A p-n junction diode’s dynamic conductance is directly proportional to Options :The applied voltageThe temperatureIt’s currentThe thermal voltage

To determine what the dynamic conductance of a p-n junction diode is directly proportional to, let's analyze the relationships:

1. Dynamic Conductance: This is defined as the change in current ($I$) with respect to the change in voltage ($V$) at a given operating point, mathematically expressed as $g_d = \frac{dI}{dV}$.

2. The Applied Voltage: The dynamic conductance will vary with the voltage but is not directly proportional to it in a linear manner.

3. The Temperature: The increase in temperature typically affects carrier concentration and mobility, thereby influencing current and hence dynamic conductance, but not in a direct proportional relationship across all conditions.

4. Its Current: In a diode, dynamic conductance is closely related to the current flowing through it due to the exponential relationship given by the Shockley diode equation. Thus, it is true that dynamic conductance substantially depends on the current.

5. The Thermal Voltage ($V_T$): Although this sets a reference for how current changes with voltage, conductance is more directly affected by the current itself.

Conclusion

Therefore, the option that is a direct proportional relationship is:

The current.

So, the correct answer is: It’s current.