Image
1.0.0
MCQ
7241. A zener diode is destroyed if it-
is forward biased
is reverse biased
carriers more than rated current
none of the above
7242. Transistor biasing represents --conditions.
ac
both ac & dc
dc
none
7243. 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%
7244. The maximum efficiency of a half-wave diode rectifier is --
50%
25%
40.0%
81.2%
7245. 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
7246. Emitter follower is used for--
Impedance matching
Current gain
Voltage gain
None of the above
7247. The most commonly used semiconductor is-
germanium
carbon
sulphur
silicon
7248. A PN junction acts as a--
unidirectional switch
bidirectional switch
controlled switch
none of the above
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
7249. When transistor is used as an amplifier, it is operated in the:
Cut off region
Saturation region
Active region
Both a and b
7250. 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
7251. When there is no forbidden region between the conductance band and valence band, the substance is called:
Semiconductor.
conductor
superconductor
insulator
7252. 1 db corresponds to --- changes in voltage level.
12%
20%
80%
26%
7253. 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
7254. In the normal operation of an SCR, anode is-- with respect to cathode.
at zero potential
negative
positive
none of the above
7255. The point of intersection of de and ac load lines is called-
saturation
operating
cut off
none of these
7256. As the temperature of a transistor goes up the base-emitter resistance-
decreases
increases
remains the same
none
ব্যাখ্যা: As temperature increase, the thermal runway properly of transistor becomes more prominent and base-emitter resistance will decreases.
7257. For highest power gain, one would use-- configuration.
CE
CB
CC
none of these
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
7258. RC coupling is used for---amplification.
voltage
power
current
none
7259. Noise factor of a ideal amplifier is---
0dB
5dB
0.5dB
10dB
ব্যাখ্যা: There is no noise in a ideal amplifier. So, noise factor is 0 dB
7260. Which causes the barrier layer in a PN Junction--
doping
barrier potential
recombination
ions