Question

When the resistance measured between p and n ends of a p-n junction diode is high, it can act as a/an:

• A. Resistor
• B. Inductor
• C. Capacitor
• D. Switch

Answer 1

Answer: (C)

Capacitor

Answer 2

When a p-n junction diode has high resistance between its p and n ends, it exhibits characteristics similar to a capacitor. This occurs because:

1. The depletion region that forms acts as a dielectric material
2. The p and n regions effectively function as parallel conducting plates
3. The structure can store electrical charge
4. It shows high resistance to current flow, especially in reverse bias

This behavior is known as junction capacitance or transition capacitance in semiconductor physics. The other options are incorrect because:

• (A) Resistor: While there is high resistance, the charge storage capability is not characteristic of a resistor
• (B) Inductor: The diode doesn't store energy in a magnetic field
• (D) Switch: Though a diode can act as a switch in some applications, high resistance state specifically exhibits capacitive behavior

Therefore, option (C) Capacitor is the correct answer.