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Extra Class Exam Question Pool

effective 7/01/2016 thru 6/29/2020

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2016-E7D: Power supplies and voltage regulators; Solar array charge controllers

2016-E7D01: What is one characteristic of a linear electronic voltage regulator?

The conduction of a control element is varied to maintain a constant output voltage

It has a ramp voltage as its output

It eliminates the need for a pass transistor

The control element duty cycle is proportional to the line or load conditions

2016-E7D02: What is one characteristic of a switching electronic voltage regulator?

The controlled device's duty cycle is changed to produce a constant average output voltage

The resistance of a control element is varied in direct proportion to the line voltage or load current

It is generally less efficient than a linear regulator

It gives a ramp voltage at its output

2016-E7D03: What device is typically used as a stable reference voltage in a linear voltage regulator?

A Zener diode

A tunnel diode


A varactor diode

2016-E7D04: Which of the following types of linear voltage regulator usually make the most efficient use of the primary power source?

A series regulator

A series current source

A shunt regulator

A shunt current source

2016-E7D05: Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

A shunt regulator

A constant current source

A series regulator

A shunt current source

2016-E7D06: What is the purpose of Q1 in the circuit shown in Figure E7-3?

It increases the current-handling capability of the regulator

It provides negative feedback to improve regulation

It provides a constant load for the voltage source

It provides D1 with current

2016-E7D07: What is the purpose of C2 in the circuit shown in Figure E7-3?

It bypasses hum around D1

It is a brute force filter for the output

To self-resonate at the hum frequency

To provide fixed DC bias for Q1

2016-E7D08: What type of circuit is shown in Figure E7-3?

Linear voltage regulator

Switching voltage regulator

Grounded emitter amplifier

Emitter follower

2016-E7D09: What is the main reason to use a charge controller with a solar power system?

Prevention of battery damage due to overcharge

Prevention of battery undercharge

Control of electrolyte levels during battery discharge

Matching of day and night charge rates

2016-E7D10: What is the primary reason that a high-frequency switching type high voltage power supply can be both less expensive and lighter in weight than a conventional power supply?

The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output

The inverter design does not require any output filtering

It uses a diode bridge rectifier for increased output

It uses a large power factor compensation capacitor to create free power from the unused portion of the AC cycle

2016-E7D11: What circuit element is controlled by a series analog voltage regulator to maintain a constant output voltage?

Pass transistor

Reference voltage

Switching inductance

Error amplifier

2016-E7D12: What is the drop-out voltage of an analog voltage regulator?

Minimum input-to-output voltage required to maintain regulation

Minimum input voltage for rated power dissipation

Maximum amount that the output voltage drops when the input voltage is varied over its specified range

Maximum amount that the output voltage may decrease at rated load

2016-E7D13: What is the equation for calculating power dissipation by a series connected linear voltage regulator?

Voltage difference from input to output multiplied by output current

Input voltage multiplied by input current

Input voltage divided by output current

Output voltage multiplied by output current

2016-E7D14: What is one purpose of a "bleeder" resistor in a conventional unregulated power supply?

To improve output voltage regulation

To cut down on waste heat generated by the power supply

To balance the low-voltage filament windings

To boost the amount of output current

2016-E7D15: What is the purpose of a "step-start" circuit in a high voltage power supply?

To allow the filter capacitors to charge gradually

To provide a dual-voltage output for reduced power applications

To compensate for variations of the incoming line voltage

To allow for remote control of the power supply

2016-E7D16: When several electrolytic filter capacitors are connected in series to increase the operating voltage of a power supply filter circuit, why should resistors be connected across each capacitor?

All of these choices are correct

To equalize, as much as possible, the voltage drop across each capacitor

To provide a safety bleeder to discharge the capacitors when the supply is off

To provide a minimum load current to reduce voltage excursions at light loads

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2016-E7C: Filters and matching networks: types of networks; types of filters; filter applications; filter characteristics; impedance matching; DSP filtering
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2016-E7E: Modulation and demodulation: reactance, phase and balanced modulators; detectors; mixer stages
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