Class A: 360 degrees, best linearity, least distortion, poor efficiency [25 to 30%]. Class AB: significantly more than 180 but less than 360 degrees, very acceptable linearity, medium efficiency [50 to 60%]. Class B: 180 degrees, acceptable linearity, medium efficiency [up to 65%]. Class C: much less than 180 degrees, poor linearity, high distortion, best efficiency [up to 80%]. Usable with constant amplitude signals (CW,FM) where 'flywheel' effect in tank circuit maintains the waveform. Harmonic-rich output is useful in frequency multiplier.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
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Class A: 360 degrees, best linearity, least distortion, poor efficiency [25 to 30%]. Class AB: significantly more than 180 but less than 360 degrees, very acceptable linearity, medium efficiency [50 to 60%]. Class B: 180 degrees, acceptable linearity, medium efficiency [up to 65%]. Class C: much less than 180 degrees, poor linearity, high distortion, best efficiency [up to 80%]. Usable with constant amplitude signals (CW,FM) where 'flywheel' effect in tank circuit maintains the waveform. Harmonic-rich output is useful in frequency multiplier.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
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Class A: 360 degrees, best linearity, least distortion, poor efficiency [25 to 30%]. Class AB: significantly more than 180 but less than 360 degrees, very acceptable linearity, medium efficiency [50 to 60%]. Class B: 180 degrees, acceptable linearity, medium efficiency [up to 65%]. Class C: much less than 180 degrees, poor linearity, high distortion, best efficiency [up to 80%]. Usable with constant amplitude signals (CW,FM) where 'flywheel' effect in tank circuit maintains the waveform. Harmonic-rich output is useful in frequency multiplier.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
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Class A: 360 degrees, best linearity, least distortion, poor efficiency [25 to 30%]. Class AB: significantly more than 180 but less than 360 degrees, very acceptable linearity, medium efficiency [50 to 60%]. Class B: 180 degrees, acceptable linearity, medium efficiency [up to 65%]. Class C: much less than 180 degrees, poor linearity, high distortion, best efficiency [up to 80%]. Usable with constant amplitude signals (CW,FM) where 'flywheel' effect in tank circuit maintains the waveform. Harmonic-rich output is useful in frequency multiplier.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
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Class A: 360 degrees, best linearity, least distortion, poor efficiency [25 to 30%]. Class AB: significantly more than 180 but less than 360 degrees, very acceptable linearity, medium efficiency [50 to 60%]. Class B: 180 degrees, acceptable linearity, medium efficiency [up to 65%]. Class C: much less than 180 degrees, poor linearity, high distortion, best efficiency [up to 80%]. Usable with constant amplitude signals (CW,FM) where 'flywheel' effect in tank circuit maintains the waveform. Harmonic-rich output is useful in frequency multiplier.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
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Class A: 360 degrees, best linearity, least distortion, poor efficiency [25 to 30%]. Class AB: significantly more than 180 but less than 360 degrees, very acceptable linearity, medium efficiency [50 to 60%]. Class B: 180 degrees, acceptable linearity, medium efficiency [up to 65%]. Class C: much less than 180 degrees, poor linearity, high distortion, best efficiency [up to 80%]. Usable with constant amplitude signals (CW,FM) where 'flywheel' effect in tank circuit maintains the waveform. Harmonic-rich output is useful in frequency multiplier.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
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Class A: 360 degrees, best linearity, least distortion, poor efficiency [25 to 30%]. Class AB: significantly more than 180 but less than 360 degrees, very acceptable linearity, medium efficiency [50 to 60%]. Class B: 180 degrees, acceptable linearity, medium efficiency [up to 65%]. Class C: much less than 180 degrees, poor linearity, high distortion, best efficiency [up to 80%]. Usable with constant amplitude signals (CW,FM) where 'flywheel' effect in tank circuit maintains the waveform. Harmonic-rich output is useful in frequency multiplier.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
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Class A: 360 degrees, best linearity, least distortion, poor efficiency [25 to 30%]. Class AB: significantly more than 180 but less than 360 degrees, very acceptable linearity, medium efficiency [50 to 60%]. Class B: 180 degrees, acceptable linearity, medium efficiency [up to 65%]. Class C: much less than 180 degrees, poor linearity, high distortion, best efficiency [up to 80%]. Usable with constant amplitude signals (CW,FM) where 'flywheel' effect in tank circuit maintains the waveform. Harmonic-rich output is useful in frequency multiplier.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
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Class A: 360 degrees, best linearity, least distortion, poor efficiency [25 to 30%]. Class AB: significantly more than 180 but less than 360 degrees, very acceptable linearity, medium efficiency [50 to 60%]. Class B: 180 degrees, acceptable linearity, medium efficiency [up to 65%]. Class C: much less than 180 degrees, poor linearity, high distortion, best efficiency [up to 80%]. Usable with constant amplitude signals (CW,FM) where 'flywheel' effect in tank circuit maintains the waveform. Harmonic-rich output is useful in frequency multiplier.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
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Class A: 360 degrees, best linearity, least distortion, poor efficiency [25 to 30%]. Class AB: significantly more than 180 but less than 360 degrees, very acceptable linearity, medium efficiency [50 to 60%]. Class B: 180 degrees, acceptable linearity, medium efficiency [up to 65%]. Class C: much less than 180 degrees, poor linearity, high distortion, best efficiency [up to 80%]. Usable with constant amplitude signals (CW,FM) where 'flywheel' effect in tank circuit maintains the waveform. Harmonic-rich output is useful in frequency multiplier.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
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Class A: 360 degrees, best linearity, least distortion, poor efficiency [25 to 30%]. Class AB: significantly more than 180 but less than 360 degrees, very acceptable linearity, medium efficiency [50 to 60%]. Class B: 180 degrees, acceptable linearity, medium efficiency [up to 65%]. Class C: much less than 180 degrees, poor linearity, high distortion, best efficiency [up to 80%]. Usable with constant amplitude signals (CW,FM) where 'flywheel' effect in tank circuit maintains the waveform. Harmonic-rich output is useful in frequency multiplier.
