + "source": "https://50ohm.de/A_fm_3.html", + "confidence": 8 + }, + "AE309": { + "revision": 1, + "explanation": "Using Carson's rule, $B = 2 x (1.8 kHz + 2.0 kHz) = 7.6 kHz$; the 145 MHz carrier frequency does not enter this bandwidth estimate.", + "source": "https://50ohm.de/A_fm_3.html", + "confidence": 8 + }, + "AE310": { + "revision": 1, + "explanation": "Narrowband FM in a 12.5 kHz channel uses a typical peak deviation of about 2.5 kHz, leaving room for modulation sidebands and channel spacing.", + "source": "https://50ohm.de/A_fm_3.html", + "confidence": 8 + }, + "AE311": { + "revision": 1, + "explanation": "Rearrange Carson's rule: $f_mod = B/2 - deviation = 10 kHz/2 - 2.5 kHz = 2.5 kHz$.", + "source": "https://50ohm.de/A_fm_3.html", + "confidence": 8 + }, + "AE312": { + "revision": 1, + "explanation": "Rearrange Carson's rule: deviation $= B/2 - f_mod = 10 kHz/2 - 2.7 kHz = 2.3 kHz$.", + "source": "https://50ohm.de/A_fm_3.html", + "confidence": 8 + }, + "AE313": { + "revision": 1, + "explanation": "PM means phase modulation: the information signal changes the phase of the carrier rather than its amplitude or polarization.", + "source": "https://50ohm.de/EA_pm.html", + "confidence": 8 + }, + "AE401": { + "revision": 1, + "explanation": "PSK keeps the carrier amplitude essentially constant but introduces abrupt phase changes; the correct trace is the one where the sine wave jumps phase rather than changing amplitude or frequency smoothly.", + "source": "https://50ohm.de/NEA_psk.html", + "confidence": 7 + }, + "AE402": { + "revision": 1, + "explanation": "BPSK has two phase states, so each symbol carries one bit; QPSK has four phase states, so each symbol carries two bits.", + "source": "https://50ohm.de/A_mehrwertige_verfahren.html", + "confidence": 8 + }, + "AE403": { + "revision": 1, + "explanation": "QAM maps data onto combinations of carrier amplitude and carrier phase, giving more possible symbols than amplitude-only modulation.", + "source": "https://50ohm.de/A_qam.html", + "confidence": 8 + }, + "AE404": { + "revision": 1, + "explanation": "QAM is commonly generated by amplitude-modulating two carriers that are 90 degrees apart, then adding them as I and Q components.", + "source": "https://50ohm.de/EA_iq_verfahren.html", + "confidence": 8 + }, + "AE405": { + "revision": 1, + "explanation": "With two symbol frequencies, each symbol represents one bit, so 45.45 baud corresponds directly to 45.45 bit/s.", + "source": "https://50ohm.de/A_mehrwertige_verfahren.html", + "confidence": 8 + }, + "AE406": { + "revision": 1, + "explanation": "Four symbol frequencies encode two bits per symbol; data rate is symbol rate times bits per symbol, so $23.4 x 2 = 46.8 bit/s$.", + "source": "https://50ohm.de/A_mehrwertige_verfahren.html", + "confidence": 8 + }, + "AE407": { + "revision": 1, + "explanation": "Synchronization means sender and receiver agree on timing, so the receiver knows where symbols or frames begin and can decode them correctly.", + "source": "https://50ohm.de/NEA_synchronisation.html", + "confidence": 8 + }, + "AE408": { + "revision": 1, + "explanation": "Source coding reduces the original message data, for example by removing redundancy or irrelevant information through compression.", + "source": "https://50ohm.de/NEA_quellencodierung.html", + "confidence": 8 + }, + "AE409": { + "revision": 1, + "explanation": "Channel coding deliberately adds redundancy before transmission so the receiver can detect or correct errors caused by the channel.", + "source": "https://50ohm.de/NEA_kanalcodierung.html", + "confidence": 8 + }, + "AE410": { + "revision": 1, + "explanation": "CRC is a checksum-like error detection method for data blocks; it computes redundant check information from the block contents.", + "source": "https://50ohm.de/NEA_fehlererkennung.html", + "confidence": 8 + }, + "AE411": { + "revision": 1, + "explanation": "A single parity bit flips its check result when an odd number of bits is wrong; even numbers of bit errors preserve the parity and can