The input resistance of a silicon transistor is `100 Omega`. Base current is changed by `40 muA` 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 `4k Omega`. The voltage gain of the amplifier is

Options

A. 2000
B. 3000
C. 4000
D. 1000

Answer

A

Explanation

Here,
Input resistance, `R_(i)=100Omega`
Change in base current, `DeltaI_(B)=40muA`
Change in collector current, `DeltaI_(C)=2mA`
Load resistance, `R_(L )=4kOmega=4xx10^(3)Omega`
Current gain, `beta=(DeltaI_(C ))/(DeltaI_(B))=(2mA)/(40muA)=(2xx10^(-3))/(40xx10^(-6)A)=50`
Voltage gain of the amplifier is
`A_(V)=beta(R_(L))/(R_(i))=50xx(4xx10^(3))/(100)=2000`