Dimmer Switches

A dimmer switch replaces a standard 1-gang switch and allows you to vary the brightness of compatible lights.

How Dimmers Work

A dimmer chops the AC waveform — it switches the load off for a portion of each cycle. This reduces the average power delivered to the lamp.

Full brightness (100%)Dimmed (50%)

Compatibility

Not all lamps are dimmable. LED lamps must be marked "dimmable" — a non-dimmable LED on a dimmer will flicker, buzz, or fail early.

The dimmer switch must also be rated for the total wattage of the lamps:

  • Old dimmers were rated for halogen/incandescent (e.g. 250W)
  • LED dimmers are often rated at much lower wattages

Wiring

A dimmer wires identically to a 1-gang switch:

  • Switch live in → COM terminal
  • Switch return → L terminal

Some dimmers have a separate earth terminal — always connect the earth.

Minimum Load

Many LED dimmers require a minimum load (e.g. 10W). A single low-power LED on a dimmer designed for multiple lamps may cause flickering. Check the minimum load in the dimmer's datasheet.

Neutral-Required Dimmers

Some smart dimmers require a neutral at the switch. In standard loop-in wiring there is no neutral at the switch — you would need a different smart switch design or to rewire with a neutral conductor.