pass undetected.", + "source": "https://50ohm.de/NEA_fehlererkennung.html", + "confidence": 8 + }, + "AE412": { + "revision": 1, + "explanation": "A passing parity check only proves the parity is unchanged; that can mean no error or an even number of bit errors including the parity bit.", + "source": "https://50ohm.de/NEA_fehlererkennung.html", + "confidence": 8 + }, + "AE413": { + "revision": 1, + "explanation": "Without FEC the receiver cannot reconstruct corrupted packet contents from redundancy, so correction requires requesting or receiving the packet again.", + "source": "https://50ohm.de/EA_fehlerkorrektur.html", + "confidence": 8 + }, + "AE414": { + "revision": 1, + "explanation": "Forward error correction needs redundant information in the transmitted data, so the receiver has enough extra checks to locate and correct errors.", + "source": "https://50ohm.de/EA_fehlerkorrektur.html", + "confidence": 8 + }, + "AE415": { + "revision": 1, + "explanation": "Faster symbol changes mean faster amplitude, frequency, or phase transitions, and faster transitions require a wider spectrum.", + "source": "https://50ohm.de/NEA_symbolumschaltung_bandbreite.html", + "confidence": 8 + }, + "AE416": { + "revision": 1, + "explanation": "Shannon-Hartley gives the theoretical maximum error-free data rate for a channel from its bandwidth and signal-to-noise ratio.", + "source": "https://50ohm.de/A_shannon_hartley_gesetzt.html", + "confidence": 8 + }, + "AE417": { + "revision": 1, + "explanation": "At 0 dB SNR the linear SNR is 1, so $C = B x log2(1 + 1) = B$; 2.7 kHz therefore gives about 2.7 kbit/s.", + "source": "https://50ohm.de/A_shannon_hartley_gesetzt.html", + "confidence": 8 + }, + "AE418": { + "revision": 1, + "explanation": "At 0 dB SNR, Shannon-Hartley reduces to capacity approximately equal to bandwidth in bit/s, so 10 MHz gives about 10 Mbit/s.", + "source": "https://50ohm.de/A_shannon_hartley_gesetzt.html", + "confidence": 8 + }, + "AE419": { + "revision": 1, + "explanation": "30 dB SNR is a linear ratio of 1000, so capacity is $10 MHz x log2(1001)$, about $10 MHz x 10 = 100 Mbit/s$.", + "source": "https://50ohm.de/A_shannon_hartley_gesetzt.html", + "confidence": 8 + }, + "AE420": { + "revision": 1, + "explanation": "-20 dB SNR is a linear ratio of 0.01; $2700 x log2(1.01)$ is about 39 bit/s, so transmission is possible but very slow.", + "source": "https://50ohm.de/A_shannon_hartley_gesetzt.html", + "confidence": 8 + }, + "AE421": { + "revision": 1, + "explanation": "OFDM spreads data across many narrow subcarriers; a narrowband interferer damages only some carriers, and redundancy can recover the lost information.", + "source": "https://50ohm.de/EA_ofdm.html", + "confidence": 8 + }, + "AE422": { + "revision": 1, + "explanation": "OFDM uses longer symbols on many subcarriers, so delayed copies from multipath overlap less destructively and can be handled better with redundant coding.", + "source": "https://50ohm.de/EA_ofdm.html", + "confidence": 8 + }, + "AF101": { + "revision": 1, + "explanation": "Increasing power from 25 W to 100 W is a factor of 4, or +6 dB; one S-unit corresponds to 6 dB.", + "source": "https://50ohm.de/NEA_s_meter.html", + "confidence": 8 + }, + "AF102": { + "revision": 1, + "explanation": "Increasing power from 100 W to 400 W is again a factor of 4, which is +6 dB, equal to one S-unit.", + "source": "https://50ohm.de/NEA_s_meter.html", + "confidence": 8 + }, + "AF103": { + "revision": 1, + "explanation": "A tenfold power increase is +10 dB. From S8, +6 dB reaches S9 and the remaining +4 dB gives S9+4 dB.", + "source": "https://50ohm.de/NEA_s_meter.html", + "confidence": 8 + }, + "AF104": { + "revision": 1, + "explanation": "S7 to S9 is two S-units, or 12 dB; S9+8 dB makes the total increase 20 dB, which is a 100-fold power ratio.", + "source": "https://50ohm.de/NEA_s_meter.html", + "confidence": 8 + }, + "AF105": { + "revision": 1, + "explanation": "One S-unit lower is -6 dB in voltage, i.e. half the input voltage; half of 50 microvolt is 25 