Dimmers are devices connected to a variable device fixture and it is used to lower the brightness of the variable device. By changing the voltage waveform applied to that device, it is possible to lower the intensity of the device output. Although variable-voltage devices are used for various purposes, the term dimmer is specially for those intended to control light output from resistive incandescent and compact fluorescent lights (CFLs)(specially).

AC Dimmer is designed to control the alternating current voltage, which can transfer current up to 600V/16А. In most cases, Dimmer is used to turn power ON/OFF the lamps or heating elements, it can also be used in fans, pumps, air cleaners and the demonstrated Dimmer will work for all the AC appliances.

Disclaimer: The demonstrated device will not work for Light Emitting Diodes (LEDs). But due to some advancement in the technology of the LEDs, it becomes easier to find a suitable energy-efficient LED replacement to work with the dimming system.

This device is generally used for smart home system. When a user want to change the brightness of the lamp smoothly, this dimmer will be used. The lamp will slowly turns ON or OFF, creating a comfortable atmosphere for the lamp to fade evenly. Dimmer works most effective with filament lamps. It is less stable with low brightness dimmable LED lamps, but with moderate and high brightness it will perform a solid job.

The luminescent lamps (gas discharge lamps) do not support dimming as light is produced by gas discharge that occurs in an arc tube between two electrodes after ignition. Electrical conductivity in gas discharge is established by ionized filler components. The electrodes are fed into a completely sealed discharge vessel. Most discharge lamps require a control gear to spark them and limit their current due to this reason (gas discharge lamps) do not support dimming capability.

Power part of dimmer is isolated from the control part, to exclude the possibility of high current disruption to a microcontroller.