G7 - PRACTICAL CIRCUITS [3 Exam Questions 3 Groups] Flashcards by Emanuel Tsarnas

What safety feature does a power-supply bleeder resistor provide?

A. It acts as a fuse for excess voltage

B. It discharges the filter capacitors

C. It removes shock hazards from the induction coils

D. It eliminates ground-loop current

B. It discharges the filter capacitors

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Which of the following components are used in a power-supply filter network?

A. Diodes

B. Transformers and transducers

C. Quartz crystals

D. Capacitors and inductors

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What is the peak-inverse-voltage across the rectifiers in a full-wave bridge power supply?

A. One-quarter the normal output voltage of the power supply

B. Half the normal output voltage of the power supply

C. Double the normal peak output voltage of the power supply

D. Equal to the normal peak output voltage of the power supply

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What is the peak-inverse-voltage across the rectifier in a half-wave power supply?

A. One-half the normal peak output voltage of the power supply

B. One-half the normal output voltage of the power supply

C. Equal to the normal output voltage of the power supply

D. Two times the normal peak output voltage of the power supply

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What portion of the AC cycle is converted to DC by a half-wave rectifier?

A. 90 degrees

B. 180 degrees

C. 270 degrees

D. 360 degrees

B. 180 degrees

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What portion of the AC cycle is converted to DC by a full-wave rectifier?

A. 90 degrees

B. 180 degrees

C. 270 degrees

D. 360 degrees

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What is the output waveform of an unfiltered full-wave rectifier connected to a resistive load?

A. A series of DC pulses at twice the frequency of the AC input

B. A series of DC pulses at the same frequency as the AC input

C. A sine wave at half the frequency of the AC input

D. A steady DC voltage

A. A series of DC pulses at twice the frequency of the AC input

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Which of the following is an advantage of a switch-mode power supply as compared to a linear power supply?

A. Faster switching time makes higher output voltage possible

B. Fewer circuit components are required

C. High frequency operation allows the use of smaller components

D. All of these choices are correct

C. High frequency operation allows the use of smaller components

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Which symbol in figure G7-1 represents a field effect transistor?

A. Symbol 2

B. Symbol 5

C. Symbol 1

D. Symbol 4

C. Symbol 1

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Which symbol in figure G7-1 represents a Zener diode?

A. Symbol 4

B. Symbol 1

C. Symbol 11

D. Symbol 5

D. Symbol 5

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Which symbol in figure G7-1 represents an NPN junction transistor?

A. Symbol 1

B. Symbol 2

C. Symbol 7

D. Symbol 11

B. Symbol 2

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Which symbol in Figure G7-1 represents a multiple-winding transformer?

A. Symbol 4

B. Symbol 7

C. Symbol 6

D. Symbol 1

C. Symbol 6

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Which symbol in Figure G7-1 represents a tapped inductor?

A. Symbol 7

B. Symbol 11

C. Symbol 6

D. Symbol 1

A. Symbol 7

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Complex digital circuitry can often be replaced by what type of integrated circuit?

A. Microcontroller

B. Charge-coupled device

C. Phase detector

D. Window comparator

A. Microcontroller

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Which of the following is an advantage of using the binary system when processing digital signals?

A. Binary “ones” and “zeros” are easy to represent with an “on” or “off” state

B. The binary number system is most accurate

C. Binary numbers are more compatible with analog circuitry

D. All of these choices are correct

A. Binary “ones” and “zeros” are easy to represent with an “on” or “off” state

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Which of the following describes the function of a two input AND gate?

A. Output is high when either or both inputs are low

B. Output is high only when both inputs are high

C. Output is low when either or both inputs are high

D. Output is low only when both inputs are high

B. Output is high only when both inputs are high

Which of the following describes the function of a two input NOR gate?

A. Output is high when either or both inputs are low

B. Output is high only when both inputs are high

C. Output is low when either or both inputs are high

D. Output is low only when both inputs are high

C. Output is low when either or both inputs are high

How many states does a 3-bit binary counter have?

A. 3

B. 6

C. 8

D. 16

C. 8

What is a shift register?

A. A clocked array of circuits that passes data in steps along the array

B. An array of operational amplifiers used for tri state arithmetic operations

C. A digital mixer

D. An analog mixer

A. A clocked array of circuits that passes data in steps along the array

What are the basic components of virtually all sine wave oscillators?

