Discussion
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- Question
In a single phase full wave regulator feeding an R-L load, the power factor angle of load is ?. The range of control of firing angle a is
Options- A. 0 ? a ? p
- B. ? ? a ? p
- C. 0 ? a ? (p - ?)
- D. ? ? a ? (p + ?)
- Correct Answer
- ? ? a ? p
- 1. McMurray Bedford full bridge inverter uses
Options- A. natural commutation
- B. auxiliary commutation
- C. complementary commutation
- D. any of the above Discuss
- 2. In a stud mounted SCR, the stud is
Options- A. in thermal contact with heat sink
- B. insulated from heat sink
- C. in electrical and thermal contact with heat sink
- D. in either electrical or thermal contact with heat sink Discuss
- 3. Assertion (A): A GTO circuit is more compact than SCR circuit
Reason (R): A GTO can be turned off by negative gate pulse.
Options- A. Both A and R are correct and R is correct explanation of A
- B. Both A and R correct but R is not correct explanation of A
- C. A is correct but R is wrong
- D. A is wrong but R is correct Discuss
- 4. A single phase half wave converter is used to charge a battery of 50 V. The thyristor is continuously fired by dc signal. Input voltage is v = Vm sin ?t. The thyristor will conduct
Options- A. from 0 to 180°
- B. when v > 50 V
- C. from 0 to 90°
- D. When v < 50 V Discuss
- 5. In a 3 phase semiconverter, the dc output voltage for a certain firing angle is 50% of the maximum possible value. The firing angle is
Options- A. 30°
- B. 60°
- C. 90°
- D. 120° Discuss
- 6. If a step down chopper is fed by a dc voltage V with Ton and Toff are on and off periods then
is
Options- A. average output voltage
- B. rms output voltage
- C. average or rms output voltage depending on load
- D. neither of the above Discuss
- 7. In a thyristor the gate lead is connected to the n layer near the p layer to which anode is connected.
Options- A. True
- B. False Discuss
- 8. The characteristics of which device has peak point and valley point
Options- A. SCR
- B. PUT
- C. SCS
- D. Shockley diode Discuss
- 9. The two-transistor model of a thyristor consists of two transistors :
Options- A. one n-p-n and other p-n-p
- B. both p-n-p
- C. both n-p-n
- D. one n-p-n and other UJT Discuss
- 10. Which of these commutation methods uses an external pulse for commutation?
Options- A. Class A
- B. Class C
- C. Class E
- D. Class F Discuss
Power Electronics problems
Search Results
Correct Answer: complementary commutation
Correct Answer: in electrical and thermal contact with heat sink
Correct Answer: Both A and R are correct and R is correct explanation of A
Explanation:
Since commutation circuit is not required, GTO circuit is compact.
Correct Answer: when v > 50 V
Explanation:
Thyristor can conduct only when it is forward biased. This occurs only when v > 50 V.
Correct Answer: 90°
Explanation:
Vdc ? (1 + cos a). Maximum possible output voltage occurs when a = 0.
Correct Answer: average output voltage
Correct Answer: False
Correct Answer: PUT
Correct Answer: one n-p-n and other p-n-p
Correct Answer: Class E
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