Dimming Methods

The importance of dimming

Dimming can be used to enhance the ambiance of a space, increase visual acuity, and customize lighting based on the task. A single fixture can be dimmed to many levels, allowing one fixture to be used for multiple applications while minimizing the number of products to specify for a location.

Dimming can be used along with occupancy sensors and daylight harvesting to save energy while still meeting the lighting needs of a space.

In addition, LED is the only lighting technology that gets more efficient as it is dimmed. Dimming even increases the lifespan of LED products.

Types of driver controls

There are different kinds of dimming controls. One way-controls (phase dimming, PWM, 0-10V) are simpler, but two-way controls (DMX and DALI) allow for greater functionality.

Phase dimming

The majority of installed dimmers are phase dimmers. Phase dimming involves clipping part of the sine wave to deliver less power to the light source, resulting in a dimmed light. There are two types phase dimming.

Forward phase (leading edge) dimming was commonly used for incandescent and halogen lighting. The front of the wave is clipped. This type of dimming is suitable for inductive and restive loads such as incandescent bulbs and magnetic ballasts.


Reverse phase (trailing edge) dimming clips the back of the sine wave. This is suitable for capacitive loads such as LEDs. Forward phase is not suitable for these loads since the capacitors do not have time to charge, resulting in flickering light.


PWM