UJT MCQS Unijunction transistor questions



1.What are the working regions of a unijunction transistor?

  • a) Linear region
  • b) Negative Resistance region
  • c) Saturation region
  • d) Cut-off region

2.How many terminals are there in a unijunction transistor?

  • a) 1
  • b) 2
  • c) 3
  • d) 4

3.What are unijunction transistors used for?

  • a) Amplifying a circuit
  • b) Circuit breaker
  • c) Splitting device
  • d) On-Off switching device

4.What are the terminals of a unijunction transistor?

  • a) Collector, Base and Emitter
  • b) Emitter, Base 1 and Base 2
  • c) Gate, Drain and Source
  • d) Gate, Drain, Body and Source

5.Which type of material is the channel of a unijunction transistor made up of?

  • a) PN type
  • b) It doesn’t affect the working
  • c) P type
  • d) N type

6.Unijunction transistors have unidirectional conductivity and positive impedance characteristics.

  • a) True
  • b) False

7.What is the generalized value for the voltage across resistor RB1 in a unijunction transistor?

  • a) VRB1 = (RB2 / RB1 + RB2) × VBB
  • b) VRB1 = (RB2 / RB1 – RB2) × VBB
  • c) VRB1 = (RB1 / RB1 + RB2) × VBB
  • d) VRB1 = (RB1 / RB1 – RB2) × VBB


8.A UJT has ___________.

  • a) Two pn junctions
  • b) One pn junction
  • c) Three pn junctions
  • d) None of the above

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9.The UJT may be used as ___________.

  • a) An amplifier
  • b) A sawtooth generator
  • c) A rectifier
  • d) None of the above

10.In a UJT, the p-type emitter is ……………. doped

  • Lightly
  • Heavily
  • Moderately
  • None of the above

11.When the emitter terminal of a UJT is open, the resistance between the base terminal is generally ………………..

  • High
  • Low
  • Extremely low
  • None of the above

12.When a UJT is turned ON, the resistance between emitter terminal and lower base terminal …………….

  • Remains the same
  • Is decreased
  • Is increased
  • None of the above

13.To turn on UJT, the forward bias on the emitter diode should be …………… the peak point voltage

  • Less than
  • Equal to
  • More than
  • None of the above

14.A UJT is sometimes called …………. diode

  • Low resistance
  • High resistance
  • Single-base
  • Double-base

 15.When the temperature increases, the inter-base resistance (RBB) of a UJT ………….

  • Increases
  • Decreases
  • Remains the same
  • None of the above

16.Between the peak point and the valley point of UJT emitter characteristics we have ………….. region

  • Saturation
  • Negative resistance
  • Cut-off
  • None of the above

17.After peak point, the UJT operates in the ……………. region

  • Cut-off
  • Saturation
  • Negative resistance
  • None of the above

18.Which of the following is not a characteristic of UJT?

  • Intrinsic stand off ratio
  • Negative resistance
  • Peak-point voltage
  • Bilateral conduction
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