MCQ
2541. The most commonly used semiconductor is-
germanium
carbon
sulphur
silicon
2542. RC coupling is used for---amplification.
voltage
power
current
none
2543. 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
2544. The maximum efficiency of a half-wave diode rectifier is --
50%
25%
40.0%
81.2%
2545. 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
2546. 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
2547. If a power supply has no-load and full-load voltages of 30V and 25V respectively, then the percentage voltage regulation is:
10%
20%
15%
25%
2548. The reverse current in a diode is of the order of—
KA
A
mA
uA
2549. A zener diode is destroyed if it-
is forward biased
is reverse biased
carriers more than rated current
none of the above
2550. In the normal operation of an SCR, anode is-- with respect to cathode.
at zero potential
negative
positive
none of the above
2551. A PN junction acts as a--
ব্যাখ্যা: The PN junction is conduct with forward bias only. It means they conduct in only one direction (Current flows from P to N) That's why PN Junction acts as unidirectional twitch
unidirectional switch
bidirectional switch
controlled switch
none of the above
2552. 1 db corresponds to --- changes in voltage level.
12%
20%
80%
26%
2553. The point of intersection of de and ac load lines is called-
saturation
operating
cut off
none of these
2554. For highest power gain, one would use-- configuration.
ব্যাখ্যা: For highest power gain, CE configuration is used. In CE configuration, biasing capacitor is used to balance the operating point to obtain highest power gain
CE
CB
CC
none of these
2555. 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
2556. 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
2557. When transistor is used as an amplifier, it is operated in the:
Cut off region
Saturation region
Active region
Both a and b
2558. In an LC oscillator, the frequency of oscillation is:
Proportional to LC
Proportional to square root of LC
Inversely proportional to the square root of LC
Independent of the value of LC
2559. Which causes the barrier layer in a PN Junction--
doping
barrier potential
recombination
ions
2560. Transistor biasing represents --conditions.
ac
both ac & dc
dc
none