BC558 General Purpose PNP Transistor
The BC548 is a general purpose epitaxial silicon PNP bipolar junction transistor
The pinout for the TO-92 package used for the BC546 to BC560 has pin 1 (the leftmost pin in the diagram above, i.e. when the flat face of the package faces the viewer with leads at the bottom) attached to the collector, pin 2 connected to the base, and pin 3 connected to the emitter. Note that not all transistors with TO-92 cases follow this pinout arrangement.