In a transistor circuit, when the base current is increased by 50 micro-amperes keeping the collector…
In a transistor circuit, when the base current is increased by 50 micro-amperes keeping the collector voltage fixed at 2 volts, the collector current increases by $1 \mathrm{~mA}$. The current gain of the transistor is
$20$
$40$
$60$
$80$
Solution
Increase in base current
$
\Delta I_b=50 \mu \mathrm{A}
$
Increase in collector current $\Delta I_c=1 \mathrm{~mA}$
Current gain $\beta=\frac{\Delta I_c}{\Delta I_b}=\frac{1 \times 10^{-3}}{50 \times 10^{-6}}=\frac{10^3}{50}=20$