The BCW66G from Nexperia is a Bipolar Junction Transistor with Emitter Base Voltage 5 V, Base Emitter Saturation Voltage 1.25 V, Emitter Cut off Current 20 nA, Collector Base Voltage 50 V, Collector Cut off Current 0.02 to 5 uA. Tags: Surface Mount, NPN Transistor. More details for BCW66G can be seen below.