The BTC4621K3 from Cystech Electronics is a Bipolar Junction Transistor with Emitter Base Voltage 6 V, Base Emitter Saturation Voltage 1 V, Emitter Cut off Current 0.1 µA, Collector Base Voltage 350 V, Collector Cut off Current 0.1 µA. Tags: Through Hole, NPN Transistor. More details for BTC4621K3 can be seen below.