Lead count of a power semiconductor diode How many external leads (terminals) does a standard power semiconductor diode have?

Introduction / Context:
Power semiconductor diodes are two-terminal devices used for rectification, freewheeling, and snubbing. Recognizing terminal count is basic device knowledge needed for circuit identification and troubleshooting.

Given Data / Assumptions:

• Device under consideration is a standard power diode, not a controlled switch.
• Terminals are typically labeled anode and cathode.

Concept / Approach:
A diode conducts current primarily in one direction (anode to cathode) and blocks in the reverse direction. It therefore has exactly two external terminals—unlike controlled devices (thyristors, transistors) that include a third control terminal.

Step-by-Step Solution:
Identify device type: diode (uncontrolled).Confirm terminals: anode and cathode.Hence, the number of leads is 2.

Verification / Alternative check:
Datasheets and package drawings (stud, press-fit, TO-packages) show two terminals; mounting hardware does not constitute an electrical terminal.

Why Other Options Are Wrong:
3 or 4 leads: Would imply additional control or sensing terminals; not a standard diode.

Common Pitfalls:
Mistaking a diode module (with multiple diodes inside) for a single diode; the module may have more external connections but each diode element still has two terminals.

Final Answer:
2