Question

The graph shows the variation of current with voltage for a p-n junction diode.

Estimate the dynamic resistance of diode at V = −0.6 volt.

Answer 1

From the graph, at V₁ = −0.6 V, the reverse current (I₁) is approximately 2 μA, and at V₂ = −08 V, the reverse current (I₂) is approximately 2.2 μA.

Using the formula for dynamic resistance:

r_d = `(Delta V)/(Delta I)`

= `(V_2 - V_1)/(I_2 - I_1)`

= `-(-0.8 V - (-0.6 V))/((2.2 - 2.0) xx 10^-6 A)`

= `-(0.2 V)/(0.2 xx 10^6 A)`

= 1 MΩ

The estimated dynamic resistance at V = −0.6 V is 1 MΩ (1 Mega-ohm).