So, you’ve finally decided it was time. Time to save power and money. You’ve turned to dimming! While dimmers lower the light intensity by controlling the power output of the lamp, there are many options out there from which you can choose from. Some are suitable for LED, some for other types of bulbs, etc.

When it comes to residential lighting, we can often see what we call “phase-cut dimming”. There are two types to phase dimming: Forward phase and Reverse phase. But, before we actually get into it, let’s get down to the basics: what is phase-cut dimming?

To make it short, phase cute dimmers work by cutting the signal from the line input power. This will bring the load to experience a lower voltage, resulting in a lower light output.

So now, what’s the difference between forward and reverse phase, you may ask? Well, let’s see:



FORWARD PHASE DIMMING

Also known as Leading-edge dimming, it cuts each half cycle of the power signal wave (see picture below). The power is off during the initial part of each half cycle and then turns on. This type of dimmer is part of the older/traditional dimmers that we know of. In many cases, these are very hard to pair with LED lights du to their high wattage range. Some LED drivers are compatible with this kind of dimming, but you need to check first.

They are usually less expensive and less complex to work with since no re-wiring is needed. Works great with:

- Incandescent

- Halogen

- CFL

- MLV

- Fluorescent

- LED (in some cases)



REVERSE PHASE DIMMING

Also called Trailing-edge dimming, the reverse phase control works very similarly to forward phase dimming by cutting each half cycle of the power wave. But this time, the power is ON during the initial part of the half cycle and then turns off in the middle of the cycle.

They work great with LED light as well as ELV systems. Their price is generally higher due to the many features it offers, such as smooth control, less noise and multi-dimming functionalities, bringing installations to last longer.

Works great with:

- LED

- CFL

- Halogen

- Incandescent

- ELV



So, in the end, the choice of dimming control you will make is pretty important and will matter in the end. Always verify your driver’s and fixture’s compatibility. If you are still hesitant about which phase dimming type is best for your future projects, feel free to contact us!



For any questions or comments, please contact us. To find out more, here is an article on how to pick a driver.