Physics Question on Semiconductor electronics: materials, devices and simple circuits

Question

A transistor is operated in common emitter configuration at constant collector voltage VC = 1.5 V such that a change in the base current from 100 µA to 150 µA produces a change in the collector current from 5 mA to 10 mA. The current gain (β) is :

Answer 1

Solution

Transistor Current Gain ( $\beta$ ): $\beta$ (current gain) is given by the change in collector current ( $\triangle \text{I}_C$ ) divided by the change in base current ( $\triangle \text{I}_B$ ).
In this case, $\triangle \text{I}_C$ = 10 mA - 5 mA = 5 mA

and $\triangle \text{I}_B$ = 150 μA - 100 μA = 50 μA.

So, $\beta$ = $\frac{\triangle \text{I}_C}{\triangle \text{I}_B}$ = $\frac{5 mA}{50 \mu A}$ = 100.

Therefore, the correct option is (C): 100