FCC Grol element 3 Test Questions And
Answers Verified 100% Correct
Given a power supply with a no load voltage of 12 volts and a full load voltage of 10
volts, what is the percentage of voltage regulation?
A. 17%
B. 80%
C. 20%
D. 83% - ANSWER- C. 20%
What turns ratio does a transformer need in order to match a source impedance of 500
ohms to a load of 10 ohms?
A. 7.1 to 1
B. 14.2 to 1
C. 50 to 1
D. None of these - ANSWER- A. 7.1 to 1
What is the description of an optocoupler?
A. A resistor and a capacitor
B. Two light sources modulated onto a mirrored surface
C. An LED and a photosensitive device
D. An amplitude modulated beam encoder - ANSWER- C. An LED and a photosensitive
device
In Figure 3C4, if a small variable capacitor were installed in place of the dashed line, it
would?
A. Increase gain
B. Increase parasitic oscillations
C. Decrease parasitic oscillations
D. Decrease crosstalk - ANSWER- C. Decrease parasitic oscillations
What is the purpose of a coupling capacitor?
A. It blocks direct current and passes alternating current B.
It blocks alternating current and passes direct current.
C. It increases the resonant frequency of the circuit.
,D. It decreases the resonant frequency of the circuit - ANSWER- A. It blocks direct
current and passes alternating current
A power transformer has a primary winding of 200 turns of #24 wire and a secondary
winding consisting of 500 turns of the same size wire. When 20 volts are applied to the
primary winding, the expected secondary voltage will be:
A. 500 volts.
B. 25 volts.
C. 10 volts
D. 50 volts. - ANSWER- D. 50 volts.
A switching electronic voltage regulator:
A. Varies the conduction of a control element in direct proportion to the line voltage or
load current
B. Provides more than one output voltage
C. Switches the control device on or off, with the duty cycle proportional to t he line or
load conditions
D. Gives a ramp voltage at its output. - ANSWER- C. Switches the control device on or
off, with the duty cycle proportional to the line or load conditions.
A three-terminal regulator:
A. Supplies three voltages with variable current
B. Supplies three voltages at a constant current
C. Contains a voltage reference, error amplifier, sensing resistors and transistors, and a
pass element.
D. Contains three error amplifiers and sensing transistors. - ANSWER- C. Contains a
voltage reference, error amplifier, sensing resistors and transistors, and a pass
element.
How might two similar SCRs be connected to safely distribute the power load of a
circuit?
A. In series
B. In parallel, same polarity
C. In parallel, reverse polarity
D. In a combination series and parallel configuration
3-23C2 What are the three terminals of an SCR? - ANSWER- C. In parallel, reverse
polarity
What are the three terminals of an SCR?
,A. Anode, cathode, and gate.
B. Gate, source, and sink.
C. Base, collector, and emitter.
D. Gate, base 1, and base 2. - ANSWER- A. Anode, cathode, and gate.
What circuit might contain a SCR?
A. Filament circuit of a tube radio receiver
B. A light-dimming circuit
C. Shunt across a transformer primary
D. Bypass capacitor circuit to ground. - ANSWER- B. A light-dimming circuit
What special type of diode is capable of both amplification and oscillation'?
A. Zener diodes.
B. Point contact diodes.
C. Tunnel diodes
D. Junction diodes. - ANSWER- C. Tunnel diodes
What is the principal characteristic of a tunnel diode?
A. High forward resistance.
B. Very high PIV(peak inverse voltage)
C. Negative resistance region
D. High forward current rating. - ANSWER- C. Negative resistance region
What are the elements of a unijunction transistor?
A. Base 1, base 2, and emitter.
B. Gate, cathode, and anode
C. Gate, base 1, and base 2
D. Gate, source, and sink. - ANSWER- A. Base 1, base 2, and emitter.
What does it mean for a transistor to be fully saturated?
A. The collector current is at its maximum value.
B. The collector current is at its minimum value.
C. The transistor's Alpha is at its maximum value.
D. The transistor's Beta is at its maximum value. - ANSWER- A. The collector current is
at its maximum value.
What does it mean for a transistor to be cut off?
, A. There is no base current.
B. The transistor is at its Class A operating point.
C. There is no current between emitter and collector.
D. There is maximum current between emitter and collector. - ANSWER- C. There is no
current between emitter and collector.
For current to flow in an NPN silicon transistor's emitter-collector junction, the base must
be:
A. At least 0.4 volts positive with respect to the emitter.
B. At a negative voltage with respect to the emitter.
C. At least 0.7 volts positive with respect to the emitter.
D. At least 0.7 volts negative with respect to the emitter. - ANSWER- C. At least 0.7
volts positive with respect to the emitter.
An LED facing a photodiode in a light-tight enclosure is commonly known as a/an:
A. Optoisolator
B. Seven segment LED
C. Optointerrupter
D. Infra-red (IR) detector. - ANSWER- A. Optoisolator
What circuit component must be connected in series to protect an LED?
A. Bypass capacitor to ground.
B. Electrolytic capacitor
C. Series resistor
D. Shunt coil in series. - ANSWER- C. Series resistor
What describes a diode junction that is forward biased? A.
It is a high impedance.
B. It conducts very little current
C. It is a low impedance.
D. It is an open circuit. - ANSWER- C. It is a low impedance.
What is the piezoelectric effect?
A. Mechanical vibration of a crystal by the application of a voltage.
B. Mechanical deformation of a crystal by the application of a magnetic field
C.The generation of electrical energy by the application of light.
D. Reversed conduction states when a P-N junction is exposed to light. - ANSWER- A.
Mechanical vibration of a crystal by the application of a voltage
What is the characteristic of the current flow in a series R-L-C circuit at resonance?
