Q.1
For a certain SCR configuration, the below shown waveform is obtained. Find the value of the average output voltage with α =& Vs =V.
Questionpower-electronics-questions-answers1.jpg
  • a) 50.27 V
  • b) 100.8 V
  • c) 140 V
  • d) 120 V
Q.2
A single-phase half wave circuit has Vs =V with a R load ofΩ. Find the average load current at α = 30°.
  • a) 1.45 A
  • b) 0.57 A
  • c) 0.96 A
  • d) 2.3 A
Q.3
A single phaseV, 1 kW heater is connected across a 1-phaseV,Hz supply through an SCR. The firing angle of the SCR is adjusted to give a rms voltage ofV. Find the power absorbed by the heater element.
  • a) 250 watts
  • b) 1 kW
  • c) 454 watts
  • d) 378 watts
Q.4
For a single phase half-wave thyristor circuit with R load, the power delivered to the resistive load is
  • a) (average load voltage) x (average load current)
  • b) (rms supply voltage)2/R
  • c) (rms load voltage)2/R
  • d) (average load voltage)/R
Q.5
For a single phase half-wave thyristor circuit with R load, the input power factor is given by
  • a) rms source voltage/total rms line current
  • b) rms input power/power delivered to the load
  • c) cos α
  • d) power delivered to load/input VA
Q.6
For the below shown circuit,
Questionpower-electronics-questions-answers6.jpg
  • a) gradually rising
  • b) going from positive to negative
  • c) gradually decaying
  • d) zero
Q.7
For the below shown circuit,
Questionpower-electronics-questions-answers7.jpg
  • a) load voltage & load current are both zero
  • b) only load voltage is zero
  • c) only load current is zero
  • d) both are non zero & non negative
Q.8
In case of a single-phase half-wave circuit with RL load, with firing angle α and extinction angle β, the conduction angle γ can be written as
  • a) γ = β+α
  • b) γ = β-α
  • c) γ = β/α
  • d) γ = α/β
Q.9
For a half-wave single phase thyristor rectifier circuit with any type of load the _______ + _________ waves must ideally give the supply voltage waveform.
Questionpower-electronics-questions-answers9.jpg
  • a) load voltage, load current
  • b) load voltage, thyristor voltage
  • c) supply current, load voltage
  • d) supply current, thyristor voltage
Q.10
In case of a single-phase half-wave circuit with RL load, with firing angle α and extinction angle β, the thyristor is reversed biased from
  • a) β to α
  • b) β to 2π+α
  • c) β to 2π
  • d) β to 2β
0 h : 0 m : 1 s