TRIACS (triodes for alternating current) are silicone semiconductor components with three terminals or feet that allow the current to pass in both directions when activated. TRIACs are widely used for the switching and control of power of AC systems. TRIACs are particularly useful in applications such as dimmers because they allow the use of each semi-cycle AC wave. The solid-state device can be utilised in a circuit as a simple on/off device in a wide range of electronic applications. Some of the most common areas include temperature control, liquid level control, brightness variators for domestic lighting, small motor control, and speed control for electric fans.