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Amateur Radio 2024 - General > G7 – PRACTICAL CIRCUITS [3 Exam Questions – 3 Groups] 38 Questions > Flashcards

G7 – PRACTICAL CIRCUITS [3 Exam Questions – 3 Groups] 38 Questions Flashcards

1
Q

“What is the function of a power supply bleeder resistor?”

A. It acts as a fuse for excess voltage
B. It discharges the filter capacitors when power is removed
C. It removes shock hazards from the induction coils
D. It eliminates ground loop current

A

B. It discharges the filter capacitors when power is removed

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2
Q

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

A. Diodes
B. Transformers and transducers
C. Capacitors and inductors
D. All these choices are correct

A

C. Capacitors and inductors

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3
Q

“Which type of rectifier circuit uses two diodes and a center-tapped transformer?”

A. Full-wave
B. Full-wave bridge
C. Half-wave
D. Synchronous

A

A. Full-wave

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4
Q

“What is characteristic of a half-wave rectifier in a power supply?”

A. Only one diode is required
B. The ripple frequency is twice that of a full-wave rectifier
C. More current can be drawn from the half-wave rectifier
D. The output voltage is two times the peak input voltage

A

A. Only one diode is required

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5
Q

“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

A

B. 180 degrees

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6
Q

“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

A

D. 360 degrees

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7
Q

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

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8
Q

“Which of the following is characteristic 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. Inherently more stable

A

C. High-frequency operation allows the use of smaller components

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9
Q

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

A. Symbol 2
B. Symbol 5
C. Symbol 1
D. Symbol 4

A

C. Symbol 1

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10
Q

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

A. Symbol 4
B. Symbol 1
C. Symbol 11
D. Symbol 5

A

D. Symbol 5

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11
Q

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

A. Symbol 1
B. Symbol 2
C. Symbol 7
D. Symbol 11

A

B. Symbol 2

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12
Q

“Which symbol in Figure G7-1 represents a solid core transformer?”

A. Symbol 4
B. Symbol 7
C. Symbol 6
D. Symbol 1

A

C. Symbol 6

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13
Q

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

A. Symbol 7
B. Symbol 11
C. Symbol 6
D. Symbol 1

A

A. Symbol 7

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14
Q

“What is the purpose of neutralizing an amplifier?”

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

A

B. To eliminate self-oscillations

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15
Q

“Which of these classes of amplifiers has the highest efficiency?”

A. Class A
B. Class B
C. Class AB
D. Class C

A

D. Class C

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16
Q

“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

A

B. Output is high only when both inputs are high

17
Q

“In a Class A amplifier, what percentage of the time does the amplifying device conduct?”

A. 100%
B. More than 50% but less than 100%
C. 50%
D. Less than 50%

A

A. 100%

18
Q

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

A. 3
B. 6
C. 8
D. 16

A

C. 8

19
Q

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

20
Q

“Which of the following are basic components of a sine wave oscillator?”

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

A

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

21
Q

“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

A

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

22
Q

“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

A

C. The inductance and capacitance in the tank circuit

23
Q

“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

A

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

24
Q

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

A. SSB
B. FM
C. AM
D. All these choices are correct

A

B. FM

25
Q

“What circuit is used to select one of the sidebands from a balanced modulator?”

A. Carrier oscillator
B. Filter
C. IF amplifier
D. RF amplifier

A

B. Filter

26
Q

“What output is produced by a balanced modulator?”

A. Frequency modulated RF
B. Audio with equalized frequency response
C. Audio extracted from the modulation signal
D. Double-sideband modulated RF

A

D. Double-sideband modulated RF

27
Q

“What is one reason to use an impedance matching transformer at a transmitter output?”

A. To minimize transmitter power output
B. To present the desired impedance to the transmitter and feed line
C. To reduce power supply ripple
D. To minimize radiation resistance

A

B. To present the desired impedance to the transmitter and feed line

28
Q

“How is a product detector used?”

A. Used in test gear to detect spurious mixing products
B. Used in transmitter to perform frequency multiplication
C. Used in an FM receiver to filter out unwanted sidebands
D. Used in a single sideband receiver to extract the modulated signal

A

D. Used in a single sideband receiver to extract the modulated signal

29
Q

“Which of the following is characteristic of a direct digital synthesizer (DDS)?”

A. Extremely narrow tuning range
B. Relatively high-power output
C. Pure sine wave output
D. Variable output frequency with the stability of a crystal oscillator

A

D. Variable output frequency with the stability of a crystal oscillator

30
Q

“Which of the following is an advantage of a digital signal processing (DSP) filter compared to an analog filter?”

A. A wide range of filter bandwidths and shapes can be created
B. Fewer digital components are required
C. Mixing products are greatly reduced
D. The DSP filter is much more effective at VHF frequencies

A

A. A wide range of filter bandwidths and shapes can be created

31
Q

“What term specifies a filter’s attenuation inside its passband?”

A. Insertion loss
B. Return loss
C. Q
D. Ultimate rejection

A

A. Insertion loss

32
Q

“Which parameter affects receiver sensitivity?”

A. Input amplifier gain
B. Demodulator stage bandwidth
C. Input amplifier noise figure
D. All these choices are correct

A

D. All these choices are correct

33
Q

“What is the phase difference between the I and Q RF signals that software-defined radio (SDR) equipment uses for modulation and demodulation?”

A. Zero
B. 90 degrees
C. 180 degrees
D. 45 degrees

A

B. 90 degrees

34
Q

“What is an advantage of using I-Q modulation with software-defined radios (SDRs)?”

A. The need for high resolution analog-to-digital converters is eliminated
B. All types of modulation can be created with appropriate processing
C. Minimum detectible signal level is reduced
D. Automatic conversion of the signal from digital to analog

A

B. All types of modulation can be created with appropriate processing

35
Q

“Which of these functions is performed by software in a software-defined radio (SDR)?”

A. Filtering
B. Detection
C. Modulation
D. All these choices are correct

A

D. All these choices are correct

36
Q

“What is the frequency above which a low-pass filter’s output power is less than half the input power?”

A. Notch frequency
B. Neper frequency
C. Cutoff frequency
D. Rolloff frequency

A

C. Cutoff frequency

37
Q

“What term specifies a filter’s maximum ability to reject signals outside its passband?”

A. Notch depth
B. Rolloff
C. Insertion loss
D. Ultimate rejection

A

D. Ultimate rejection

38
Q

“The bandwidth of a band-pass filter is measured between what two frequencies?”

A. Upper and lower half-power
B. Cutoff and rolloff
C. Pole and zero
D. Image and harmonic

A

A. Upper and lower half-power

Amateur Radio 2024 - General (10 decks)

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