A Triac is a type of semiconductor device that can control electrical power. It is commonly used in applications like light dimmers, motor speed controls, and heating systems. The Triac can conduct current in both directions, making it versatile for alternating current (AC) circuits. When a small voltage is applied to its gate terminal, the Triac turns on and allows current to flow. Once activated, it remains on until the current drops below a certain level. This ability to switch on and off makes the Triac an essential component in various electronic devices and systems.