The BCW66F from Diotec Semiconductor is a Bipolar Junction Transistor with Emitter Base Voltage 5 V, Base Emitter Saturation Voltage 1.25 to 2 V, Emitter Cut off Current 20 nA, Collector Base Voltage 75 V, Collector Cut off Current 20 µA. Tags: Surface Mount, NPN Transistor. More details for BCW66F can be seen below.