Diacs Trigger Diode

A diac is a two-terminal, bidirectional, semiconductor device that is used as a trigger diode in AC switching circuits. A diac is a type of diode that is specifically designed to break down and conduct current at a specific, fixed voltage. When a diac is used as a trigger diode, it is connected in parallel with a load, such as a triac or thyristor, and a small AC voltage is applied to the diac's gate terminal. When the AC voltage exceeds the diac's breakdown voltage, the diac conducts current and triggers the triac or thyristor, allowing current to flow through the load. Diacs are commonly used in AC switching circuits, such as those found in dimmers and motor control systems, to control the flow of current.