The STMicroelectronics BTA12-600CWRG is a TRIAC ALTERNISTOR, a type of thyristor, with a maximum voltage rating of 600V and a TO220AB package. It is a bidirectional, three-terminal, solid-state semiconductor device that can be used to control the flow of current in both directions. It is designed for use in AC switching applications, such as motor control, lighting control, and power control. It features a low on-state voltage drop, low gate current, and high surge current capability. It is also RoHS compliant and has a high temperature rating of 175°C. Applications include AC motor control, lighting control, power control, and other AC switching applications.