A common emiiter amplifier has voltage gain 50 and current gain is 25. The power gain of the amplifier is:

Options

A. 500
B. 1000
C. 1250
D. 100

Answer

C

Explanation

AC power gain is ratio of change in output power to the chagne in input power.
Ac power gain
`=("change in output power")/("change in input power")=(DeltaV_(c)xxDeltai_(c))/(DeltaV_(i)xxDeltai_(b))`
`=((DeltaV_(C))/(DeltaV_(i)))xx((Deltai_(C))/(Deltai_(b)))=A_(V)xxbeta_(AC)xx(200)/(100)`
`:. beta_(AC)=25`
Now, AC power gain `=A_(V)xxbeta_(AC)`
`=50xx25=1250`