What type of dimmer is classified as forward phase?

The classification of a dimmer as "forward phase" refers to the method it uses to control the power to a load, typically lighting fixtures. Forward phase dimmers work by delaying the rise of the AC voltage waveform to control the power delivered to the load.

The SCR/Triac type of dimmer functions based on this principle. It essentially turns on the current at a point after the waveform begins, allowing a portion of the wave to be "chopped" off at the start. This effectively reduces the amount of energy delivered to the light source, thus dimming it. The SCR (Silicon Controlled Rectifier) or Triac (Triode for Alternating Current) components in the dimmer are crucial for this function because they modify the AC signal in such a way that the load receives only part of the wave.

In contrast, options like IGBT (Insulated Gate Bipolar Transistor), switching dimmers, and Pulse Width Modulation (PWM) operate on different principles. IGBTs are used in different types of control mechanisms and are not typically categorized as forward phase. Switching dimmers operate by completely turning the load on or off rather than modifying the AC waveform. PWM, commonly used in LED dimming, adjusts the