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236 matching questions

Question #220Basic Electricity and Electronics

What are the two major ratings that must not be exceeded for silicon-diode rectifiers?

Peak inverse voltage; average forward current ✓ Correct answer
Average power; average voltage
Capacitive reactance; avalanche voltage
Peak load impedance; peak voltage

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Question #221Basic Electricity and Electronics

What is the approximate junction threshold voltage of a germanium diode?

0.1 volt
0.3 volts ✓ Correct answer
0.7 volts
1.0 volts

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Question #222Basic Electricity and Electronics

When two or more diodes are connected in parallel to increase current handling capacity, what is the purpose of the resistor connected in series with each diode?

The resistors ensure the thermal stability of the power supply
The resistors regulate the power supply output voltage
The resistors ensure that one diode doesn't carry most of the current ✓ Correct answer
The resistors act as swamping resistors in the circuit

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Question #223Basic Electricity and Electronics

What is the approximate junction threshold voltage of a silicon diode?

0.1 volt
0.3 volts
0.7 volts ✓ Correct answer
1.0 volts

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Question #224Basic Electricity and Electronics

Which of the following is an advantage of using a Schottky diode in an RF switching circuit as compared to a standard silicon diode?

Lower capacitance ✓ Correct answer
Lower inductance
Longer switching times
Higher breakdown voltage

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Question #225Basic Electricity and Electronics

What are the stable operating points for a bipolar transistor that is used as a switch in a logic circuit?

Its saturation and cut-off regions ✓ Correct answer
Its active region (between the cut-off and saturation regions)
Between its peak and valley current points
Between its enhancement and deletion modes

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Question #226Basic Electricity and Electronics

Why is it often necessary to insulate the case of a large power transistor?

To increase the beta of the transistor
To improve the power dissipation capability
To reduce stray capacitance
To avoid shorting the collector or drain voltage to ground ✓ Correct answer

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Question #231Basic Electricity and Electronics

What is an advantage of the low internal resistance of Nickel Cadmium batteries?

Long life
High discharge current ✓ Correct answer
High voltage
Rapid recharge

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Question #232Basic Electricity and Electronics

What is the minimum allowable discharge voltage for maximum life of a standard 12 volt lead acid battery?

6 volts
8.5 volts
10.5 volts ✓ Correct answer
12 volts

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Question #237Basic Electricity and Electronics

Which of the following causes opposition to the flow of alternating current in an inductor?

Conductance
Reluctance
Admittance
Reactance ✓ Correct answer

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Question #238Basic Electricity and Electronics

Which of the following causes opposition to the flow of alternating current in a capacitor?

Conductance
Reluctance
Reactance ✓ Correct answer
Admittance

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Question #240Basic Electricity and Electronics

How does a capacitor react to AC?

As the frequency of the applied AC increases, the reactance decreases ✓ Correct answer
As the frequency of the applied AC increases, the reactance increases
As the amplitude of the applied AC increases, the reactance increases
As the amplitude of the applied AC increases, the reactance decreases

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Question #245Basic Electricity and Electronics

Why should core saturation of a conventional impedance matching transformer be avoided?

Harmonics and distortion could result ✓ Correct answer
Magnetic flux would increase with frequency
RF susceptance would increase
Temporary changes of the core permeability could result

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Question #246Basic Electricity and Electronics

What is one reason to use an impedance matching transformer?

To reduce power dissipation in the transmitter
To maximize the transfer of power ✓ Correct answer
To minimize SWR at the antenna
To minimize SWR in the transmission line

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Question #248Basic Electricity and Electronics

Which of the following describes one method of impedance matching between two AC circuits?

Insert an LC network between the two circuits ✓ Correct answer
Reduce the power output of the first circuit
Increase the power output of the first circuit
Insert a circulator between the two circuits

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Question #250Basic Electricity and Electronics

How does the total current relate to the individual currents in each branch of a parallel circuit?

It equals the average of each branch current
It decreases as more parallel branches are added to the circuit
It equals the sum of the currents through each branch (Kirchhoff’s Current Law) ✓ Correct answer
It is the sum of the reciprocal of each individual voltage drop

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Question #253Basic Electricity and Electronics