Popular transistors.

2N3904 transistor.
Pinout. Datasheet.

Type Designator: 2N3904.
Package: TO-92, 1-emitter, 2-base, 3-collector.
Material of transistor: Si
Polarity: NPN
Total Devise power dissipation |PD|: 0,5 W(at ambient temperature ≤ + 25 )
Collector-base breakdown voltage |VCBO|: 60V
Collector-emitter breakdown voltage |VCEO|: 40V
Emitter-base breakdown voltage |VEBO|: 6V
Maximum collector current-continuous |Ic max|: 0,2A
Maximum junction temperature |Tj|: 150 C
Transition frequency (ft) : 300MHz
Emitter Input Capacitance |Cib|:8pF
Collector Output Capacitance |Cob|:4pF
Collector-emitter saturation voltage|VCE|:0,2V(IC=10mA,IB=1mA),
0,2V(IC=50mA,IB=5mA)
Base-emitter saturation voltage|VBE|:0,85V(IC=10mA,IB=1mA),
0,95V(IC=50mA,IB=5mA)
Forward current transfer ratio |hFE| : 100-300(IC=10mA,VCE=1V)
Turn-on time|t on |:70ns
Turn-off time |t off |:250ns
Noise Figure, (NF): 5dB