The BC859B from Diotec Semiconductor is a Bipolar Junction Transistor with Emitter Base Voltage 5 V, Base Emitter Saturation Voltage 700 to 900 mV, Emitter Cut off Current 100 nA, Collector Base Voltage 30 V, Collector Cut off Current 0.1 to 4 µA. Tags: Surface Mount, PNP Transistor. More details for BC859B can be seen below.