## General Class Exam Question Pool- Subelement G-7

###### Subelement G-6           Subelement G-7          Subelement G-8          Subbelement G-9          Subelement G-0

G7 – PRACTICAL CIRCUITS [3 Exam Questions – 3 Groups]

G7A Power supplies; and schematic symbols

G7A01

What useful feature does a power supply bleeder resistor provide?

A. It acts as a fuse for excess voltage

B. It ensures that the filter capacitors are discharged when power is removed

C. It removes shock hazards from the induction coils

D. It eliminates ground loop current

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G7A02

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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G7A03

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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G7A04

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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G7A05

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

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G7A06

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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G7A07

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

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G7A08

Which of the following is an advantage of a switchmode 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

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G7A09

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

A. Symbol 2

B. Symbol 5

C. Symbol 1

D. Symbol 4

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G7A10

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

A. Symbol 4

B. Symbol 1

C. Symbol 11

D. Symbol 5

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G7A11

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

A. Symbol 1

B. Symbol 2

C. Symbol 7

D. Symbol 11

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G7A12

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

A. Symbol 4

B. Symbol 7

C. Symbol 6

D. Symbol 1

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G7A13

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

A. Symbol 7

B. Symbol 11

C. Symbol 6

D. Symbol 1

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G7B - Digital circuits; amplifiers and oscillators

G7B01

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

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G7B02

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 by 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

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G7B03

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

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G7B04

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

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G7B05

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

A. 3

B. 6

C. 8

D. 16

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G7B06

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

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G7B07

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

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G7B08

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

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G7B09

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

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G7B10

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

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G7B11

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

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G7B12

Which of these classes of amplifiers has the highest efficiency?

A. Class A

B. Class B

C. Class AB

D. Class C

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G7B13

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

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G7B14

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

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G7C - Receivers and transmitters; filters, oscillators

G7C01

Which of the following is used to process signals from the balanced modulator then send them to the mixer in some single sideband phone transmitters?

A. Carrier oscillator

B. Filter

C. IF amplifier

D. RF amplifier

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G7C02

Which circuit is used to combine signals from the carrier oscillator and speech amplifier then send the result to the filter in some single sideband phone transmitters?

A. Discriminator

B. Detector

C. IF amplifier

D. Balanced modulator

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G7C03

What circuit is used to process signals from the RF amplifier and local oscillator then send the result to the IF filter in a superheterodyne receiver?

A. Balanced modulator

B. IF amplifier

C. Mixer

D. Detector

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G7C04

What circuit is used to combine signals from the IF amplifier and BFO and send the result to the AF amplifier in some single sideband receivers?

A. RF oscillator

B. IF filter

C. Balanced modulator

D. Product detector

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G7C05

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

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G7C06

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

C. Substantially lower

D. Twice the transmission line impedance

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G7C07

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, prescaler, audio amplifier

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G7C08

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

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G7C09

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

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G7C10

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

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G7C11

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 that provides computer interface for automatic logging of band and frequency

C. A radio that uses crystal filters designed using software

D. A computer model that can simulate performance of a radio to aid in the design process

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