The BC557A from SeCoS Corporation is a Bipolar Junction Transistor with Emitter Base Voltage -6 V, Base Emitter Saturation Voltage -1 V, Emitter Cut off Current -0.1 µA, Collector Base Voltage -50 V, Collector Cut off Current -0.1 µA. Tags: Through Hole, PNP Transistor. More details for BC557A can be seen below.