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Free download in PDF Basic Electronics Multiple Choice Questions(MCQs) and Answers. These short objective type questions with answers are very important for competitive exams like IIT, JEE, NEET, AIIMS, JIPMER etc.
(1)
A Triac has three terminals viz ………………
[A]
Drain, source, gate
[B]
Two main terminal and a gate terminal
[C]
Cathode, anode, gate
[D]
None of the above
Answer: Two main terminal and a gate terminal
(2)
A diac has ………….. terminals
[A]
Two
[B]
Three
[C]
Four
[D]
None of the above
(3)
Power electronics essentially deals with control of a.c. power at …………
[A]
Frequencies above 20 kHz
[B]
Frequencies above 1000 kHz
[C]
Frequencies less than 10 Hz
[D]
50 Hz frequency
(4)
To turn on UJT, the forward bias on the emitter diode should be …………… the peak point voltage
[A]
Less than
[B]
Equal to
[C]
More than
[D]
None of the above
(5)
A diac is simply ………………
[A]
A single junction device
[B]
A three junction device
[C]
A triac without gate terminal
[D]
None of the above
Answer: A triac without gate terminal
(6)
The current out of an ideal current source is
[A]
Zero
[B]
Constant
[C]
Load resistance dependent
[D]
Internal resistance dependent
(7)
In a constant voltage DC circuit, when the resistance increases, the current will
[A]
Decrease
[B]
Stop
[C]
Increase
[D]
Remains constant
(8)
The triac is …………….
[A]
Like a bidirectional SCR
[B]
A four-terminal device
[C]
Not a thyristor
[D]
Answers (1) and (2)
Answer: Like a bidirectional SCR
(9)
The UJT may be used as ……………….
[A]
Am amplifier
[B]
A sawtooth generator
[C]
A rectifier
[D]
None of the above
Answer: A sawtooth generator
(10)
The voltage out of an ideal voltage source is
[A]
Zero
[B]
Constant
[C]
Load resistance dependent
[D]
Internal resistance dependent
(11)
The unit of electrical resistance is
[A]
Volt
[B]
Amp
[C]
Ohm
[D]
Coulomb
(12)
After peak point, the UJT operates in the ……………. region
[A]
Cut-off
[B]
Saturation
[C]
Negative resistance
[D]
None of the above
Answer: Negative resistance
(13)
Between the peak point and the valley point of UJT emitter characteristics we have ………….. region
[A]
Saturation
[B]
Negative resistance
[C]
Cut-off
[D]
None of the above
Answer: Negative resistance
(14)
In a UJT, the p-type emitter is ……………. doped
[A]
Lightly
[B]
Heavily
[C]
Moderately
[D]
None of the above
(15)
The device that does not have the gate terminal is ……………….
[A]
Triac
[B]
FET
[C]
SCR
[D]
Diac
(16)
A triac has …………….. semiconductor layers
[A]
Two
[B]
Three
[C]
Four
[D]
Five
(17)
When the emitter terminal of a UJT is open, the resistance between the base terminal is generally ………………..
[A]
High
[B]
Low
[C]
Extremely low
[D]
None of the above
(18)
When the temperature increases, the inter-base resistance (RBB) of a UJT ………….
[A]
Increases
[B]
Decreases
[C]
Remains the same
[D]
None of the above
(19)
A diac is turned on by …………………
[A]
A breakover voltage
[B]
Gate voltage
[C]
Gate current
[D]
None of the above
Answer: A breakover voltage
(20)
Which of the following is not a characteristic of UJT?
[A]
Intrinsic stand off ratio
[B]
Negative resistance
[C]
Peak-point voltage
[D]
Bilateral conduction
Answer: Bilateral conduction
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