The 2N1850AHR from Digitron Semiconductors is a Silicon Controlled Rectifier with Breakover Voltage 500 V, Breakover Current 150 to 157 A, Gate Trigger Voltage 3 V, Gate Trigger Current 80 mA, Temperature Operating Range -40 to 100 Degree C. Tags: Screw Mount. More details for 2N1850AHR can be seen below.