A transistor with `alpha = 0.98 ` is operated in common emitter circuit with a load resistance of `5kOmega` . If the dynamic resistance of the base emitter junction is `7Omega` , the voltage gain and power gain will be :

Options

A. `3500, 1.715 xx10^5`
B. `4000,2.715xx10^5`
C. `2500,1.215 xx10^5`
D. none of these

Answer

A

Explanation

`beta = alpha/(1-alpha) = (0.98)/(1-0.98)=49`
Voltage gain `A_v=beta (R_("out"))/(R_("in"))=(49xx5xx10^3)/70=3500`
Power gain = voltage gain `xx beta = 3500 xx 49`
` = 1.715xx10^5`