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Correct AnswerThe entire cycle
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Exactly 180 degrees
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More than 180 degrees but less than 360 degrees
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Less than 180 degrees
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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Correct AnswerClass A
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Class AB
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Class B
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Class C
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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Exactly 180 degrees
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The entire cycle
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Less than 180 degrees
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Correct AnswerMore than 180 degrees but less than 360 degrees
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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Correct Answer180 degrees
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Less than 180 degrees
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More than 180 degrees but less than 360 degrees
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The entire cycle
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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The entire cycle
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180 degrees
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Correct AnswerLess than 180 degrees
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More than 180 degrees but less than 360 degrees
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 B
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Correct AnswerClass C
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Class A
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Class AB
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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Correct AnswerClass C
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Class AB
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Class B
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Class A
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 AB
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Correct AnswerClass A
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Class C
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Class B
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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Correct AnswerClass C
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Class AB
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Class A
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Class B
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 B
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Class C
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Correct AnswerClass A
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Class AB
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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Correct AnswerClass C
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Class AB
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Class A
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Class B
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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The input impedance is essentially determined by the resistance between the drain and substrate
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Correct AnswerThe input impedance is essentially determined by the gate biasing network
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The input impedance is essentially determined by the resistance between the source and substrate
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The input impedance is essentially determined by the resistance between the source and the drain
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.
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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Correct AnswerThe output impedance is essentially determined by the drain resistor
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The output impedance is essentially determined by the drain supply voltage
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The output impedance is essentially determined by the gate supply voltage
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The output impedance is essentially determined by the input impedance of the FET
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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Mutual gain, low input impedance and low output impedance
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Low output impedance, high mutual impedance and low output current
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Correct AnswerHigh gain, high input impedance and low output impedance
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Mutual gain, high stability and low mutual inductance
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.
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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the signals are 180 degrees out of phase
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Correct Answerthe signals are in phase
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the output signal lags the input signal by 90 degrees
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the output signals leads the input signal by 90 degrees
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.
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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only slightly lower
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very high
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Correct Answervery low
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only slightly higher
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.
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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the output signal leads the input signal by 90 degrees
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the output signal lags the input signal by 90 degrees
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the signals are in phase
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Correct Answerthe signals are 180 degrees out of phase
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.
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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Correct Answerthe signals are in phase
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the output signal leads the input signal by 90 degrees
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the output signal lags the input signal by 90 degrees
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the signals are 180 degrees out of phase
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.
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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common mode circuit
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common gate circuit
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Correct Answercommon drain circuit
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common source circuit
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.
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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Correct AnswerCommon emitter
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Common collector
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Common base
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Common mode
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Common mode
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Correct AnswerCommon collector
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Common emitter
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Common base
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Common emitter
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Correct AnswerCommon base
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Common mode
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Common collector
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An amplifier used to increase the average output of frequency modulated amateur signals to the legal limit
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A program subroutine that calculates the gain of an RF amplifier
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Correct AnswerA high-gain, direct-coupled differential amplifier whose characteristics are determined by components mounted externally
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A high-gain, direct-coupled audio amplifier whose characteristics are determined by internal components of the device
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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Zero input impedance, zero output impedance, infinite gain, and flat frequency response
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Infinite input impedance, infinite output impedance, infinite gain and flat frequency response
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Zero input impedance, infinite output impedance, infinite gain, and flat frequency response
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Correct AnswerInfinite input impedance, zero output impedance, infinite gain, and flat frequency response
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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The voltage applied to the circuit
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The collector-to-base capacitance of the PNP stage
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Correct AnswerThe external feedback network
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The PNP collector load
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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The difference between the output voltage of the op-amp and the input voltage required for the next stage
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The potential between the amplifier input terminals of the op-amp in an open-loop condition
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The output voltage of the op-amp minus its input voltage
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Correct AnswerThe potential between the amplifier input terminals of the op-amp in a closed-loop condition
"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)".
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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Correct AnswerVery high
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Very low
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Exactly 100 ohms
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Exactly 1000 ohms
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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Very high
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Exactly 100 ohms
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Exactly 1000 ohms
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Correct AnswerVery low
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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Op-amps are more rugged and can withstand more abuse than can LC elements
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Op-amps are available in more styles and types than are LC elements
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Op-amps are fixed at one frequency
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Correct AnswerOp-amps exhibit gain rather than insertion loss
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).
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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Op-amp circuits are used as low-pass filters at the output of transmitters
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Op-amp circuits are used as filters for smoothing power supply output
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Op-amp circuits are used as high-pass filters to block RFI at the input of receivers
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Correct AnswerOp-amp circuits are used as audio filters for receivers
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).
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 circuit connected such that the input impedance is held to zero, while the output impedance is high
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Correct AnswerAn operational amplifier circuit connected such that the input and output signals are 180 degrees out of phase
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An operational amplifier circuit connected such that the input and output signals are in phase
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An operational amplifier circuit connected such that the input and output signals are 90 degrees out of phase
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 circuit connected such that the input and output signals are 90 degrees out of phase
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An operational amplifier circuit connected such that the input impedance is held low, and the output impedance is high
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An operational amplifier circuit connected such that the input and output signals are 180 degrees out of phase
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Correct AnswerAn operational amplifier circuit connected such that the input and output signals are in phase
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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Summing amplifier
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Correct AnswerOperational amplifier
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Difference amplifier
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High gain audio amplifier
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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The recovery of intelligence from a modulated signal
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The elimination of noise in a wideband receiver by phase comparison
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Correct AnswerThe combination of two signals to produce sum and difference frequencies
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The elimination of noise in a wideband receiver by phase differentiation
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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Correct AnswerThe original frequencies and the sum and difference frequencies
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1.414 and 0.707 times the input frequencies
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The sum, difference and square root of the input frequencies
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Two and four times the original frequency
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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Mixer blanking occurs
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Correct AnswerSpurious signals are generated
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Automatic limiting occurs
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A beat frequency is generated
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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part of the input tuned circuit
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a by-pass for the circuit
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part of the output tank circuit
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Correct Answera DC blocking capacitor
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.
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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Correct Answertune L1 to the desired harmonic
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by-pass RF
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tune L1 to the frequency applied to the base
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provide positive feedback
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resonate with L1
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by-pass any audio components
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Correct Answerprovide an RF ground at the VCC connection point of L1
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form a pi filter with L1 and C2
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.
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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voltage doubler
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Correct Answerfrequency multiplier
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frequency divider
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voltage divider
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a frequency divider
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Correct Answera frequency multiplier
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a VHF/UHF amplifier
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a linear amplifier
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.
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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DC blocking capacitor
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tuning capacitor
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coupling capacitor
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Correct AnswerRF by-pass capacitor
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.
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 frequency multiplier
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A beat frequency oscillator
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Correct AnswerA mixer
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A linear translator
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.
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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freedom from harmonic emissions
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simplicity
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Correct Answermuch greater frequency stability
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longer life under severe operating use
Piezoelectric crystals behave like tuned circuits with an extremely high "Q" ("Quality Factor", in excess of 25 000). Their accuracy and stability are outstanding.
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 crystal ladder
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Correct Answeran overtone oscillator
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a crystal multiplier
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a crystal lattice
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.
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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Good frequency accuracy
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Correct AnswerHigh power output
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Good frequency stability
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Very low noise because of high Q
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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