The input resistance of a siIicon transistor is 100`Omega` . Base current is changed by 40`mu` A which resuIts in a change in coIIector current by 2 mA. This transistor is used as a common emitter ampIifier with a Ioad resis- tance of 4 k `Omega`. What is the voItage of the ampIifier?

Explanation

Voltage gain : `(DeltaV_(0))/(DeltaV_(i))=(DeltaI_(C)R_(L))/(DeltaI_(B)R_(B))=beta(R_(I))/(R_(I))`
Load resistance `R_(L)=4kOmega=4000Omega`
Input resistance `R_(B)=1000Omega`
`:.` Current gain =`(DeltaI_(C))/(DeltaI_(B))=(2"mA")/(40muA)=(2xx10^(3))/(40)=5`
`:.` Voltage gain `=50xx(4000)/(100)=2000`