Power Electronics MCQs 1

Power Electronics MCQs 1:- In This Article, we have provided some MCQs For Power Electronics Students. Power Electronics MCQs 1 could be quite helpful for those who are preparing for GATE, ESE, or for any interviews you can take a look at it.

1.The peak inverse voltage required for the diode shown in the figure below is

Power Electronics MCQs 1
  • a) 300 V 
  • b) 100 V 
  • c) 200 V 
  • d) 400 V

Ans:- d) 400 V

2. For high frequency applications of over10 kW power rating, …………….. type of diodes are used: 

  • a) Power frequency 
  • b) Schottky 
  • c) fast recovery 
  • d) medium recovery

Ans :- c) fast recovery 

3. An SCR with a latching current of 10 mA is connected to 10V, 50 Hz sinusoidal source feeding an R-L load of 100Ω, 10mH connected in series. If the SCR is fired at ωt= 45°, with a single firing pulse width duration of 7.5 μs, the current in the circuit after the firing instant will be 

  • a) 100 mA 
  • b) 70 mA 
  • c) 0 A 
  • d) None of the above

Ans:- c) 0 A 

4. A conducting thyristor can be turned-off by …………(decreasing/increasing) the anode current ……….. (below/above) the ………….(latching/holding) current and applying a ………….(zero/forward/reverse) voltage across the SCR for a short interval. 

  • a) decreasing, below, holding, reverse 
  • b) decreasing, below, latching,
  • c) reverse increasing, above, latching, zero 
  • d) increasing, above, holding, reverse

Ans:- a) decreasing, below, holding, reverse 

5. A single phase ac voltage source of peak magnitude Vm volts and source frequency of ω rad/s, feeds a resistive load through a full-wave rectifier circuit. The average output voltage, V0 (in volts) of the rectifier circuit with diodes having reverse recovery time of trr seconds is given by, 

  • a) V0 =2Vm/π 
  • b) zero 
  • c) V0 =(2Vm/π) (1+cosωtrr
  • d) V0 =(Vm/π) (1+cosωtrr)

Ans :- d) V0 =(Vm/π) (1+cosωtrr)

6. The ON state resistances of two power diodes connected in parallel to share a load of 1 kA are 0.55 and 0.65 mΩ respectively. The value of series resistance (in mΩ) to be connected with each of them to ensure equal current sharing with a tolerance of 10% is 

  • a) 0.1 
  • b) 0.4 
  • c) 0.675 
  • d) 0.735

Ans:- b) 0.4 

7. An SCR circuit has the following rating: VLine=220V rms., f=50Hz load resistance, Rl=60 Ω, dv/dt=70 V/μs and di/dt = 60A/μs. The value of snubbing capacitor (in pF) and snubbing inductance (in μH) needed are ……………, and …………….. respectively. 

  • a) 86.42, and 4.44 
  • b) 74.08, and 5.18 
  • c) 52.38, and 3.66 
  • d) 0.074, and 5.18

Ans:- b) 74.08, and 5.18 


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