Consider the circuit shown in figure given below. If the

Consider the circuit shown in figure given below. If the β of the transistor is 30 and ICBO is 20 nA and the input volt age is + 5 V, then transistor would be operating in

V_TH =	12 × 15	+ v_i ×	100
	15 + 100		115

For v_i = 5V
V_TH = 2.78 volts,
R_TH = (15//100) = 13 kΩ

Minimum value of I_B =	V_TH - V_BE
	13 kΩ

=	2.78 - 0.7	= 0.16 mA
	13

and I_C = βI_B = 30 × 0.16 = 4.8 mA

Now , I_C(sat) =	V_CC - V_CE , sat
	R_e

=	12 - 0.2	= 5.36 mA
	2.2 kΩ

Then , I_B(sat) =	5.36 mA	= 0.178 mA
	30

As, I_B (sat) > I_B_(min)
The transistor is in active region.