Question

A transistor is used in common-emitter mode in an amplifier circuit. When a signal of 10 mV is added to the base-emitter voltage, the base current changes by 10 mA and the collector current changes by 1.5 mA. The load resistance is 5 kW. The voltage gain of the transistor will be ___.

Answer 1

ri=$\frac{10mV}{10\mu A}=10^3\Omega$
$\beta= \frac{1.5mA}{10\mu A}=150$
Av=($\frac{R_0}{r_i}$)$\beta$=($\frac{5000}{1000}$)$\times 150$
=750