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The efficiency of a full wave rectifier using centre tapped transformer is twice that in full wave bridge rectifier.
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To protect the diodes in a rectifier and capacitor input filter circuit it is necessary to use
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In a full bridge circuit supplying an RLC under damped circuit
- A. the waveshapes of output voltage and load current are square
- B. the waveshapes of output voltage and load current are sinusoidal
- C. the waveshapes of output voltage is square but the waveshape of load current is nearly sinusoidal
- D. none of the above
- Correct Answer: Option C
In a dual converter operated in circulating current mode, the circulating current flows
- A. when load current is zero
- B. when load current is non-zero
- C. even when load current is zero
- D. none of the above
- Correct Answer: Option C
Assertion (A): Thyristors can be used in controlled heating, excitation systems of alternators, speed control of motors and HVDC Reason (R): A static var system using thyristors is very commonly used in high voltage ac systems.
- 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 B
- Correct Answer: Option B
Thyristors can be used for control of
- A. dc separately excited motor
- B. dc shunt motor
- C. dc series motor
- D. all of the above
- Correct Answer: Option D
In a single phase cycloconverter with centre tapped transformer
- A. all thyristors carry currents for equal duration
- B. the durations of currents in all thyristors may or may not be equal
- C. the durations of currents in all thyristors cannot be equal
- D. the duration of currents in all thyristors must be equal for satisfactory operation
- Correct Answer: Option B
From which instant is the turn off time of a thyristor defined
- A. when anode voltage becomes zero
- B. when anode current becomes zero
- C. when both anode voltage and current become zero
- D. none of the above
- Correct Answer: Option B
As compared to a p-n junction diode
- A. a schottky diode has lower cut in voltage and lower reverse saturation current
- B. a schottky diode has higher cut in voltage and higher reverse saturation current
- C. a Schottky diode has lower cut in voltage and higher reverse saturation current
- D. a schottky diode has higher cut in voltage and lower reverse saturation current
- Correct Answer: Option C
In disc mounting of SCR
- A. SCR is clamped on one side of disc shaped heat sink
- B. SCR is clamped between two disc shaped heat sinks
- C. The SCR has low current rating
- D. None of the above
- Correct Answer: Option B