A transistor is used in common-emitter mode in an amplifier circuit

PHYSICS · Multi-part · A Level · Physics · Electronics · Electronics

Problem

A transistor is used in common-emitter mode in an amplifier circuit. When a signal of

20\,\mathrm{mV}

is added to the base-emitter voltage, the base current changes by

20\,\mu\mathrm{A}

and the collector current changes by

2\,\mathrm{mA}

. The load resistance is

5\,\mathrm{k}\Omega

. Calculate (a) the factor

\beta

(b) the input resistance

R_{\mathrm{in}}