microvolt.", + "source": "https://50ohm.de/NEA_s_meter.html", + "confidence": 8 + }, + "AF106": { + "revision": 1, + "explanation": "In a simple superhet, the wanted signal and its image are on opposite sides of the local oscillator by one IF each, so their separation is twice the IF.", + "source": "https://50ohm.de/EA_spiegelfrequenzen.html", + "confidence": 8 + }, + "AF107": { + "revision": 1, + "explanation": "The IF is $24.94 MHz - 14.24 MHz = 10.70 MHz$; the image on the other side of the oscillator is $24.94 MHz + 10.70 MHz = 35.64 MHz$.", + "source": "https://50ohm.de/EA_spiegelfrequenzen.html", + "confidence": 7 + }, + "AF108": { + "revision": 1, + "explanation": "With high-side injection the oscillator is $28.5 MHz + 10.7 MHz = 39.2 MHz$; the image is another IF above that, $39.2 MHz + 10.7 MHz = 49.9 MHz$.", + "source": "https://50ohm.de/EA_spiegelfrequenzen.html", + "confidence": 7 + }, + "AF109": { + "revision": 1, + "explanation": "A very high first IF moves the image by twice that IF, placing the image far away from the wanted HF band where RF filtering can reject it more easily.", + "source": "https://50ohm.de/A_ueberlagerungsempfaenger_einfachsuper_2.html", + "confidence": 8 + }, + "AF110": { + "revision": 1, + "explanation": "Image frequency separation is twice the IF, so the IF value mainly determines how far the image is from the wanted frequency and how easily it can be filtered.", + "source": "https://50ohm.de/EA_spiegelfrequenzen.html", + "confidence": 8 + }, + "AF111": { + "revision": 1, + "explanation": "A high first IF gives a large spacing between wanted and image frequencies, improving image-frequency rejection before the mixer.", + "source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html", + "confidence": 8 + }, + "AF112": { + "revision": 1, + "explanation": "In a double superhet, the high first IF is chosen mainly for image rejection, while later lower IF stages can provide selectivity.", + "source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html", + "confidence": 8 + }, + "AF113": { + "revision": 1, + "explanation": "A low second IF allows narrow, high-selectivity filters, so it is useful for good adjacent-signal separation.", + "source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html", + "confidence": 8 + }, + "AF114": { + "revision": 1, + "explanation": "The high first IF helps image rejection; after roofing-filter preselection, conversion to a lower second IF makes narrow filtering and selectivity easier.", + "source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html", + "confidence": 8 + }, + "AF115": { + "revision": 1, + "explanation": "Near selectivity is the ability to separate nearby signals, and that is set by the receiver's IF filters rather than by RF gain stages.", + "source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html", + "confidence": 8 + }, + "AF116": { + "revision": 1, + "explanation": "The first IF filter must not cut off any intended mode, so its bandwidth must be at least as wide as the widest receive mode the receiver is meant to handle.", + "source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html", + "confidence": 8 + }, + "AF117": { + "revision": 1, + "explanation": "The first mixer is driven by the tunable VFO, the second conversion by a fixed crystal oscillator, and the final product detector needs the BFO to recover SSB/CW audio.", + "source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html", + "confidence": 7 + }, + "AF118": { + "revision": 1, + "explanation": "High-side first conversion needs $21.1 MHz + 9 MHz = 30.1 MHz$ for the VFO; low-side conversion from 9 MHz to 460 kHz needs $9 MHz - 0.460 MHz = 8.54 MHz$ for the CO.", + "source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html", + "confidence": 7 + }, + "AF119": { + "revision": 1, + "explanation": "With both oscillators above their input signals, the VFO is $28.00 MHz + 10.70 MHz = 38.70 MHz$ and the second oscillator is $10.70 MHz + 0.460 MHz = 11.16 