The LED Schematic Symbol
A diode triangle plus two small arrows shows light leaving the part.
Reading the symbol
The LED symbol is the ordinary diode symbol with two small arrows added. The triangle points in the direction conventional current flows, from the anode on the flat side to the cathode at the tip. The bar the triangle points at marks the cathode.
The arrows matter
Two short arrows pointing away from the diode mean it gives off light. If the arrows point toward the diode, the part is a photodiode, which senses light instead of making it. Mixing these up is a common beginner mistake.
Labels you will see
- D1, D2... or LED1, LED2... are reference designators that identify each LED on a diagram.
- Values such as red or 5 mm may sit beside the symbol.
- An RGB LED is drawn as three LED symbols sharing one common terminal.
Drawing it yourself
Draw a triangle, add a short bar across its tip, join a wire to each side and finish with two small arrows pointing away from the top. Keep the anode towards the positive side of your circuit so the diagram reads naturally from supply to ground.
Matching symbol to part
The schematic has no leg lengths, so use the symbol to decide direction, then identify the real anode and cathode on the component before soldering or plugging it in.
Try it yourself
Sketch the circuit on paper first, calculate the values, then build it on a solderless breadboard using a low-voltage supply. Measure with a multimeter before you make anything permanent.