L2X8E3

Thyristors - TRIACs

A TRIAC (Triode for Alternating Current) is a three-terminal electronic switch that conducts current in either direction, making it ideal for alternating current applications. It is, broadly speaking, a form of thyristor, and was first developed in the 1950s byGeneral Electric for use in switching applications. The TRIAC is widely used in many commercial and industrial control and power conversion applications. For example, TRIACs are used in light dimmers, household appliances, and motor speed control.

2X8E3 Application Field and Working Principle

The 2X8E3 is a 200V 4A TRIAC, designed for high power switching applications. It is commonly used in AC load switching and control, such as in motor speed controllers, ovens, lighting, power supplies and other similar circuits. Typical applications include fans and other equipment that need to be variably switched on and off.

The 2X8E3 is a sensitive gate, three-terminal alternating current switch. It comprises two SCRs (Silicon Controlled Rectifiers) connected in inverse parallel, with each SCR connected to alternate phase lines. This configuration provides bidirectional, high-power switching capability.

TRIACs work by making use of a common anode and a pair of anode and cathode connected to the gate terminal. When a current is applied to the gate terminal, it causes a voltage drop near the junction between the anode and cathode terminals, creating charge carriers to pass current. This current in turn causes a channel to be formed between the anode and cathode terminals, turning on the TRIAC and allowing a current to flow in either direction through both SCRs.

The gate terminal is usually connected to a power source in order to provide a control signal. As the voltage on the gate terminal rises, the TRIAC triggers earlier, allowing current to flow sooner and over a longer period of time than if the TRIAC were not triggered. This enables variable control of current flow, in both amplitude and duration, allowing the TRIAC to be used in motor speed control and other variable power switching applications.

TRIACs also feature an internal diodes which allow the TRIAC to block voltage outside the specified voltage limits, making it ideal for AC applications.