PWM: dimming an LED

Goal

Breathe an LED from 0 to 255 with analogWrite().

Why it matters

PWM fakes an analog voltage by chopping the signal very fast — the basis of dimmers and motor drives.

Steps

1. 01Place the LED on a PWM pin (3, 5, 6, 9, 10 or 11).
2. 02Ramp a variable from 0 to 255 with a for loop.
3. 03Apply analogWrite(pin, value), then ramp back down.

Next tutorials

• Potentiometer → brightness

  Set LED brightness with the knob (10 bits to 8 bits).

• RGB LED: mixing colours

  Create any colour with three PWM channels.

• Smooth fade (sine curve)

  Make the fade look linear by using a non-linear curve.

• Buzzer: playing notes

  Play a scale with tone() on pin 8.