The BT152B-400R from WeEN Semiconductors is a Silicon Controlled Rectifier with Breakover Voltage 450 V, Breakover Current 200 A, Gate Trigger Voltage 0.4 to 1.5 V, Gate Trigger Current 0.032 A, Temperature Operating Range -40 to 150 Degree C. Tags: Surface Mount. More details for BT152B-400R can be seen below.