Popular transistors.

2N5551 transistor.
Pinout. Datasheet.

Marking: 2N5551.
Package: TO-92, 1-emitter, 2-base, 3-collector.
Material of transistor: Si
Polarity: NPN
Total Devise power dissipation |PD|: 0,65W
Collector-base breakdown voltage |VCBO|: 180V
Collector-emitter breakdown voltage |VCEO|: 160V
Emitter-base breakdown voltage |VEBO|: 6V
Maximum collector current-continuous |Ic max|: 0,6A
Maximum junction temperature |Tj|: 150 °C
Transition frequency (ft) : 100MHz(min)
Emitter Capacitance |Ce|:20pF
Collector Capacitance |Cc|:6pF
Collector-emitter saturation voltage|VCE|:0,15V(IC=10mA,IB=1mA),
0,2V(IC=50mA,IB=5mA)
Base-emitter saturation voltage|VBE|:1V(IC=10mA,IB=1mA),
1V(IC=50mA,IB=5mA)
Forward current transfer ratio |hFE| : 80-250(IC=10mA,VCE=1V)
Noise Figure, (NF): 8dB