The 2N1597 from Comset Semiconductors is a Silicon Controlled Rectifier with Breakover Voltage 200 V, Breakover Current 15 A, Gate Trigger Voltage 0.2 to 3.0 V, Gate Trigger Current 2.0 to 10 mA, Temperature Operating Range -20 to 100 Degree C. Tags: Through Hole. More details for 2N1597 can be seen below.