Question

How does the dynamic resistance of diode vary with temperature?

• (A) Directly proportional
• (B) Inversely proportional
• (C) Independent
• (D) Directly to the square of temperature

Answer 1

The Correct Option is A

Explanation:
The dynamic resistance of the diode is directly proportional to the temperature.The dynamic resistance can be defined from the I-V characteristic of a diode in forward bias. It is defined as the ratio of a small change to voltage to a small change in current, i.e.$r_d=\left(\frac{\mathrm{\Delta }V}{\mathrm{\Delta }I}\right)=\frac{\eta V_T}{I}$$V_T=$ Thermal voltage$I=$ Bias current$V_T=\frac{kT}{q}$$V_T\propto T$The dynamic resistance is given by the inverse of the slope of $i-v$ characteristics as shown:

Hence, the correct option is (A).