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The Junction FET is considered a high impedance device. Because the Gate in a Junction FET is always reversed-biased, its input impedance is very high; the input impedance of the whole circuit is determined by the external Gate bias resistor. The output impedance is determined primarily by the resistor acting as a load in the Drain circuit.
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The Junction FET is considered a high impedance device. Because the Gate in a Junction FET is always reversed-biased, its input impedance is very high; the input impedance of the whole circuit is determined by the external Gate bias resistor. The output impedance is determined primarily by the resistor acting as a load in the Drain circuit.
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The Darlington pair cascades two direct-coupled emitter-follower stages; Beta parameters multiply one another. The emitter follower, just like the cathode follower or the source follower features high input impedance and low output impedance. The Darlington configuration features high gain, high input impedance and low output impedance. "High gain" is enough to identify the correct answer.
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Common Emitter: low input Z, medium output Z, 180-degrees phase shift. Common Base: very low input Z, high output Z, no phase shift. Common Collector (Common Drain, Common Plate): high input Z, low output Z, no phase shift, also known as Emitter (Source, Cathode) follower, used for isolation or impedance matching.
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Common Emitter: low input Z, medium output Z, 180-degrees phase shift. Common Base: very low input Z, high output Z, no phase shift. Common Collector (Common Drain, Common Plate): high input Z, low output Z, no phase shift, also known as Emitter (Source, Cathode) follower, used for isolation or impedance matching.
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Common Emitter: low input Z, medium output Z, 180-degrees phase shift. Common Base: very low input Z, high output Z, no phase shift. Common Collector (Common Drain, Common Plate): high input Z, low output Z, no phase shift, also known as Emitter (Source, Cathode) follower, used for isolation or impedance matching.
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Common Emitter: low input Z, medium output Z, 180-degrees phase shift. Common Base: very low input Z, high output Z, no phase shift. Common Collector (Common Drain, Common Plate): high input Z, low output Z, no phase shift, also known as Emitter (Source, Cathode) follower, used for isolation or impedance matching.
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In a source follower stage, the Source constitutes the output; the Drain, by opposition, must be tied to a common reference (a zero reference for signals): hence the expression, common drain.
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An Operational Amplifier is a high gain, direct-coupled differential amplifier whose characteristics are determined mainly by external components. For example, circuit gain is determined by the feedback network from output to input. The "ideal" Op-Amp would have infinite gain, infinite bandwidth (i.e., constant gain at any frequency), infinite input impedance and zero output impedance.
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An Operational Amplifier is a high gain, direct-coupled differential amplifier whose characteristics are determined mainly by external components. For example, circuit gain is determined by the feedback network from output to input. The "ideal" Op-Amp would have infinite gain, infinite bandwidth (i.e., constant gain at any frequency), infinite input impedance and zero output impedance.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
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An Operational Amplifier is a high gain, direct-coupled differential amplifier whose characteristics are determined mainly by external components. For example, circuit gain is determined by the feedback network from output to input. The "ideal" Op-Amp would have infinite gain, infinite bandwidth (i.e., constant gain at any frequency), infinite input impedance and zero output impedance.
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"Offset voltage is the potential between the amplifier input terminals in the closed-loop condition. Ideally, this voltage would be zero. Offset results from imbalance between the differential input transistors (ARRL Handbook)".
