A DIAC is a solid-state switch that conducts electricity above a certain breakover voltage limit and is used to switch AC voltage. When a DIAC's breakover voltage is achieved, the voltage across the diode drops and causes an increase in electric current running through the diode.
The DIAC remains charged with electric current until it drops below a certain level called the holding current. When its charge level falls below the specified holding current, the diode transitions back into a non-conducting state. An average DIAC is set with a breakover voltage of approximately 30 volts and is constructed using a three-layer structure design.