Popular transistors.

BC237 transistor.
Pinout. Datasheet.

Type Designator: BC237.
Package: TO-92, 1-collector, 2-base, 3-emitter.
Material of transistor: Si
Polarity: NPN
Total Devise power dissipation |PD|: 0.5W(at ambient temperature + 25 )
Collector-base breakdown voltage |VCBO|: 50V
Collector-emitter breakdown voltage |VCEO|: 45V
Emitter-base breakdown voltage |VEBO|: 6V
Maximum collector current |Ic max|: 0.1A
Maximum junction temperature |Tj|: +150 C
Transition frequency (ft) : 200MHz(typ.)
Emitter-Base Capacitance |Cebo|:8pF
Collector-Base Capacitance|Ccbo|:4,5pF(max.)
Collector-emitter saturation voltage|VCE|:0,2V(IC=100mA,IB= 5mA)
Base-emitter saturation voltage|VBE|:0,6V(IC=100mA,IB= 5mA)
Forward current transfer ratio |hFE| : 120-800(IC=2mA,VCE=5V), 120-220(BC237A), 120-460(BC237B), 380-800(BC237C).
Noise Figure, (NF): 10dB