The input resistance of a silicon transistor is `665 Omega` when base current is changed by `15muA`, the collector current changes by 2mA. In a common emitter amplifier load resistance is `5k Omega`. Calculate current gain `beta_(ac)`

Explanation

`R_(i)= 655Omega`
`Delta I_(b)= 15muA= 15 xx 10^(-6)A, Delta I_(c) =2mA= 2 xx 10^(-3)A, R_(L) = 5k Omega = 5000Omega, beta_(ac)`= ?
Transconductance= `g_(m)`= ?
`A_(v)`= ? `beta_(ac)= (Delta I_(c))/(Delta I_(b))= (2 xx 10^(-3))/(15 xx 10^(-6))= (2000)/(15)`
`beta_(ac)= 133.33`
`A_(v)= beta_(ac)xx (R_(L))/(R_(i)) = 133.33 xx (5000)/(665)`
`A_(v)= 1002.48`
Transconductance `=g_(m)= (beta_(ac))/(R_(i))`
`g_(m)= (133.33)/(665)= 0.2005 Omega^(-1)`