Popular transistors.

BC550 transistor.
Pinout. Datasheet.

Type Designator: BC550.
Package: TO-92, 1-collector, 2-base, 3-emitter.
Material of transistor: Si
Polarity: NPN
Total Devise power dissipation |PD|: 0.5 W(at ambient temperature ≤ + 25 )
Collector-base breakdown voltage |VCBO|: 50V
Collector-emitter breakdown voltage |VCEO|: 45V
Emitter-base breakdown voltage |VEBO|: 5V
Maximum collector current |Ic max|: 0.1A
Maximum junction temperature |Tj|: +150 C
Transition frequency (ft) : 100MHz(min.)
Emitter Capacitance |Ce|:11pF
Collector Capacitance |Cc|:1,5pF
Collector-emitter saturation voltage|VCE|:0,09V(IC=10mA,IB=0,5mA),
0,2 V(IC=100mA,IB=5mA)
Base-emitter saturation voltage|VBE|:0,7 V(IC=10mA,IB=0,5mA),
0,9 V(IC=100mA,IB=5mA)
Forward current transfer ratio |hFE| : 420-800,(IC=2mA,VCE=5V), 270(typ.)(BC550C)
Noise Figure, (NF): 4dB