MHz$.", + "source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html", + "confidence": 7 + }, + "AF120": { + "revision": 1, + "explanation": "The chain can mix $3.65 MHz + 46.35 MHz$ to a 50 MHz first IF, then $50 MHz - 41 MHz$ to 9 MHz, then $9.455 MHz - 9 MHz$ to 455 kHz.", + "source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html", + "confidence": 7 + }, + "AF201": { + "revision": 1, + "explanation": "The wanted signal and image produce the same IF on opposite sides of the local oscillator, so their frequency spacing is twice the IF.", + "source": "https://50ohm.de/A_spiegelfrequenzen.html", + "confidence": 7 + }, + "AF202": { + "revision": 1, + "explanation": "The IF is $145.6 MHz - 134.9 MHz = 10.7 MHz$; the image is the other signal 10.7 MHz from the oscillator, $134.9 MHz - 10.7 MHz = 124.2 MHz$.", + "source": "https://50ohm.de/A_spiegelfrequenzen.html", + "confidence": 7 + }, + "AF203": { + "revision": 1, + "explanation": "The image is mirrored around the oscillator frequency: $2 x 39 MHz - 28.3 MHz = 49.7 MHz$.", + "source": "https://50ohm.de/A_spiegelfrequenzen.html", + "confidence": 8 + }, + "AF204": { + "revision": 1, + "explanation": "Image rejection must happen before the mixer, because the wanted signal and image become the same IF after mixing; therefore RF preselection determines image attenuation.", + "source": "https://50ohm.de/A_spiegelfrequenzen.html", + "confidence": 8 + }, + "AF205": { + "revision": 1, + "explanation": "Receiver selectivity is set by the IF filters, because nearby signals are separated after conversion to the fixed intermediate frequency.", + "source": "https://50ohm.de/A_slide_a_empfaenger.html", + "confidence": 8 + }, + "AF206": { + "revision": 1, + "explanation": "Typical receiver IF bandwidths match the mode: about 2.7 kHz for SSB speech, about 500 Hz for narrow RTTY/CW-like signals, and about 12 kHz for FM speech.", + "source": "https://50ohm.de/A_slide_a_empfaenger.html", + "confidence": 8 + }, + "AF207": { + "revision": 1, + "explanation": "The shown narrow passband is around the audio bandwidth used for SSB, much narrower than FM and not shaped for wide digital OFDM.", + "source": "https://50ohm.de/A_slide_a_empfaenger.html", + "confidence": 7 + }, + "AF208": { + "revision": 1, + "explanation": "Crystal filters can have very high Q and steep skirts, so they are best suited for narrow IF bandwidths at a given center frequency.", + "source": "https://50ohm.de/A_slide_a_empfaenger.html", + "confidence": 8 + }, + "AF209": { + "revision": 1, + "explanation": "In a double superhet, the first two conversion blocks are mixers, and the final block before audio is a product detector for SSB/CW demodulation.", + "source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html", + "confidence": 7 + }, + "AF210": { + "revision": 1, + "explanation": "For a 50 MHz first IF and a 3 to 30 MHz receive range, the VFO can use either difference mixing $50 - f_rx$ = 47 to 20 MHz or sum mixing $50 + f_rx$ = 53 to 80 MHz.", + "source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html", + "confidence": 7 + }, + "AF211": { + "revision": 1, + "explanation": "For CW, the BFO is offset from the last IF by an audible tone frequency; about 800 Hz gives a comfortable received beat note.", + "source": "https://50ohm.de/A_slide_a_empfaenger.html", + "confidence": 8 + }, + "AF212": { + "revision": 1, + "explanation": "A mixer must be nonlinear so it creates sum and difference products from the input and local oscillator frequencies.", + "source": "https://50ohm.de/A_mischer_2.html", + "confidence": 8 + }, + "AF213": { + "revision": 1, + "explanation": "A balanced mixer cancels some unwanted components such as carrier/oscillator feedthrough, so fewer unwanted output signals remain than with simple unbalanced mixers.", + "source": "https://50ohm.de/A_mischer_2.html", + "confidence": 8 + }, + "AF214": { + "revision": 1, + "explanation": "A balanced ring mixer has strong symmetry, which suppresses unwanted feedthrough and many unwanted mixer products better than simple unbalanced mixer