MCQ
21. Approximately how many milliamperes of current flow through circuit with a 40V source and 6.8 ΚΩ of resistance?
27.2 mA
5.9 mA
59 mA
590 mA
22. An SCR is a --triggered device.
Voltage
current
Voltage as well as current
None of the above
23. The purpose of a gate is to---
deliver molten metal into the mold cavity.
act as a reservoir for the molten metal.
feed the molten metal to the casting in order to compensate for the shrinkage.
deliver molten metal from pouring basin to gate
24. The reverse current in a diode is of the order of—
KA
A
mA
uA
25. A voltage divider consists of two 100k resistors and a 12V source. What will the output voltage be if a load resistor of 1 MQ is connected to the output?
0.57V
12V
5.7 V
6 V
26. The battery connections required to forword bias a pn junction are-
+ve terminal to p and -ve terminal to n
-ve terminal to pand+ ve terminal to n
-ve terminal to p and-ve terminal to n
+ve terminal to pand+ ve terminal to n
27. As the temperature of a transistor goes up the base-emitter resistance-
ব্যাখ্যা: As temperature increase, the thermal runway properly of transistor becomes more prominent and base-emitter resistance will decreases.
decreases
increases
remains the same
none
28. What is the approximate resistance setting of a rheostat in which 650 mA of current flows with a 150V source?
9.7 Ω
97 Ω
23 Ω
230 Ω
29. The output frequency of a full wave rectifier is-
Same as the input frequency
One-half of the input frequency
Double of the input frequency
Independent of the input frequency
30. If the ac supply is 50Hz, what will be the ripple frequency out of the full wave rectifier?
50Hz
100Hz
60Hz
20Hz
31. If the temperature of the diode increases, then leakage current-
Remains same
Increases
Decreases
Becomes zero
32. A zener diode is destroyed if it-
is forward biased
is reverse biased
carriers more than rated current
none of the above
33. In an SCR circuit, the generally --that of breakover voltage.
Equal to
Greater than
Less than
None of the above
34. An SCR has-semiconductor layers.
Two
Three
Four
None of the above
35. Noise factor of a ideal amplifier is---
ব্যাখ্যা: There is no noise in a ideal amplifier. So, noise factor is 0 dB
0dB
5dB
0.5dB
10dB
36. The parallel combination of a 470 Ω resistor and a 680 Ω resistor is in series resistors with the parallel combination of four 2k Ω The total resistance is-
1.650 Ω
1.0782 Ω
77.8Ω
778 Ω
37. An SCR has PN junctions.
Two
Four
Three
None of the above
38. An SCR is turned off when-
Anode current is reduced to zero.
Gate voltage is reduced to zero.
Gate is reverse biased.
None of the above.
39. 1 db corresponds to --- changes in voltage level.
12%
20%
80%
26%
40. In the normal operation of an SCR, anode is-- with respect to cathode.
at zero potential
negative
positive
none of the above