Motorola MBS4991 Diode Thyristor

According to the manufacturer this Motorola MBS4991 Diode Thyristor is designed for full-wave triggering in Triac phase control circuits, half-wave SCR triggering application and as voltage level detectors. Supplied in an inexpensive plastic TO-226AA package for high-volume requirements, this low-cost plastic package is readily adaptable for use in automatic insertion equipment.