The BC547B from Diotec Semiconductor is a Bipolar Junction Transistor with Emitter Base Voltage 5 V, Base Emitter Saturation Voltage 700 to 900 mV, Collector Base Voltage 50 V, Collector Cut off Current 4 µA, Collector Emitter Voltage 45 V. Tags: Through Hole, NPN Transistor. More details for BC547B can be seen below.