A. An amplifier and a divider

B. A frequency multiplier and a mixer

C. A circulator and a filter operating in a feed-forward loop

D. A filter and an amplifier operating in a feedback loop

How is the efficiency of an RF power amplifier determined?

A. Divide the DC input power by the DC output power

B. Divide the RF output power by the DC input power

C. Multiply the RF input power by the reciprocal of the RF output power

D. Add the RF input power to the DC output power

B. Divide the RF output power by the DC input power

What determines the frequency of an LC oscillator?

A. The number of stages in the counter

B. The number of stages in the divider

C. The inductance and capacitance in the tank circuit

D. The time delay of the lag circuit

C. The inductance and capacitance in the tank circuit

Which of the following is a characteristic of a Class A amplifier?

A. Low standby power

B. High Efficiency

C. No need for bias

D. Low distortion

For which of the following modes is a Class C power stage appropriate for amplifying a modulated signal?

A. SSB

B. CW

C. AM

D. All of these choices are correct

B. CW

Which of these classes of amplifiers has the highest efficiency? A. Class A B. Class B C. Class AB D. Class C

D. Class C

What is the reason for neutralizing the final amplifier stage of a transmitter? A. To limit the modulation index B. To eliminate self-oscillations C. To cut off the final amplifier during standby periods D. To keep the carrier on frequency

B. To eliminate self-oscillations

Which of the following describes a linear amplifier? A. Any RF power amplifier used in conjunction with an amateur transceiver B. An amplifier in which the output preserves the input waveform C. A Class C high efficiency amplifier D. An amplifier used as a frequency multiplier

B. An amplifier in which the output preserves the input waveform

Which of the following is used to process signals from the balanced modulator and send them to the mixer in a single-sideband phone transmitter? A. Carrier oscillator B. Filter C. IF amplifier D. RF amplifier

B. Filter

Which circuit is used to combine signals from the carrier oscillator and speech amplifier and send the result to the filter in a typical single-sideband phone transmitter? A. Discriminator B. Detector C. IF amplifier D. Balanced modulator

D. Balanced modulator

What circuit is used to process signals from the RF amplifier and local oscillator and send the result to the IF filter in a superheterodyne receiver? A. Balanced modulator B. IF amplifier C. Mixer D. Detector

C. Mixer

What circuit is used to combine signals from the IF amplifier and BFO and send the result to the AF amplifier in a single-sideband receiver? A. RF oscillator B. IF filter C. Balanced modulator D. Product detector

D. Product detector

Which of the following is an advantage of a transceiver controlled by a direct digital synthesizer (DDS)? A. Wide tuning range and no need for band switching B. Relatively high power output C. Relatively low power consumption D. Variable frequency with the stability of a crystal oscillator

D. Variable frequency with the stability of a crystal oscillator

What should be the impedance of a low-pass filter as compared to the impedance of the transmission line into which it is inserted? A. Substantially higher B. About the same C. Substantially lower D. Twice the transmission line impedance

B. About the same

What is the simplest combination of stages that implement a superheterodyne receiver? A. RF amplifier, detector, audio amplifier B. RF amplifier, mixer, IF discriminator C. HF oscillator, mixer, detector D. HF oscillator, pre-scaler, audio amplifier

C. HF oscillator, mixer, detector

What type of circuit is used in many FM receivers to convert signals coming from the IF amplifier to audio? A. Product detector B. Phase inverter C. Mixer D. Discriminator

D. Discriminator

Which of the following is needed for a Digital Signal Processor IF filter? A. An analog to digital converter B. A digital to analog converter C. A digital processor chip D. All of the these choices are correct

D. All of the these choices are correct

How is Digital Signal Processor filtering accomplished? A. By using direct signal phasing B. By converting the signal from analog to digital and using digital processing C. By differential spurious phasing D. By converting the signal from digital to analog and taking the difference of mixing products

B. By converting the signal from analog to digital and using digital processing

What is meant by the term "software defined radio" (SDR)? A. A radio in which most major signal processing functions are performed by software B. A radio which provides computer interface for automatic logging of band and frequency C. A radio which uses crystal filters designed using software D. A computer model which can simulate performance of a radio to aid in the design process

A. A radio in which most major signal processing functions are performed by software