Lead identification and polarity: Is the positive lead of a diode referred to as the cathode, or is the positive (forward) terminal the anode while the cathode is typically marked with a stripe?

Introduction / Context:Knowing diode polarity prevents wiring errors in rectifiers, clamps, protection networks, and logic steering circuits. A diode conducts when its anode is at a higher potential than its cathode by approximately the forward drop. Misidentifying the leads is a frequent beginner mistake that leads to non-functioning circuits or device damage.

Given Data / Assumptions:

• Standard two-terminal p–n junction diode.
• Forward conduction direction is anode → cathode.
• Package conventions: cathode generally marked with a band or stripe.

Concept / Approach:The anode is the positive terminal for forward bias; the cathode is the negative terminal in that condition. Current (conventional) flows from anode to cathode when forward biased. Most axial diodes mark the cathode with a stripe; on SMD packages, a bar or line indicates the cathode end. Therefore, the statement that “the positive lead is the cathode” reverses the correct naming.

Step-by-Step Solution:

Verification / Alternative check:Use a DMM in diode-test mode: connect red lead to one end and black to the other. If a sensible forward drop appears (e.g., 0.6–0.8 V for silicon), the red lead is on the anode and the black on the cathode. Reversing leads should show open (OL).

Why Other Options Are Wrong:Limiting correctness to LEDs or specific materials is misleading; naming conventions are consistent across standard diodes. Application type (e.g., reverse clamps) does not change the terminal names.

Common Pitfalls:Confusing current arrow symbols in schematics; remember the diode arrow appears only in transistor symbols (BJT) or in diodes with arrows (e.g., zener symbols lack arrows). Always trust package stripe = cathode.

Final Answer:Incorrect