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A diode symbol with two arrows pointing away, marking a light-emitting diode.
Also known as: Light emitting diode symbol, LED schematic symbol, Diode with arrows
The LED symbol is the diode symbol with two small arrows drawn pointing away from it, meaning light leaving the component. The same arrows pointing inward mean the opposite component — a photodiode, which detects light rather than emitting it.
Marks a light-emitting diode: a diode that emits light when current passes through it in the forward direction.
Contexts: Electrical equipment
Adds two small parallel arrows pointing away from the diode body, a general schematic convention meaning radiation leaving a component.
Contexts: Electrical equipment
Is distinguished from the photodiode only by the direction of those arrows: pointing away means light is emitted, pointing toward means light is detected. The two components are functional opposites and the arrowheads are the only difference on the page.
A practical reading trap worth stating: at small scale on a dense schematic the arrow direction is easy to miss.
Contexts: Electrical equipment
Is an ordinary diode symbol with two arrows leaving it. The arrows point away because the light comes out; the same arrows pointing in make a photodiode, which does the opposite job. Everything else about the symbol — the triangle, the cathode bar, the band on the real part — behaves exactly as it does for any diode.
Contexts: Technical drawing, Electrical equipment
Related forms that are not treated as separate canonical symbols — see our variant rules.
Infrared emitter
The same symbol, sometimes drawn with wavy rather than straight arrows to indicate radiation outside the visible band. The distinction is made in the annotation more often than in the drawing.
A solid triangle meeting a short bar at its tip, with two small parallel arrows drawn diagonally alongside, both pointing away from the triangle.
Identical but for the two added arrows, which are easy to overlook on a dense diagram.