What is ‘leading edge’?

Leading Edge Dimming (TRIAC dimming) utilizes a current that is turned off as the AC waveform begins, right after it crosses zero. Leading Edge Dimming is typically used with incandescent bulbs, and produces a rush of voltage every half cycle, resulting in a rush of current to the light source.

What is ‘trailing edge’?

Trailing Edge Dimming (electronic dimming) utilizes a current that is turned off as the AC waveform ends, right before it crosses zero. This type of dimming is typically used with electronic drivers, and does not result in a rush of voltage (and in turn, a rush of current) to the light source.

The differences between a three-point leading edge dimmer and a trailing edge dimmer are listed below:

Leading edge：

1.Cheaper and simpler

2.Provide high minimum load

3.Common in use but not in LED lighting circuits

Trailing edge:

1.More expensive and sophisticated

2.Provide low minimum load

3.Commonly used in low powered lighting circuits