devarshi-dt-logo

Question:

The input resistance of a silicon transistor is 100Ω. Base current is changed by 40µA which results in a change in collector current by 2 mA. This transistor is used as a common emitter amplifier with a load resistance of 4KΩ. The voltage gain of the amplifier is:

4000

3000

1000

2000

Solution:

For a common emitter amplifier,
Current gain (β) = ΔIC/ΔIB = (2 × 10⁻³)/(40 × 10⁻⁶)
β = 50
Voltage gain = β(Rout/Rin) = 50(4 × 10³/100)
Voltage gain = 2000