Answers Verified 100% Correct
Given a power supply with a no load voltage of 12 volts and a full load voltage of 10
volts, what is the percentage of voltage regulation?
A. 17%
B. 80%
C. 20%
D. 83% - ANSWER- C. 20%
What turns ratio does a transformer need in order to match a source impedance of 500
ohms to a load of 10 ohms?
A. 7.1 to 1
B. 14.2 to 1
C. 50 to 1
D. None of these - ANSWER- A. 7.1 to 1
What is the description of an optocoupler?
A. A resistor and a capacitor
B. Two light sources modulated onto a mirrored surface
C. An LED and a photosensitive device
D. An amplitude modulated beam encoder - ANSWER- C. An LED and a photosensitive
device
In Figure 3C4, if a small variable capacitor were installed in place of the dashed line, it
would?
A. Increase gain
B. Increase parasitic oscillations
C. Decrease parasitic oscillations
D. Decrease crosstalk - ANSWER- C. Decrease parasitic oscillations
What is the purpose of a coupling capacitor?
A. It blocks direct current and passes alternating current B.
It blocks alternating current and passes direct current.
C. It increases the resonant frequency of the circuit.
,D. It decreases the resonant frequency of the circuit - ANSWER- A. It blocks direct
current and passes alternating current
A power transformer has a primary winding of 200 turns of #24 wire and a secondary
winding consisting of 500 turns of the same size wire. When 20 volts are applied to the
primary winding, the expected secondary voltage will be:
A. 500 volts.
B. 25 volts.
C. 10 volts
D. 50 volts. - ANSWER- D. 50 volts.
A switching electronic voltage regulator:
A. Varies the conduction of a control element in direct proportion to the line voltage or
load current
B. Provides more than one output voltage
C. Switches the control device on or off, with the duty cycle proportional to t he line or
load conditions
D. Gives a ramp voltage at its output. - ANSWER- C. Switches the control device on or
off, with the duty cycle proportional to the line or load conditions.
A three-terminal regulator:
A. Supplies three voltages with variable current
B. Supplies three voltages at a constant current
C. Contains a voltage reference, error amplifier, sensing resistors and transistors, and a
pass element.
D. Contains three error amplifiers and sensing transistors. - ANSWER- C. Contains a
voltage reference, error amplifier, sensing resistors and transistors, and a pass
element.
How might two similar SCRs be connected to safely distribute the power load of a
circuit?
A. In series
B. In parallel, same polarity
C. In parallel, reverse polarity
D. In a combination series and parallel configuration
3-23C2 What are the three terminals of an SCR? - ANSWER- C. In parallel, reverse
polarity
What are the three terminals of an SCR?
,A. Anode, cathode, and gate.
B. Gate, source, and sink.
C. Base, collector, and emitter.
D. Gate, base 1, and base 2. - ANSWER- A. Anode, cathode, and gate.
What circuit might contain a SCR?
A. Filament circuit of a tube radio receiver
B. A light-dimming circuit
C. Shunt across a transformer primary
D. Bypass capacitor circuit to ground. - ANSWER- B. A light-dimming circuit
What special type of diode is capable of both amplification and oscillation'?
A. Zener diodes.
B. Point contact diodes.
C. Tunnel diodes
D. Junction diodes. - ANSWER- C. Tunnel diodes
What is the principal characteristic of a tunnel diode?
A. High forward resistance.
B. Very high PIV(peak inverse voltage)
C. Negative resistance region
D. High forward current rating. - ANSWER- C. Negative resistance region
What are the elements of a unijunction transistor?
A. Base 1, base 2, and emitter.
B. Gate, cathode, and anode
C. Gate, base 1, and base 2
D. Gate, source, and sink. - ANSWER- A. Base 1, base 2, and emitter.
What does it mean for a transistor to be fully saturated?
A. The collector current is at its maximum value.
B. The collector current is at its minimum value.
C. The transistor's Alpha is at its maximum value.
D. The transistor's Beta is at its maximum value. - ANSWER- A. The collector current is
at its maximum value.
What does it mean for a transistor to be cut off?
, A. There is no base current.
B. The transistor is at its Class A operating point.
C. There is no current between emitter and collector.
D. There is maximum current between emitter and collector. - ANSWER- C. There is no
current between emitter and collector.
For current to flow in an NPN silicon transistor's emitter-collector junction, the base must
be:
A. At least 0.4 volts positive with respect to the emitter.
B. At a negative voltage with respect to the emitter.
C. At least 0.7 volts positive with respect to the emitter.
D. At least 0.7 volts negative with respect to the emitter. - ANSWER- C. At least 0.7
volts positive with respect to the emitter.
An LED facing a photodiode in a light-tight enclosure is commonly known as a/an:
A. Optoisolator
B. Seven segment LED
C. Optointerrupter
D. Infra-red (IR) detector. - ANSWER- A. Optoisolator
What circuit component must be connected in series to protect an LED?
A. Bypass capacitor to ground.
B. Electrolytic capacitor
C. Series resistor
D. Shunt coil in series. - ANSWER- C. Series resistor
What describes a diode junction that is forward biased? A.
It is a high impedance.
B. It conducts very little current
C. It is a low impedance.
D. It is an open circuit. - ANSWER- C. It is a low impedance.
What is the piezoelectric effect?
A. Mechanical vibration of a crystal by the application of a voltage.
B. Mechanical deformation of a crystal by the application of a magnetic field
C.The generation of electrical energy by the application of light.
D. Reversed conduction states when a P-N junction is exposed to light. - ANSWER- A.
Mechanical vibration of a crystal by the application of a voltage
What is the characteristic of the current flow in a series R-L-C circuit at resonance?
