General Class License Exam Questions

Subelement G7

Practical Circuits

Groups

G7A - Power supplies; and schematic symbols
G7B - Digital circuits; amplifiers and oscillators
G7C - Receivers and transmitters; filters, oscillators

Question Display Options:

Default

Hide Answers

Hide Incorrect Answers

Highlight Correct Answers

Group G7A Power supplies; and schematic symbols

G7A01 What useful feature does a power supply bleeder resistor provide?

It acts as a fuse for excess voltage
It ensures that the filter capacitors are discharged when power is removed
It removes shock hazards from the induction coils
It eliminates ground loop current

G7A02 Which of the following components are used in a power supply filter network?

Diodes
Transformers and transducers
Quartz crystals
Capacitors and inductors

G7A03 What is the peak-inverse-voltage across the rectifiers in a full-wave bridge power supply?

One-quarter the normal output voltage of the power supply
Half the normal output voltage of the power supply
Double the normal peak output voltage of the power supply
Equal to the normal peak output voltage of the power supply

G7A04 What is the peak-inverse-voltage across the rectifier in a half-wave power supply?

One-half the normal peak output voltage of the power supply
One-half the normal output voltage of the power supply
Equal to the normal output voltage of the power supply
Two times the normal peak output voltage of the power supply

G7A05 What portion of the AC cycle is converted to DC by a half-wave rectifier?

90 degrees
180 degrees
270 degrees
360 degrees

G7A06 What portion of the AC cycle is converted to DC by a full-wave rectifier?

90 degrees
180 degrees
270 degrees
360 degrees

G7A07 What is the output waveform of an unfiltered full-wave rectifier connected to a resistive load?

A series of DC pulses at twice the frequency of the AC input
A series of DC pulses at the same frequency as the AC input
A sine wave at half the frequency of the AC input
A steady DC voltage

G7A08(C) Which of the following is an advantage of a switchmode power supply as compared to a linear power supply?

Faster switching time makes higher output voltage possible
Fewer circuit components are required
High frequency operation allows the use of smaller components
All of these choices are correct

G7A09 Which symbol in figure G7-1 represents a field effect transistor?

Symbol 2
Symbol 5
Symbol 1
Symbol 4

G7A10 Which symbol in figure G7-1 represents a Zener diode?

Symbol 4
Symbol 1
Symbol 11
Symbol 5

G7A11 Which symbol in figure G7-1 represents an NPN junction transistor?

Symbol 1
Symbol 2
Symbol 7
Symbol 11

G7A12 Which symbol in Figure G7-1 represents a multiple-winding transformer?

Symbol 4
Symbol 7
Symbol 6
Symbol 1

G7A13 Which symbol in Figure G7-1 represents a tapped inductor?

Symbol 7
Symbol 11
Symbol 6
Symbol 1

Group G7B Digital circuits; amplifiers and oscillators

G7B01 Complex digital circuitry can often be replaced by what type of integrated circuit?

Microcontroller
Charge-coupled device
Phase detector
Window comparator

G7B02 Which of the following is an advantage of using the binary system when processing digital signals?

Binary "ones" and "zeros" are easy to represent by an "on" or "off" state
The binary number system is most accurate
Binary numbers are more compatible with analog circuitry
All of these choices are correct

G7B03 Which of the following describes the function of a two input AND gate?

Output is high when either or both inputs are low
Output is high only when both inputs are high
Output is low when either or both inputs are high
Output is low only when both inputs are high

G7B04 Which of the following describes the function of a two input NOR gate?

Output is high when either or both inputs are low
Output is high only when both inputs are high
Output is low when either or both inputs are high
Output is low only when both inputs are high

G7B05 How many states does a 3-bit binary counter have?

G7B06 What is a shift register?

A clocked array of circuits that passes data in steps along the array
An array of operational amplifiers used for tri-state arithmetic operations
A digital mixer
An analog mixer

G7B07 What are the basic components of virtually all sine wave oscillators?

An amplifier and a divider
A frequency multiplier and a mixer
A circulator and a filter operating in a feed-forward loop
A filter and an amplifier operating in a feedback loop

G7B08 How is the efficiency of an RF power amplifier determined?

Divide the DC input power by the DC output power
Divide the RF output power by the DC input power
Multiply the RF input power by the reciprocal of the RF output power
Add the RF input power to the DC output power

G7B09 What determines the frequency of an LC oscillator?

The number of stages in the counter
The number of stages in the divider
The inductance and capacitance in the tank circuit
The time delay of the lag circuit

G7B10 Which of the following is a characteristic of a Class A amplifier?

Low standby power
High Efficiency
No need for bias
Low distortion

G7B11 For which of the following modes is a Class C power stage appropriate for amplifying a modulated signal?

SSB
CW
AM
All of these choices are correct

G7B12 Which of these classes of amplifiers has the highest efficiency?

Class A
Class B
Class AB
Class C

G7B13 What is the reason for neutralizing the final amplifier stage of a transmitter?

To limit the modulation index
To eliminate self-oscillations
To cut off the final amplifier during standby periods
To keep the carrier on frequency

G7B14 Which of the following describes a linear amplifier?

Any RF power amplifier used in conjunction with an amateur transceiver
An amplifier in which the output preserves the input waveform
A Class C high efficiency amplifier
An amplifier used as a frequency multiplier

Group 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?

Carrier oscillator
Filter
IF amplifier
RF amplifier

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?

Discriminator
Detector
IF amplifier
Balanced modulator

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?

Balanced modulator
IF amplifier
Mixer
Detector

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?

RF oscillator
IF filter
Balanced modulator
Product detector

G7C05 Which of the following is an advantage of a transceiver controlled by a direct digital synthesizer (DDS)?

Wide tuning range and no need for band switching
Relatively high power output
Relatively low power consumption
Variable frequency with the stability of a crystal oscillator

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?

Substantially higher
About the same
Substantially lower
Twice the transmission line impedance

G7C07 What is the simplest combination of stages that implement a superheterodyne receiver?

RF amplifier, detector, audio amplifier
RF amplifier, mixer, IF discriminator
HF oscillator, mixer, detector
HF oscillator, prescaler, audio amplifier

G7C08 What type of circuit is used in many FM receivers to convert signals coming from the IF amplifier to audio?

Product detector
Phase inverter
Mixer
Discriminator

G7C09 Which of the following is needed for a Digital Signal Processor IF filter?

An analog to digital converter
A digital to analog converter
A digital processor chip
All of the these choices are correct

G7C10 How is Digital Signal Processor filtering accomplished?

By using direct signal phasing
By converting the signal from analog to digital and using digital processing
By differential spurious phasing
By converting the signal from digital to analog and taking the difference of mixing products

G7C11 What is meant by the term "software defined radio" (SDR)?

A radio in which most major signal processing functions are performed by software
A radio that provides computer interface for automatic logging of band and frequency
A radio that uses crystal filters designed using software
A computer model that can simulate performance of a radio to aid in the design process