Diode Symbol: Anode, Cathode & Current Direction

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• Read the diode symbol, tell the anode from the cathode, and recognize Zener, Schottky, LED and photodiode variants without inferring ratings from the icon alone.
• Original symbol illustrations, a reading check and feedback for learning.

What does this symbol mean?

A diode is drawn as a triangle pointing at a bar. The triangle side is the anode (A) and the bar side is the cathode (K). In the conventional-current model, forward current flows from anode to cathode when the diode is forward-biased.

The symbol shows orientation, not ratings or the state of a real circuit. Zener, Schottky, LED, photodiode and bridge-rectifier variants add their own marks; the legend, reference designator (often D or CR) and datasheet identify the actual part.

See the symbol

How to read it in context

1. Find the reference designator (often D or CR) and any variant mark such as bent bar ends or arrows.
2. Identify which end is the anode and which is the cathode from the triangle and bar, not from wire colour or position on the page.
3. Trace the connected nodes and read the schedule or datasheet before assuming function, polarity or ratings.

Common look-alikes and mistakes

• The triangle points toward the cathode bar and shows the forward conventional-current direction; it is not an arrow telling you to route a conductor that way.
• A bar at one end does not by itself prove that terminal is at a lower potential in every circuit; the surrounding circuit and operating state decide.
• LED and photodiode variants both use arrows, but the arrow direction and the surrounding labels give them different meanings.
• The diode symbol does not make a circuit safe to probe or test; measurement boundaries come from the applicable procedure.

Try the symbol-reading check

Standards, sources and related symbols

These are independently drawn teaching diagrams. They help you read a drawing, but the project legend, applicable standard and equipment documentation control the actual meaning. Editorial source check: 29 October 2026.

• IEC 60617 — graphical symbols for diagrams
• IEC 60617 — graphical symbols for diagrams
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