Answer to Question #227700 in Electric Circuits for samsam

Question

Given that VS = 3V, VBE = 0.3V, IC = 9mA, and R1 = 1kΩ, calculate the base current of the transistor Q1 using KVL. Also find the current gain ( ) of the transistor Q1

Answer 1

Using KVL

$3=0.3+1000I_E\\ 2.7=1000I_E\\ I_E=2.7mA\\ I_E=I_C+I_B\\ I_B=I_E-I_C=2.7-9=-6.3mA\\$

Base current is 6.3mA

Current gain beta $\beta$ is given by

$\beta=\dfrac{I_C}{I_B}=\dfrac{9}{6.3}=1.4$