Question

A common emitter amplifier with bypass emitter resistance has collector current equal to 2mA and emitter current equal to 2.01 mA. Its input resistance is approximately equal to _____k$\Omega$

• A. 2.6

Answer 1

The correct option is A 2.6
Input resistance, $r_{\pi }=\frac{V_T}{I_{BQ}}$

now, $I_{BQ}=I_E-I_C=(2.01-2)mA=0.01mA$

$r_{\pi }=\frac{26\times {10}^{-3}}{0.01\times {10}^{-3}}=2600\Omega =2.6k\Omega$