1. Chopper is also known as
(A) AC transfromer.
(B) DC transformer.
(C) voltage changer.
(D) voltage reducer.
Answer ⇓
2. A thyristor can be termed as
(A) AC switch.
(B) DC switch.
(C) both AC and DC switch.
(D) square wave switch.
Answer ⇓
3. Which of the following semiconductor power device is not a current triggered device
(A) SCR.
(B) GTO.
(C) TRIAC.
(D) MOSFET.
Answer ⇓
4. IGBT is a modern power semiconductor device, that combine the characteristics of
(A) BJT and SCR.
(B) SCR and MOSFET.
(C) MOSFET and BJT.
(D) GTO and Thyristor.
Answer ⇓
5. Which of the following power electronic device can be used for high frequency switching application?
(A) BJT.
(B) Power MOSFET.
(C) Schottky diode.
(D) Microwave transistor.
Answer ⇓
6. In a 3 phase fully controlled converter the firing frequency is
(A) 3 times the line frequency.
(B) 6 times the line frequency.
(C) 9 times the line frequency.
(D) 12 times the line frequency.
Answer ⇓
7. Thyristor can be protected from over voltages by using
(A) voltage clamping device.
(B) fuse.
(C) heat sink.
(D) snubber circuit.
Answer ⇓
8. Turn on and turn off times of transistor depends on
(A) applied voltage.
(B) current gain.
(C) junction capacitance.
(D) applied frequency.
Answer ⇓
9. A thyristor controlled reactor is used to get
(A) variable resistance.
(B) variable capacitance.
(C) variable inductance.
(D) improved reactive power factor.
Answer ⇓
10. A semiconductor device which act like a diode and two transistors is
(A) TRIAC.
(B) DIAC.
(C) UJT.
(D) MOSFET.
Answer ⇓
11. UJT is known as
(A) voltage controlled device.
(B) current controlled device.
(C) relaxation oscillator.
(D) triggered device.
Answer ⇓
12. A thyristor can termed as
(A) ac switches.
(B) dc switches.
(C) both ac and dc switches.
(D) square wave switches.
Answer ⇓
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