The NTE5491 from NTE Electronics is a Silicon Controlled Rectifier with Breakover Voltage 100 V, Breakover Current 150 A, Gate Trigger Voltage 0.65 to 2 V, Gate Trigger Current 0.04 A, Temperature Operating Range -65 to 125 Degree C. Tags: Stud Mount. More details for NTE5491 can be seen below.