Question 220: Semiconductors and Logic Gates

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 $$\mu$$A and the collector current changes by 1.5 mA. The load resistance is 5 k$$\Omega$$. The voltage gain of the transistor will be _________.

Accepted Answer

$${R_B} = {{10 	imes {{10}^{ - 3}}} \over {10 	imes {{10}^{ - 6}}}}$$
$$ = {10^3}\,\Omega $$
$$	herefore$$ $${A_v} = \left( {{{\Delta {I_C}} \over {\Delta {I_B}}}} ight) 	imes \left( {{{{R_C}} \over {{R_B}}}} ight)$$
$$ = {{1.5 	imes {{10}^{ - 3}}} \over {10 	imes {{10}^{ - 6}}}} 	imes {{5 	imes {{10}^3}} \over {1 	imes {{10}^3}}}$$
$$ = {{1.5 	imes 5} \over {10}} 	imes (1000)$$
$$ = 750$$

Semiconductors and Logic Gates

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 $\muA and the collector current changes by 1.5 mA. The load resistance is 5 k\Omega$. The voltage gain of the transistor will be _________.

Choose the correct answer: