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**

- 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 V _{m} volts and source frequency of ω rad/s, feeds a resistive load through a full-wave rectifier circuit. The average output voltage, V_{0} (in volts) of the rectifier circuit with diodes having reverse recovery time of t_{rr} seconds is given by, **

- a) V
_{0}=2V_{m}/π - b) zero
- c) V
_{0}=(2V_{m}/π) (1+cosωt_{rr}) - d) V
_{0}=(V_{m}/π) (1+cosωt_{rr})

**Ans :- d) V _{0} =(V_{m}/π) (1+cosωt_{rr}) **

**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: V _{Line}=220V rms., f=50Hz load resistance, R_{l}=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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