169. In a SCR,
A. Gate current is directly proprotional to forward breakover voltage
B. as Gate current is raised, forward breakover voltage reduces
C. Gate current has to be kept on continuously for conduction
D. Forward breakover voltage is low in the forward blocking state
170. An inductance is inserted in the load circuit of SCR.
A. The turn on time of SCR is increased
B. Output voltage is reduced for the same firing angle
C. Conduction continues even after reversal of phase of input voltage
D. All the above
171. A half wave SCR controlled circuit with RL 50f1 conducts for 90? for an applied voltage of 800 V sinosoidal rms. If the SCR voltage drop is negligible, the power dissipated by the load is
A. 1800 W
B. 81 W
C. 52.36 W
D. OW
172. A half wave SCR controlled circuit with a load resistor RL = 1012 has an applied voltage of 300 V rms for a conduction angle of 60?. The reading of a true rms reading ammeter is
A. 9.37A
B. 11.97 A
C. 30A
D. OA
173. The ratio of gate current to condinuous anode current in a SCR to switch on is
A. 1:10
B. 1:100
C. 1:1000
D.>1 :10000
174. Select the correct statement(s)
A. The triac is a five-layer device.
B. The traic may be considered to consist
C. An additional lateral n-region serves p2 and pi ? n2 ? p2 ? n3. of two parallel section ni ? p1 ? n2 ?as control gate.
D. All of these
175. There are only silicon controlled rectifiers and not germanium because
A. Si is avilable as compared to Ge
B. only Si has as stable off state
C. Ge is very temperature sensitive
D. None of the above
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