To adjust the lighting to suit the atmosphere of the room, it is often a good idea to purchase a dimmer. This allows you to make the lighting brighter when you need better visibility, or turn it down when the room calls for a cozy and atmospheric setting. With a dimmer, you can create different atmospheres in a single room.

What is a dimmer?

A dimmer is a type of switch that allows you to regulate the power supply or voltage to an electrical device. The best-known type of dimmer is a light dimmer, which allows you to make lamps brighter or dimmer. A dimmer has a minimum and maximum power rating. If you try to dim a lamp with a power rating below this minimum limit, the lamp will start to flicker. If you try to dim a lamp with a power rating higher than the dimmer’s maximum power rating, there is a good chance that the dimmer will break. Always check this carefully when installing a dimmer.

What type of dimmer do I need for LED lighting?

There are roughly two different types of dimmers: dimmers that work using leading-edge phase control and dimmers that work using trailing-edge phase control. Leading-edge phase control means that at the beginning of each fluctuation (or phase), the alternating voltage is briefly interrupted. The appearance of leading-edge phase control is shown in the image below.

There are also dimmers that use trailing-edge phase control. Trailing-edge phase control means that the alternating voltage is briefly interrupted at the end of each fluctuation/phase. Dimmers with trailing-edge phase control are almost always used for dimmable LED lamps. The appearance of trailing-edge phase control is shown schematically below.

Nowadays, there are also universal dimmers that support both leading-edge and trailing-edge phase control. This way, you can be sure that your lamp is dimmable with this dimmer! When installing a dimmer, make sure that the LED lamps or spotlights you have purchased are also dimmable. It is not recommended to connect a dimmer to a non-dimmable LED lamp.

How many LED spotlights can be connected to one dimmer?

How many LED spotlights can be connected to one dimmer depends on the dimmer’s minimum and maximum power rating, as well as the power rating of the LED spotlights. A dimmer that only has to dim 6 LED spotlights has a different power rating from a dimmer that has to dim 16 LED spotlights. As a rule of thumb, remember that the connected lamps should have a total power rating around 10% lower than the dimmer’s maximum power rating. For example, suppose you have a 2–100-watt dimmer and LED spotlights rated at 4W each. It is recommended that you connect a maximum load of 90W to the dimmer. Therefore, 90/4 = 22 to 23 4W LED lamps can be connected to this dimmer.