Question

Consider the transistor circuit shown below, both transistors are identical and having $\beta =100$
Then the voltage $\left(V_A\right)$ is (Assume $V_{BE}=0.7V)$

• A. 3.75 V
• B. 5.45 V
• C. 4.5
• D. 3.8 V

Answer 1

The correct option is C 4.5

For the circuit shown above,

Emitter current of both transistor is ,

$I_E=0.5mA$

$\therefore$Base current of both transistor is ,

$I_B=\frac{0.5mA}{\beta +1}=\frac{0.5mA}{101}=4.95\mu A$

Apply KVL in the loop shown in above figure,

$\therefore V_A=10K\times 4.95\mu +0.7+0.7+10K\times 4.95\mu +3$

$=4.499$

$V_A=4.5V$