A BJT has values of α = 0.9985 and IC = 15 mA. What is the value of IB for the component?
A) 22.5 μA
B) 15.15 mA
C) 14.85 mA
D) None of these are correct.

Question

Quizplus · Accepted Answer

The base current $I_B$ can be calculated using the relation between the collector current ($I_C$), the current gain ($\alpha$), and $I_B$, given by $I_C = \alpha I_E + I_B$, where $I_E$ is the emitter current. Since $I_E = I_C + I_B$ and $\alpha = \frac{I_C}{I_E}$, rearranging for $I_B$ gives $I_B = I_C(1 - \alpha) / \alpha$. Substituting the given values, $I_B = 15mA \times (1 - 0.9985) / 0.9985 = 22.5 \mu A$.

A BJT Has Values of α = 0