Question

Calculate the current through the circuit and the potential difference across the diode shown in figure. The drift current for the diode is 20 µA.
Figure

Answer 1

(a) It can be observed from the circuit diagram that there is a reverse bias of the diode with the applied voltage of 5.0 V.

Under the condition of reverse bias,

Circuit current = Drift current

So, the circuit current is 20 µA.

(b) Across the diode, the voltage will be equal to the battery’s voltage minus the drop of voltage across the 20-ohm resistor.

$\begin{array}{l}{\Rightarrow \mathrm{V}=5-\mathrm{iR}} \\\\{\Rightarrow \mathrm{V}=4.9996 \mathrm{V} \cong 5 \mathrm{V}}\end{array}$