41. An UJT, the p-type emitter is . . . . . . . . doped
42. A single-phase full-wave AC phase controller feeds power to a resistive load of 100 Ω from a 220 V, 50 Hz supply. What will be the rms output voltage at delay angles $${\alpha _1} = {\alpha _2} = \alpha = \frac{\pi }{2}$$ of both transistors?
43. Consider the following statements:
A four-layer PNPN device having two gate leads can turned on by applying a
1. positive current pulse to the cathode gate
2. positive current pulse to the anode gate
3. negative current pulse to the anode gate
4. negative current pulse to the cathode gate
Which of these statements is/are correct?
A four-layer PNPN device having two gate leads can turned on by applying a
1. positive current pulse to the cathode gate
2. positive current pulse to the anode gate
3. negative current pulse to the anode gate
4. negative current pulse to the cathode gate
Which of these statements is/are correct?
44. A Silicon Controlled Resistor (SCR) is made up of silicon and not germanium because
45. An a.c. regulator can be designed with
46. The gate current required to turn on an SCR is
47. A freewheeling diode in a phase controlled rectifier
48. Consider the following statements: An SCR, from its OFF state, can be made ON by-
1. increasing its anode voltage
2. increasing its gate current
3. decreasing its gate voltage
4. decreasing its anode current
Which one of the following statements is correct?
1. increasing its anode voltage
2. increasing its gate current
3. decreasing its gate voltage
4. decreasing its anode current
Which one of the following statements is correct?
49. Power diode are used with
50. Match List-I with List-II and select the correct answer using the options given below:
List-I (SCR Rating)
List-II (Protective element)
a. di/dt limit
1. Snubber circuit
b. dv/dt limit
2. Heat sink
c. i2t limit
3. Series reactor
d. Junction temperature limit
4. Fuse
| List-I (SCR Rating) | List-II (Protective element) |
| a. di/dt limit | 1. Snubber circuit |
| b. dv/dt limit | 2. Heat sink |
| c. i2t limit | 3. Series reactor |
| d. Junction temperature limit | 4. Fuse |
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