What are the two most commonly-used specifications for a junction diode?

The specifications that are most commonly used for a junction diode are indeed maximum forward current and peak inverse voltage (PIV).

Maximum forward current refers to the greatest amount of current that a diode can handle when it is in the conducting state (forward-biased). Exceeding this current can lead to thermal runaway and damage the diode. This specification is crucial for ensuring that the diode can safely pass the necessary current in a circuit without failure.

Peak inverse voltage (PIV), also known as reverse breakdown voltage, represents the maximum voltage that can be applied to a diode in the reverse direction without causing it to conduct in reverse and potentially becoming damaged. Understanding the PIV allows engineers to design circuits that avoid exceeding this threshold during operation, which is essential for the reliability and longevity of the diode.

These two specifications provide vital information about the operational limits of a junction diode, allowing designers to select appropriate diodes for specific applications based on the expected current and voltage conditions.