What will be the input independence Zi for the network shown

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What will be the input independence Z_i for the network shown below?

1. 560.5 Ω
2. 56.05 Ω
3. 937 Ω
4. 617.7 Ω

Correct Option: A

I_B =	V_CC - V_BE
	R_F + βR_C

=	9 - 0.7	= 11.53 A
	180 kΩ + 200 × 2.7 kΩ

I_E = (β + 1) I_B = 201 × 11.53 A = 2.32 mA

r_e =	26 mV	=	26 mV	= 11.21 Ω
	I_E		2.32 mA

∴ Z_i =	r_e				=	11.21	= 560.5 Ω
	1	+	R_C			0.005 + 0.015
	β		R_F