Home/Class 12/Physics/

## QuestionPhysicsClass 12

The $$V-I$$  characteristic of a silicon diode is shown in the figure. Calculate the resistance of the diode at $$I_D=15\mathit{mA}$$  and $$V_0=-10V$$

Considering the diode characteristics as a straight line between $$I=10\mathit{mA}$$  to $$I=20\mathit{mA}$$  passing through the origin. we can calculate the resistance using Ohm's law.
From the curve, at $$I=20\mathit{mA},V=0.8V,1=10\mathit{mA}.V=0.7V$$
$$r_{fb}=\frac{\Delta V}{\Delta I}=\frac{0.1V}{10}\mathit{mA}=10\;\Omega$$
From the curve at $$V=-10V,I=-1\;\mu\text{A}$$
Therefore $$,r_{\mathit{rb}}=\frac{10V}{1\mathit{\mu A}}=1.0\times 10^7\Omega$$