LED
A Light-Emitting Diode that emits light when forward current flows through it. Has a characteristic forward voltage drop and a maximum current rating. Widely used as indicators, status lights, and displays.
Properties
| Property | Description | Default | Range |
|---|---|---|---|
| Forward voltage | Voltage drop across the LED when conducting (V) | 2.0 V | 1.5 V – 4.0 V |
| Max current | Maximum continuous forward current before failure (mA) | 20 mA | 1 mA – 350 mA |
| Color | Emitted light color (affects forward voltage model) | Red | Red / Green / Blue / Yellow / White / IR |
| Brightness model | How brightness scales with current (Linear / Logarithmic) | Logarithmic |
Simulation behavior
When forward voltage across the LED reaches the forward voltage threshold, the LED begins conducting and lights up on the canvas. Brightness increases with current up to max current.
If current exceeds max current, the LED fails open and stops emitting light. The failure is logged in the simulation log.
Reverse voltage is blocked (like a diode) up to a reverse breakdown of approximately 5 V — exceeding this destroys the LED.
Tips
- Always add a series current-limiting resistor: R = (Vsupply – Vforward) / Idesired. For a 5 V supply, a red LED (Vf = 2 V) at 10 mA needs a 300 Ω resistor.
- Different colors have different forward voltages: Red ≈ 1.8–2.2 V, Green ≈ 2.0–2.5 V, Blue/White ≈ 3.0–3.5 V. Match the property to your chosen color.
- Use Logarithmic brightness model for a more realistic visual — the human eye perceives brightness logarithmically, so the LED appears to ramp up quickly and then plateau.