Triac is a kind of semiconductor device widely used in power control and switching. It has applications in switch, phase control, chopper design, brightness control of lamps, speed control of fans and motors, etc. Power control system is used to control the level of AC and DC distribution. The key electronic component in the dimmer which makes dimming possible is called "dimmable triac". Therefore, all these types of dimmers are "triac led dimmer".

Forward Phase is another term for Leading Edge dimming. When you chop a sine wave, you can chop either the beginning or the end of a wave. In both cases, you can dimmer the light by reducing the output power. The more you chop, the darker the light gets. Thus, if the SCR chops the beginning of the sinusoidal wave, it is a "Forward Phase" dimming.

Hence dimmer triac led not only refers to forward phase dimming, but also including trailing Edge dimming. But forward phase is a kind of triac dimming.