Question

What is the current through the circuit and the potential difference across the diode shown in the figure. The drift current for the diode is \(30\,\mu A\).

• A. \(30\,\mu A,\, 5.99\,V\)
• B. \(30\,\mu A,\, 5\,V\)
• C. \(20\,\mu A,\, 6\,V\)
• D. \(20\,\mu A,\, 5.99\,V\)

Hint:

In reverse bias, diode current \(\approx\) constant (drift current), voltage mostly appears across diode.

Answer 1

The Correct Option is A

Concept: In reverse bias, diode current is approximately equal to drift current (very small and constant).

Step 1: Identify diode condition.
From the circuit, diode is reverse biased. \[ I = I_{\text{drift}} = 30\,\mu A \]

Step 2: Voltage drop across resistor.
\[ V_R = IR = (30 \times 10^{-6})(20) = 6 \times 10^{-4}\,V = 0.0006\,V \]

Step 3: Voltage across diode.
\[ V_D = 6.0 - 0.0006 = 5.9994 = 5.99\,V \]