Power Electronics Viva Questions with Answers

Power Electronics Viva Questions and Answers

[1] What are the advantages and disadvantages of Flyback converter?
Advantages:
(1) No inductor is required at the output which is compulsory is the other converters topology.
(2) Number of components are less.

Disadvantages:
(1) Useful for low power applications(50W to 100W)
(2)  Output load is compulsory otherwise output capacitance may get overcharge.

[2] What is meant by Constant Current Source?
A voltage source that has a very high internal impedance as compared with external load impedance is considered as a Constant Current Source( the source which can provide constant current to the load).

[3] What is the difference between silicon diode and germanium diode?

  • Generally Silicon diodes have higher PIV (Peak Inverse Voltage) and current rating than germanium diodes. 
  • Peak Inverse Voltage (PIV) ratings
    for silicon diodes is nearly 1000 V, whereas
    for germanium diodes is maximum 400 V only.
  • Silicon diodes can work in wider temperature ranges. Temperature range
    for Silicon diodes is about 200°C, whereas
    for germanium diodes is maximum 100°C.
  • The disadvantage of silicon diode is the higher knee voltage (forward-bias voltage required to reach the region of upward swing). Typically the knee voltage
    for Silicon diodes is 0.7V, whereas
    for germanium diodes is 0.3V.

[4] What is the difference between Resistor, Rheostat and Potential Divider?
Resistor:
A fixed resistor connected permanently in the circuit for the purpose of limiting the current is called as resistor.

Rheostat:
A variable resistance with a sliding contact is known as rheostat. The current flowing through the circuit is restricted by inserting and varying the resistance with the help of the sliding contact.

Potential divider:
When a resistance is used to develop a voltage drop, it is called as a potential divider.

[5] What are the characteristics of ideal Opamp?

  • Infinite open loop voltage gain
  • Infinite input impedance
  • Zero output impedance
  • Infinite Bandwidth
  • Zero offset voltage

Read More:

Comparison of Inverters: VSI vs CSI
How to provide reverse voltage protection?
What is Power Electronics?
Power Electronics Interview Questions and Answers: Set-8

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