Physics - Semiconductors Question with Solution | TestHub

The AC current gain $\beta$ is given by the ratio of the change in collector current to the change in base current:

$\beta =\frac{\Delta I_C}{\Delta I_B}$

Substituting the given values:

$\beta =\frac{5\text{mA}}{0.2\text{mA}}=25$

The voltage gain $A_v$ of a transistor amplifier is given by:

$A_v=\beta \times \frac{R_L}{R_{in}}$

Substituting the known values into the formula:

$75=25\times \frac{R_L}{2\text{k}\Omega }$

$\frac{R_L}{2\text{k}\Omega }=\frac{75}{25}=3$

$R_L=3\times 2\text{k}\Omega =6\text{k}\Omega$

Answer: $6\text{k}\Omega$