circuits.", + "source": "https://50ohm.de/A_mischer_2.html", + "confidence": 8 + }, + "AF215": { + "revision": 1, + "explanation": "Even a temperature-compensated VFO can drift if heated unevenly, so it should be thermally isolated from power stages and other heat sources.", + "source": "https://50ohm.de/A_oszillator_tcxo_ocxo.html", + "confidence": 8 + }, + "AF216": { + "revision": 1, + "explanation": "An SSB BFO must be frequency-stable because its frequency defines the reinserted carrier position; a crystal-controlled oscillator is the stable choice.", + "source": "https://50ohm.de/A_slide_a_empfaenger.html", + "confidence": 8 + }, + "AF217": { + "revision": 1, + "explanation": "Two signals in a nonlinear receiver stage generate sum, difference, and higher-order products; that phenomenon is intermodulation.", + "source": "https://50ohm.de/A_intermodulation_kreuzmodulation.html", + "confidence": 8 + }, + "AF218": { + "revision": 1, + "explanation": "Intermodulation is caused by nonlinearity: strong input signals push the RF stage out of its linear range and create extra frequency products.", + "source": "https://50ohm.de/A_intermodulation_kreuzmodulation.html", + "confidence": 8 + }, + "AF219": { + "revision": 1, + "explanation": "Cross modulation occurs when a strong unwanted signal affects the receiver stage and transfers its modulation onto the desired signal.", + "source": "https://50ohm.de/A_intermodulation_kreuzmodulation.html", + "confidence": 8 + }, + "AF220": { + "revision": 1, + "explanation": "An input attenuator reduces the level of all incoming strong signals, keeping the receiver front end more linear and reducing intermodulation and cross modulation.", + "source": "https://50ohm.de/A_intermodulation_kreuzmodulation.html", + "confidence": 8 + }, + "AF221": { + "revision": 1, + "explanation": "IP3 is a measure of third-order intermodulation behavior, so it indicates how well the receiver handles large signals without generating distortion products.", + "source": "https://50ohm.de/A_intermodulation_kreuzmodulation.html", + "confidence": 8 + }, + "AF222": { + "revision": 1, + "explanation": "A strong nearby RF signal can overload or desensitize receiver stages, producing intermodulation or cross modulation that degrades the wanted signal.", + "source": "https://50ohm.de/A_intermodulation_kreuzmodulation.html", + "confidence": 8 + }, + "AF223": { + "revision": 1, + "explanation": "A notch or trap tuned to the unwanted signal at the receiver input can reject that interferer before it reaches the sensitive front end.", + "source": "https://50ohm.de/A_intermodulation_kreuzmodulation.html", + "confidence": 7 + }, + "AF224": { + "revision": 1, + "explanation": "AGC keeps receiver output level more constant; for strong input signals it reduces gain in receiver amplifier stages.", + "source": "https://50ohm.de/A_slide_a_empfaenger.html", + "confidence": 8 + }, + "AF225": { + "revision": 1, + "explanation": "Squelch decides whether useful modulation or carrier/noise is present by evaluating IF or audio-derived signals, then mutes or unmutes the receiver audio.", + "source": "https://50ohm.de/A_slide_a_empfaenger.html", + "confidence": 8 + }, + "AF226": { + "revision": 1, + "explanation": "In FM, information is in frequency deviation, so a limiter removes amplitude variations and suppresses AM noise before demodulation.", + "source": "https://50ohm.de/A_slide_a_empfaenger.html", + "confidence": 8 + }, + "AF227": { + "revision": 1, + "explanation": "SNR is the ratio of wanted signal power to noise power; a higher SNR means the wanted signal stands out more clearly from noise.", + "source": "https://50ohm.de/A_slide_a_empfaenger.html", + "confidence": 8 + }, + "AF228": { + "revision": 1, + "explanation": "Noise figure in dB states how much the amplifier worsens SNR; 1.8 dB means the output SNR is 1.8 dB lower than the input SNR.", + "source": "https://50ohm.de/A_slide_a_empfaenger.html", + "confidence": 8 + }, + "AF229": { + "revision": 1, + "explanation": "A noise