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Power Electronic Class Test Question Paper

Unit 1 Q.1. Explain the two transistor analogy of SCR with equivalent circuit and give three application Q.2 Explain the operation of IGBT with VI and Switching characteristics. Q.3. Draw & explain the necessity of static and dynamic equalizing circuit for series connected SCR’s? Derive relations used for determining the valus of shunt resistor Rand capacitor C in this circuit. Q.4. describe the operation of LASCR, give its industrial applications. Draw circuit diagram and waveform of time delay using SCR & UJT for AC load. Q.5. what are the different methods to turn on the Thyristor? Q.6. draw V-I characteristics of DIAC. is DIAC equally sensitive in both the directions ? give two application of DIAC. Q.7. compare power BJT, power MOSFET and IGBT. Q.8. states any two features of power MOSFET which makes it suitable for medium power application. Q.9. Explain the role of the following power devices and their application  Power MOSFET IGBT GTO SCR Q.10. Describe the different...
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TRIAC [Triode for Alternating Current]

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  TRIAC What is a Triac? A Triac is defined as a three-terminal AC switch which is different from the other silicon-controlled rectifiers in the sense that it can conduct in both directions that is whether the applied gate signal is positive or negative, it will conduct. Thus, this device can be used for AC systems as a switch. This is a three-terminal, four-layer, bi-directional semiconductor device that controls AC power. The triac of maximum rating of 16 kw is available in the market. The figure shows the symbol of triac, which has two main terminals MT 1 and MT 2 connected in inverse parallel and a gate terminal. Construction of Triac Two SCRs are connected in inverse parallel with the gate terminal as common. Gate terminals is connected to both the N and P regions due to which gate signal may be applied which is irrespective of the polarity of the signal. Here, we do not have anode and cathode since it works for both polarities which means that device is bilateral. It consi...
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