Question

In a transistor ($\beta$ = 45), the voltage across 5 $k \Omega$ load resistance in collector circuit is 5V. The base current is

• A. 0.022 mA
• B. 0.978 mA
• C. 1.0 mA
• D. 2.5 mA

Answer 1

Answer: (A)

0.022 mA

Answer 2

$\beta = \frac{I_c}{I_b}$ $\therefore$ $\frac{I_c}{I_b}= 45$ Now $I_cR_L = 5V$ $\therefore$ $I_c = \frac{5}{R_L} = \frac{5}{5 \times 10^3} = 10^{-3}$ = 1 mA $\therefore$ $I_b = \frac{I_c}{45} = \frac{10^{-3}}{45} = 0.022 \times 10^{-3}A$ = 0.022 mA