factor of 2 corresponds to $10 log10(2) = 3 dB$, meaning the amplifier degrades the signal-to-noise ratio by 3 dB.", + "source": "https://50ohm.de/A_slide_a_empfaenger.html", + "confidence": 8 + }, + "AF230": { + "revision": 1, + "explanation": "The LNB amplifies the weak microwave signal at the antenna and converts it to a lower IF, so the long coax no longer carries the original 10 GHz signal with its high cable loss.", + "source": "https://50ohm.de/A_low_noise_block.html", + "confidence": 7 + }, + "AF231": { + "revision": 1, + "explanation": "Satellite LNBs commonly use different supply voltages to select polarization; raising the Bias-T supply to 18 V commands a polarization change.", + "source": "https://50ohm.de/A_low_noise_block.html", + "confidence": 7 + }, + "AF301": { + "revision": 1, + "explanation": "A mixer can add the 5.3 MHz signal and a 9 MHz oscillator to produce 14.3 MHz; a bandfilter then selects that desired product.", + "source": "https://50ohm.de/A_transverter_2.html", + "confidence": 8 + }, + "AF302": { + "revision": 1, + "explanation": "A balanced mixer/modulator suppresses the carrier by symmetry while leaving the two sidebands, producing DSB with suppressed carrier.", + "source": "https://50ohm.de/A_modulatoren.html", + "confidence": 8 + }, + "AF303": { + "revision": 1, + "explanation": "The usual analog SSB chain first creates DSB with a balanced modulator, then a sideband filter passes only one of the two sidebands.", + "source": "https://50ohm.de/A_modulatoren.html", + "confidence": 8 + }, + "AF304": { + "revision": 1, + "explanation": "Analog SSB generation suppresses the carrier in the balanced modulator and removes the unwanted sideband with a filter.", + "source": "https://50ohm.de/A_modulatoren.html", + "confidence": 8 + }, + "AF305": { + "revision": 1, + "explanation": "After the balanced modulator has made DSB, the marked filter must be a narrow bandpass, commonly a crystal filter, that selects the desired sideband.", + "source": "https://50ohm.de/A_modulatoren.html", + "confidence": 7 + }, + "AF306": { + "revision": 1, + "explanation": "The block after the audio amplifier multiplies the audio with the carrier oscillator; in an SSB transmitter that function is the balanced mixer/modulator.", + "source": "https://50ohm.de/A_modulatoren.html", + "confidence": 7 + }, + "AF307": { + "revision": 1, + "explanation": "The USB carrier frequency is symmetric to the LSB carrier around the 9 MHz filter center: $9.0000 MHz - (9.0015 - 9.0000) MHz = 8.9985 MHz$.", + "source": "https://50ohm.de/A_modulatoren.html", + "confidence": 7 + }, + "AF308": { + "revision": 1, + "explanation": "The balanced diode modulator cancels the carrier and leaves the modulation sidebands, so it generates AM with suppressed carrier.", + "source": "https://50ohm.de/A_modulatoren.html", + "confidence": 7 + }, + "AF309": { + "revision": 1, + "explanation": "The balancing network trims amplitude and phase so the carrier components cancel as well as possible in the balanced modulator.", + "source": "https://50ohm.de/A_modulatoren.html", + "confidence": 7 + }, + "AF310": { + "revision": 1, + "explanation": "The diode is a varicap in the oscillator tank; the audio voltage changes its capacitance, shifting the resonant frequency and producing FM.", + "source": "https://50ohm.de/A_modulatoren.html", + "confidence": 7 + }, + "AF311": { + "revision": 1, + "explanation": "Analog frequency multiplication deliberately drives a nonlinear stage to create harmonics, then filters out the desired harmonic frequency.", + "source": "https://50ohm.de/A_frequenzvervielfacher_2.html", + "confidence": 8 + }, + "AF312": { + "revision": 1, + "explanation": "The stage is biased and tuned to use distortion harmonics rather than linear amplification, which identifies it as a frequency multiplier.", + "source": "https://50ohm.de/A_frequenzvervielfacher_2.html", + "confidence": 7 + }, + "AF313": { + "revision": 1, + "explanation": "Frequency multipliers intentionally generate harmonics, including