# A BJT current source is given in the figure. Assume the Si-PNP transistor to operate in the active region. The value of current I in mA is

### Right Answer is:

2.15

#### SOLUTION

For given BJT current source operating in active region

I_{E} = I_{C} + I_{B}

As the value of β is not given we assume that β is very large

Therefore, I_{B} = 0

⇒ I = I_{E} = I_{C}

Applying the KVL loop at the input side through the Zener diode as it regulates the voltage across the emitter resistance.

V_{Z} −I_{E}R_{E} − V_{BE} = 0

∵ For PNP transistor potential barrier is −0.7 V

5 − I_{E }× 2 − 0.7 = 0

2 × 10^{3} × I_{E} = 4.3

I_{E} = 2.15 mA

∵ The value of β is not given we assume that β is very large

∴ **I _{E} = I_{C} = I = 2.15 mA**