Popular transistors.

BC848B transistor.
Pinout. Datasheet.

Marking:1K with an additional letter, or dash sign, denoting the manufacturer.For example - 1Kp and1K-(made in Hong Kong), 1Kt(made in Malaysia),1KW(made in China).
Package: SOT-23, 1-collector, 2-emitter, 3-base.
Material of transistor: Si
Polarity: NPN
Total Devise power dissipation |PD|: 0.225 W(at ambient temperature ≤ + 25 )
Collector-base breakdown voltage |VCBO|: 30V
Collector-emitter breakdown voltage |VCEO|: 35V
Emitter-base breakdown voltage |VEBO|: 5V
Maximum collector current |Ic max|: 0.1A
Maximum junction temperature |Tj|: +150 C
Transition frequency (ft) : 100MHz(min)
Collector-outpute Capacitance|Cob|:4,5pF(max.)
Collector-emitter saturation voltage|VCE|:600mV(IC=100mA,IB= 5mA)
Base-emitter saturation voltage|VBE|:900mV(IC=100mA,IB=5mA)
Forward current transfer ratio |hFE| : 200-450,(IC= 2mA,VCE=5V),

BC848B Datasheet (PDF)

Table for identifying the type of SMD devices.