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An Operational Amplifier is a high gain, direct-coupled differential amplifier whose characteristics are determined mainly by external components. For example, circuit gain is determined by the feedback network from output to input. The "ideal" Op-Amp would have infinite gain, infinite bandwidth (i.e., constant gain at any frequency), infinite input impedance and zero output impedance.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
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An Operational Amplifier is a high gain, direct-coupled differential amplifier whose characteristics are determined mainly by external components. For example, circuit gain is determined by the feedback network from output to input. The "ideal" Op-Amp would have infinite gain, infinite bandwidth (i.e., constant gain at any frequency), infinite input impedance and zero output impedance.
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Inductors and Capacitors are passive components; they inevitably introduce loss. Op-Amps used in filter applications can provide a controlled amount of gain. Op-Amps are commonly used in active AUDIO filter circuits; all types of responses can be implemented (low-pass, high-pass, bandpass, band-stop, a.k.a., notch).
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Inductors and Capacitors are passive components; they inevitably introduce loss. Op-Amps used in filter applications can provide a controlled amount of gain. Op-Amps are commonly used in active AUDIO filter circuits; all types of responses can be implemented (low-pass, high-pass, bandpass, band-stop, a.k.a., notch).
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An "inverting" Op-Amp circuit introduces a 180-degrees shift: when the input goes up, the output comes down and vice-versa. With the "non-inverting" Op-Amp circuit, the output is in phase with the input.
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An "inverting" Op-Amp circuit introduces a 180-degrees shift: when the input goes up, the output comes down and vice-versa. With the "non-inverting" Op-Amp circuit, the output is in phase with the input.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
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An Operational Amplifier is a high gain, direct-coupled differential amplifier whose characteristics are determined mainly by external components. For example, circuit gain is determined by the feedback network from output to input. The "ideal" Op-Amp would have infinite gain, infinite bandwidth (i.e., constant gain at any frequency), infinite input impedance and zero output impedance.
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A Mixer receives two inputs. They combine within the Mixer to produce two new frequencies: the sum of the inputs and the difference between the inputs. Four frequencies are present at the output: the sum, the difference and the two original frequencies. If a Mixer is driven into non-linearity by excessively strong signals, spurious responses will be produced.
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A Mixer receives two inputs. They combine within the Mixer to produce two new frequencies: the sum of the inputs and the difference between the inputs. Four frequencies are present at the output: the sum, the difference and the two original frequencies. If a Mixer is driven into non-linearity by excessively strong signals, spurious responses will be produced.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
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A Mixer receives two inputs. They combine within the Mixer to produce two new frequencies: the sum of the inputs and the difference between the inputs. Four frequencies are present at the output: the sum, the difference and the two original frequencies. If a Mixer is driven into non-linearity by excessively strong signals, spurious responses will be produced.
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A Frequency-Multiplier stage relies on harmonics produced by a gain device operated in Class C. The output circuit is tuned to an exact multiple of the input frequency (harmonic, typically two to four times). If greater multiplication is required, a chain of stages will be used.
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A capacitor between the supply and ground is a "bypass" capacitor, it serves two purposes: it provides a low-impedance path to complete the AC circuit and it keeps AC signals out of the supply line (through which they could affect other stages). This being a frequency multiplier, the capacitor is an RF bypass.
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A Frequency-Multiplier stage relies on harmonics produced by a gain device operated in Class C. The output circuit is tuned to an exact multiple of the input frequency (harmonic, typically two to four times). If greater multiplication is required, a chain of stages will be used.
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A capacitor between the supply and ground is a "bypass" capacitor, it serves two purposes: it provides a low-impedance path to complete the AC circuit and it keeps AC signals out of the supply line (through which they could affect other stages). This being a frequency multiplier, the capacitor is an RF bypass.
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The second frequency is not a multiple of the first, this excludes the multiplier. A Frequency Multiplier stage relies on harmonics produced by a gain device operated in Class C. The output circuit is tuned to an exact multiple of the input frequency (harmonic, typically two to four times). If greater multiplication is required, a chain of stages will be used.
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Piezoelectric crystals behave like tuned circuits with an extremely high "Q" ("Quality Factor", in excess of 25 000). Their accuracy and stability are outstanding.
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Key word: MULTIPLE. Crystals are capable of resonance either at a fundamental frequency depending on their physical dimensions or at overtone frequencies near odd-integer multiples (3rd, 5th, 7th, etc.) of the fundamental. In a filter, crystals are used at their fundamental frequencies; the crystal lattice filter and the crystal ladder filter are two typical configurations. Crystal oscillators can be designed to work on a fundamental or overtone resonance; crystals are manufactured accordingly.
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The piezoelectric property of quartz is two-fold: apply mechanical stress to a crystal and it produces a small electrical field; subject quartz to an electrical field and the crystal changes dimensions slightly. Crystals are capable of resonance either at a fundamental frequency depending on their physical dimensions or at overtone frequencies near odd-integer multiples (3rd, 5th, 7th, etc.). Piezoelectric crystals can serve as filters because of their extremely high "Q" (> 25 000) or as stable, noise-free and accurate frequency references.
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