unwanted ones, so shielding is important to prevent those signals from being radiated.", + "source": "https://50ohm.de/A_frequenzvervielfacher_2.html", + "confidence": 8 + }, + "AF314": { + "revision": 1, + "explanation": "Only the sequence $12 MHz x 2 x 2 x 3 x 3$ passes through 144 MHz as an intermediate result: 24 MHz, 48 MHz, 144 MHz, then 432 MHz.", + "source": "https://50ohm.de/A_frequenzvervielfacher_2.html", + "confidence": 8 + }, + "AF401": { + "revision": 1, + "explanation": "HF amplifier efficiency is useful RF output power divided by the DC power taken from the supply.", + "source": "https://50ohm.de/A_verstaerker_wirkungsgrad.html", + "confidence": 8 + }, + "AF402": { + "revision": 1, + "explanation": "Class C conducts for less than half the RF cycle, making it highly nonlinear and therefore rich in harmonics.", + "source": "https://50ohm.de/A_verstaerker_klasse.html", + "confidence": 8 + }, + "AF403": { + "revision": 1, + "explanation": "Class C stages and their output networks can contain strong harmonics, so the matching and filtering circuits should be enclosed in a shielded metal housing.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 8 + }, + "AF404": { + "revision": 1, + "explanation": "An LC output network transforms the PA output impedance to the antenna impedance and, because it is frequency-selective, also attenuates harmonics.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 8 + }, + "AF405": { + "revision": 1, + "explanation": "A pi output filter acts as an impedance transformer and a low-pass network, so it improves matching while suppressing harmonics.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 8 + }, + "AF406": { + "revision": 1, + "explanation": "The marked output network is the matching section; it transforms the external load impedance to the impedance the transistor stage needs.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF407": { + "revision": 1, + "explanation": "The marked input matching parts transform the previous stage's output impedance to the transistor's required input impedance for proper drive.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF408": { + "revision": 1, + "explanation": "The tuned resonant circuits in the RF signal path make the stage frequency-selective, so it is a selective RF amplifier rather than a broadband or audio amplifier.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF409": { + "revision": 1, + "explanation": "A tapped resonant circuit can provide impedance transformation, letting the preceding stage drive the tuned amplifier input at a suitable impedance point.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF410": { + "revision": 1, + "explanation": "C1 and C2 are part of the matching network, setting the impedance transformation between the transistor stage and the connected circuit.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF411": { + "revision": 1, + "explanation": "The marked supply decoupling path gives RF a low-impedance route to ground, preventing RF from entering the DC supply line.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF412": { + "revision": 1, + "explanation": "The push-pull transformer-coupled layout is intended for broadband RF amplification rather than a narrow tuned stage, so it is a broadband push-pull amplifier.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF413": { + "revision": 1, + "explanation": "The two cascaded broadband transformer-coupled stages identify the circuit as a two-stage broadband RF amplifier.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF414": { + "revision": 1, + "explanation": "The transformer couples stages while transforming the output impedance of one emitter stage to the input impedance of the following emitter stage.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF415": { + "revision": 1, + "explanation": "Large capacitors are effective at low frequencies but poorer at very high RF; small capacitors keep low impedance at high frequencies, so the parallel pair decouples over a wider range.