The BT151-800R 127 is a bidirectional analog thyristor from NXP (formerly Philips Semiconductors). This thyristor is a two-terminal device that contains two PN junctions and can be used as an efficient switch for controlling the flow of current. It is designed to effectively control alternating current (AC) and direct current (DC) applications with high reliability, providing excellent off-state blocking capability up to 800 volts and on-state current ranging from 3 amperes (A) up to 25A. The BT151-800R 127 is designed for use in motor control, industrial heating, lighting control, and other power switching applications. It offers fast turn-on and turn-off times, positive temperature coefficient (PTC), and a high dielectric strength.