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# Quiz on GATE previous questions| BJT

1)For BJT, the common base current gain $\alpha$=0.98  and the collector base junction reverse bias saturation current $I_{CO}$= 0.6 uA. This BJT is connected in the common emitter mode and operated in the active region with base drive current $I_B$= 20 uA. The collector current $I_C$ for this mode of opertation is

a) 0.98 mA     b) 0.99 mA    c) 1 mA d) 1.01 mA

2)

In the circuit, what is the value of Current $I_o$

a) 0.5 mA   b) 2 mA    c)9.3 mA   d) 15 mA

3) What is the most noticeable effect of a small increase in temperature in the common emitter connected BJT?

a) Increase in $I_cbo$

b) Increase in output resistance

c) Decrease in forward current gain

d) Increase in forward current gain

4) In a common emitter amplifier, the unbypassed emitter resistance provides

a) Voltage shunt feedback

b) Current series feedback

c) negative voltage feedback

d) positive current feedback

5) If the differential voltage gain and common mode voltage gain of a differential amplifier are 48 dB and 2 dB respectively, then the common mode rejection ratio is

a) 23 dB

b) 25 dB

c) 46 dB

d) 50 dB

6) The gain of the amplifier(BJT) falls at higher frequencies due to

a) Internal capacitance of the device

b) Coupling capacitor at the input

c) Skin effect

d) Coupling capacitor at the output

7) Three identical amplifiers with each one having a voltage gain of 50 , input resistance of 1k ohm and output resistance of 250 ohm are cascaded. The circuit gain of the combined amplifier is

a) 49 dB

b) 51 dB

c) 98 dB

d) 102 dB

8) In a common emitter BJT amplifier , the maximum usable supply voltage is limited by

a) Avalanche breakdown of base emitter junction

b) Collector- Base breakdown voltage with emitter open

c) Collector – Emitter breakdown voltage with base open

d) Zener breakdown voltage of the emitter base junction