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Any electrical or electronic device that keeps the voltage of a power source within acceptable limits is known as a voltage regulator. The voltage regulator is required to maintain voltages within the acceptable range for electrical equipment that uses that voltage. This sort of gadget is commonly employed in all types of motor vehicles to adjust the generator’s output voltage to the electrical load and the battery’s charging needs. Voltage regulators are also employed in electronic devices where excessive voltage changes might be harmful.
1. Which of the following are three-pin voltage regulator integrated circuits?
a. Voltage regulators that are fixed
b. Voltage regulators that can be adjusted
c. Both a and b are true.
d. None of the above
d. None of the above
ANSWER- a, b
2. Because a series pass transistor is operating in the active zone of a linear voltage regulator, __________
a. The ripple contents in o/p voltage waveform is very low
b. Then there is no necessity of using high speed transistor
c. Both a and b
d. None of the above
ANSWER- a and b
3. In order to produce the required load current, which kind of IC voltage regulator displays constant fluctuation in transistor impedance?
a. The ripple contents in o/p voltage waveform is very low
b. Then there is no necessity of using high speed transistor
c. Both a and b
d. None of the above
ANSWER- Both a and b
4. In order to give power to an internal circuit, what is the minimum voltage necessary between the input and output of an LM317 voltage regulator?
a. 1V
b. 3V
c. 5V
d. 10V
ANSWER- b
5. The protection diodes in the LM317 voltage regulator prevent the filter capacitors from discharging beyond ______current points.
a. High
b. Low
c. Both a and b
d. None of the above
ANSWER- b
6. The series pass transistor in a linear IC voltage regulator is always in the _____ zone.
a. Active
b. Saturation
c. Cut-off
d. All of the above
ANSWER- a, else it won’t work
7. Switching regulators are series type regulators with a power dissipation of _____ and an efficiency of .
a. increased, increased
b. increased, reduced
c. reduced, increased
d. reduced, reduced
ANSWER- c
8. A power supply’s percent load regulation should be ideally _______ and realistically .
a. zero, small
b. small, zero
c. zero, large
d. large, zero
ANSWER- a
9.At a fixed load current, which regulator performance measure is defined as the change in regulated load voltage owing to changes in line voltage in a particular range?
a. Load balancing
b. Regulation of lines
c. Thermodynamic stability factor
d. Rejection of ripples
ANSWER- b
10. Which of the following things has an impact on a regulated power supply’s output voltage?
a. Make a current load
b. Voltage input
c. Temperature
d. All of the above ones
ANSWER- d
11. Simple current limiting produces too much heat in the
A Zener diode
B Load resistor
C Pass transistor
D Ambient air
ANSWER- b, as the resistor is a bad conductor the currents it stops produces heat.
12.Normally, voltage regulators are used.
A Negative feedback
B Positive feedback
C No feedback
D Phase limiting
ANSWER- a
13. The power dissipation of the pass transistor during regulation is equal to the collector-emitter voltage multiplied by the.
A Base current
B Load current
C Zener current
D Foldback current
ANSWER- b
14. A shorted load will very certainly fail if current limiting is not used.
A Produce zero load current
B Destroy diodes and transistors
C Have a load voltage equal to the zener voltage
D Have too little load current
ANSWER- c
15.In most cases, a current-sensing resistor is used.
A Zero
B Small
C Large
D Open
ANSWER- b
16.The load voltage approaches 0 and the load current approaches zero when foldback current limiting is used.
A A small value
B Infinity
C The zener current
D A destructive level
ANSWER- a
17. A discrete voltage regulator may need a capacitor to avoid.
A Negative feedback
B Excessive load current
C Oscillations
D Current sensing
ANSWER- c
18.The load regulation is when the output of a voltage regulator changes between 15 and 14.7 V between the minimum and highest load current.
A 0
B 1%
C 2%
D 5%
ANSWER- c,Load regulation = 100 x (Voltage(full-minimum) divided by voltage full load.
19. When the line voltage fluctuates across its defined range, the source regulation of a voltage regulator varies from 20 to 19.8 V.
A 0
B 1%
C 2%
D 5%
ANSWER- b,Load regulation = 100 x (Voltage(full-minimum) divided by voltage full load.
20.A voltage regulator’s output impedance is.
A Very small
B Very large
C Equal to the load voltage divided by the load current
D Equal to the input voltage divided by the output current
ANSWER- a
21. Compared to the ripple in a regulator, the ripple out of regulator is
A Equal in value
B Much larger
C Much smaller
D Impossible to determine
ANSWER- c
22. A regulator has a rejection of -60 dB. If the ripple is 1 V, the ripple is
A -60 mV
B 1 mV
C 10 mV
D 1000 V
ANSWER- b
23. Thermal shutdown happens in a regulator ICtypes-
A Power dissipation is too high
B Internal temperature is too high
C Current through the device is too high
D All the above occur
ANSWER- b
24. You may experience oscillations within a linear three-terminal IC regulator if it is more than a few inches from the filter capacitor unless you utilize a filter capacitor.
A Current limiting
B A bypass capacitor on the input pin
C A coupling capacitor on the output pin
D A regulated input voltage
ANSWER- b
25. The output voltage of the 78XX series of voltage regulators is
A Positive
B Negative
C Either positive or negative
D Unregulated
ANSWER- a
26. The 78XX-12 creates regulated voltage of
A 3 V
B 4 V
C 12 V
D 40 V
ANSWER- c
27. The voltage between the base-emitter terminals of a current booster may be used to switch it on.
A A load resistor
B A zener impedance
C Another transistor
D A current-sensing resistor
ANSWER- d
28. A phase splitter generates two output voltages that are equal in magnitude.
A Equal in phase
B Unequal in amplitude
C Opposite in phase
D Very small
ANSWER- c
