The KTC3879-Y from SeCoS Corporation is a Bipolar Junction Transistor with Emitter Base Voltage 4 V, Base Emitter Saturation Voltage 1 V, Emitter Cut off Current 0.1 µA, Collector Base Voltage 35 V, Collector Cut off Current 0.1 µA. Tags: Surface Mount, NPN Transistor. More details for KTC3879-Y can be seen below.