Assuming an operating temperature T = 300 K and corresponding

Assuming an operating temperature T = 300 K and corresponding V_T = 26 mV, what is the change in semiconductor silicon diode forward voltage V_D to produce a 10: 1 change in diode current I_D, while operating in the forward bias region (<25mA)?

We know that diode current equation is given by

I = I₀		e	V	- 1
			V_T

I = I₀		e	V
			V_T

[For forward bias]
Since, = 2 for Si diode

I = I₀		V
		2V_T

Where, I = Forward current
I₀ = Leakage current
V = Applied forward voltage
V_T = Volt equivalent of temperature (Given V_T = 26 mV)

From equation		I₁	e	V_{1_{– V₂}}
		I₂		2V_T

Given		I₁	=	10	then
		I₂		1

10 e	V	(V = change in forward voltage)
	2V₂

or 10 log_e 10 =	V	log_e e
	2V_T

or V 2V_T log_e10
2 × 26 mV × log_e10 119·7 mV
Hence alternative (B) is the correct choice.