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BPE
List different turn-on methods of SCR.
Ans: Forward voltage triggering dv/dt triggering. Temperature triggering Light/illumination /radiation triggering. Gate triggering
State two applications of GTO.
Ans: Applications of GTO: (Any two) Variable speed motor drives. High power inverter. Traction. DC drives or DC choppers. AC drives. AC …
Explain with the characteristics the effect of gate current on break over voltage of SCR.
Ans: Effect of gate current on break over voltage of SCR: Explanation: The voltage at which the SCR comes into conduction without any gate current…
Describe the operation of PUT as relaxation oscillator.
Ans: PUT Relaxation oscillator: Waveforms of PUT relaxation oscillator Operation: As the biasing voltage Edc is applied to the circuit , capacitor…
Explain with sketch the operation of power MOSFET.
Ans: Circuit diagram: (Structure of power MOSFET as shown below or any other equivalent can be considered ) V-I characteristics: Operation: Figure…
Explain operation of series inverter with neat circuit diagram and waveform.
Ans: Working: When S1 (T1) is triggered the capacitor starts charging with left side plate positive with respect to right and when the voltage on cap…
Describe the operation of single phase half wave controlled rectifier with RL load.
Ans: Circuit diagram: Working: During positive half cycle of input voltage, thyristor T is forward biased but it does not conduct until gate signal i…
Explain with circuit diagram the operation of class C commutation.
Ans: Circuit Diagram: Working:- At first, when the SCR1 is triggered load current flows IL starts flowing through (Vdc+, RL, SCR1, Vdc-). At the sa…
Explain with circuit diagram the operation of emergency lighting system.
Ans: Working:- Fig. above shows a simple emergency lighting circuit. The 230v ac supply is applied as input. Supply is stepped down using a Center ta…
A single phase full wave controlled rectifier is supplied with a voltage V = 23 sin 314t.if firing angle ‘α’ is 30° . Find:
(i) Average dc output voltage (ii) Load current for the load resistance of 100 Ω Ans:
Explain class B commutation with neat circuit diagram
Ans: Explanation: This is also a self commutation circuit in which commutation of SCR ’T’ is achieved automatically by L and C components. When th…
Explain with circuit diagram and waveform the operation of single phase center tapped full wave controlled rectifier with R load.
Ans: Working: For the positive half cycle of applied voltage, SCR 1 conducts during the period α to π radians where α is the firing angle. …