Popular transistors.

BC548 transistor.
Pinout. Datasheet.

Type Designator: BC548.
Package: TO-92, 1-collector, 2-base, 3-emitter.
Material of transistor: Si
Polarity: NPN
Total Devise power dissipation |PD|: 0.625W(at ambient temperature ≤ + 25 )
Collector-base breakdown voltage |VCBO|: 30V
Collector-emitter breakdown voltage |VCEO|: 30V
Emitter-base breakdown voltage |VEBO|: 6V
Maximum collector current |Ic max|: 0.1A
Maximum junction temperature |Tj|: +150 C
Transition frequency (ft) : 300MHz
Input Capacitance |Cib|:10pF
Output Capacitance |Cob|:1,7pF
Collector-emitter saturation voltage|VCE|:
Base-emitter saturation voltage|VBE|:
Forward current transfer ratio |hFE|:
110-900,(IC=2mA,VCE=5V), 200-450(BC548B) ,
Turn-on time|t on |:35ns
Turn-off time |t off |:300ns
Noise Figure, (NF): 2-10dB

Example of application.

BC546, BC547, BC548 transistors are very popular in the world.
They are used in various electronic devices for amplification and switching purposes, in a wide range of frequencies.
You can use them:
1. In the audio-frequency amplifiers.
For example: mini-amplifier with push - pull output.

BC547,BC557 in amplifier with push-pull output

Resistors: R1-1 MOm, R2-56 KOm, R3-1 KOm, R4-240 Om,
R5-220 KOm.
Capacitors: C1-1 µF, C2-5 µF, C3-47 nF, C4,C5-100 µF*12V.
Transistors: Q1, Q4 - BC546, BC547, BC548; Q2, Q3 - BC557.

2.Radio-frequency amplifiers(in transistor radio AM).
BC547,BC557 in transistor radio AM

Resistors: R1, R4 - 220* KOm, R2 - 75* KOm,
R3, R5 - 10 KOm, R6 - 56 KOm, R7 - 12 KOm, R8 - 870 Om.
Capacitors:variable C1 - 20-415pF, C2 - 10 nF, C3 - 100nF,
C4 - 5 µF*6V.
Transistors: Q1, Q2, Q3, Q4 - BC546, BC547, BC548;
Q5 - BC557.
Loopstick antenna L1 - 60 turns wire 0,25mm
wrapped around 10mm ferrite rod;

3. In Radio-frequency oscillators(in transistor radio FM.)
BC547,BC557 in transistor radio FM

Variable resistor - 10 KOm.
Capacitors:variable C1 - 5-35pF, C2 - 5-14 pF, C3 - 0,1 µF,
C4 - 10 pF.
Coils: L1-8,5 and L2-2,5 turns diam 6mm;
L3, L4, L5 - 8 turns diam 8mm.
Transistor - BC546, BC547, BC548.

Ratings and characteristics curves.

BC546, BC547, BC548.
Collector-base capacitance,
Emitter-base capacitance
versus reverse bias voltage(Tamb=25 C).

BC546, BC547, BC548.Ratings and characteristics curves.Collector-base capacitance,Emitter-base capacitance versus reverse bias voltage.

BC546, BC547, BC548.
Gain-bandwidth product
versus collector current(Tamb=25 C,VCE=10V).

BC546, BC547, BC548.Ratings and characteristics curves.Gain-bandwidth product versus collector current.

BC546, BC547, BC548.
Relative h-parameters
versus collector current(Tamb=25 C,VCE=5V).

BC546, BC547, BC548.Ratings and characteristics curves.Relative h-parameters versus collector current.

BC546, BC547, BC548.
Base-Emitter Saturation Voltage(VBE)
Collector-Emitter Saturation Voltage (VCE).

BC546, BC547, BC548..Base-Emitter Saturation Voltage. Collector-Emitter Saturation Voltage.

BC546, BC547, BC548..Transfer Characteristic.

BC546, BC547, BC548..Transfer Characteristic.

BC546, BC547, BC548.Static Characteristic.

BC546, BC547, BC548..Static Characteristic.