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF416": { + "revision": 1, + "explanation": "The resistor damps the transformer winding, reducing excessive Q and helping prevent parasitic oscillations.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF417": { + "revision": 1, + "explanation": "The transformers provide broadband impedance transformation between the 50 ohm system and the low transistor input and output impedances.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF418": { + "revision": 1, + "explanation": "An inductor in series with shunt capacitors forms an LC low-pass section: it passes DC/low-frequency supply current but diverts RF to ground.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF419": { + "revision": 1, + "explanation": "The choke and bypass capacitors form supply-line filtering, reducing RF components on the DC supply line rather than filtering the transmitted RF path itself.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF420": { + "revision": 1, + "explanation": "Moving R3 toward position 3 lowers the gate bias for both LDMOS devices in the DC equivalent circuit, so both drain currents decrease.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF421": { + "revision": 1, + "explanation": "For DC bias, the gates draw negligible current and the resistor network acts as a voltage divider; at stop 1 the divider sets the gate-source voltage to 3.5 V.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF422": { + "revision": 1, + "explanation": "The coils are RF chokes in the supply feeds; they pass DC but present high impedance to RF, keeping RF out of the supply line.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF423": { + "revision": 1, + "explanation": "Increasing LDMOS quiescent current means raising both gate-bias voltages, so both bias controls are moved toward UBIAS.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF424": { + "revision": 1, + "explanation": "R4 affects only the bias path for transistor 1 in the shown circuit; moving its wiper toward UBIAS raises that gate bias and drain current, while transistor 2 is unchanged.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF425": { + "revision": 1, + "explanation": "The resistor must drop $13.5 V - 4 V = 9.5 V$ at 10 mA, so $R = 9.5 V / 0.010 A = 950 ohm$.", + "source": "https://50ohm.de/A_integrierte_schaltkreise.html", + "confidence": 7 + }, + "AF426": { + "revision": 1, + "explanation": "The bias resistor drops $13.8 V - 4 V = 9.8 V$ at 15 mA; $9.8 V / 0.015 A = 653 ohm$, so the nearest listed standard value is 680 ohm.", + "source": "https://50ohm.de/A_integrierte_schaltkreise.html", + "confidence": 7 + }, + "AF427": { + "revision": 1, + "explanation": "With a 4 V MMIC drop, the resistor current is $(9 V - 4 V) / 470 ohm = 10.6 mA$; MMIC heat is $4 V x 10.6 mA = 42.6 mW$, about 43 mW.", + "source": "https://50ohm.de/A_integrierte_schaltkreise.html", + "confidence": 7 + }, + "AF428": { + "revision": 1, + "explanation": "Overall gain in dB is the output level minus the input level in dBm; the diagram's level difference is 48 dB when cable losses are ignored.", + "source": "https://50ohm.de/NEA_leistungsvertaerker.html", + "confidence": 7 + }, + "AF501": { + "revision": 1, + "explanation": "The converter uses the 9th harmonic of the crystal oscillator and maps the 436 to 440 MHz range to 28 to 30 MHz, so $f_Q = (f_rx - f_IF) / 9$ gives 45.333 MHz and 45.556 MHz.", + "source": "https://50ohm.de/A_transverter_2.html", + "confidence": 7 + }, + "AF502": { + "revision": 1, + "explanation": "For the lower 70 cm segment, the same conversion maps 430 to 434 MHz down to 28 to 30 MHz using the 9th harmonic, so $(430 - 28) / 9 = 44.667 MHz$ and $(434 - 30) / 9 = 44.889 MHz$.", + "source": "https://50ohm.de/A_transverter_2.html", + "confidence": 7 + }, "BA101": { "revision": 2, "explanation": "DD4UQ spells D as Delta, U as Uniform and Q as Quebec; the traps are country-style words such as Denmark, Uruguay and Queen, which are not the ITU code words.",