BC548 transistor

BC548 transistor
BC548 transistor

BC548 specification

  • It is a general-purpose NPN Transistor
  • DC Current Gain range is 110 to 800hFE
  • Collector current (IC) is 100mA
  • Collector to base Voltage (VCB) is 60V
  • Collector to emitter voltage (VCE) is 30v
  • Emitter to base voltage (VEB) is 5V
  • Junction temperature (TJ) is 150°C
  • Power dissipation at the transistor is 500mW
  • Transition frequency (FT) is 300MHz

BC548 pinout

Pin Number Pin Name Description
1 Collector Current flow through the collector
2 Base Triggers the device
3 Emitter Current flows through the emitter


BC548 pinout
BC548 pinout

BC548 package

The package used to build the BC548 transistor is TO-92, the making of TO-92 is with the mixture of epoxy and plastic.

This type of transistor package is good because it is less expensive, more compact for circuit making. The TO-92 transistor package makes the component low weight.

BC548 Description

The BC548 transistor is a general-purpose device, it is a low power, low current electronic device, which had more applications at our common appliances.

The peak current gain of the BC548 transistor is 110 to 800hFE, the gain value is very important at applications like an amplifier and the BC548 is apt for the amplifier circuits.

The maximum collector current at BC548 transistor is noted as 100mA, the current value indicates the maximum load allowed for the device, most of the applications using transistor will refer to this value.

The maximum power dissipation at the BC548 is 500mW, the total dissipation of the transistor indicates the capacity of power dissipation at the BC548.

The transition frequency on the BC548 transistor is 300MHZ, it is an important factor in switching applications.

The junction temperature of the BC548 is 150°C.

BC548 transistor datasheet 

BC548 transistor datasheet 
BC548 transistor datasheet

If you need the datasheet in pdf please click this link

BC548 Equivalent

The BC548 is an NPN BJT transistor, the equivalent transistor listed here has almost similar specifications as BC548.

The equivalent transistors are BC547, BC549, 2n2222, and BC550, each transistor in this list had similar characteristics as BC548. They all are the replaceable transistor for BC548.

BC548 vs BC547 vs BC549 vs 2n3904

The table below gives us an idea about each transistor’s electrical specifications, in this table, we include BC548 vs BC547 and BC549 vs 2n3904.

An overall comparison of characteristics of a transistor is really helpful for the replacement purpose. 

Characteristics BC548 BC547 BC549 2n3904
Collector to base voltage (VCB)30V50V30V60V
Collector to emitter voltage (VCE) 30V45V30V40V
Emitter to base voltage (VEB)5V5V5V6V
Collector current (IC)100mA100mA100mA200mA
Power dissipation 500mW500mW500mW625mW
Junction temperature (TJ)150°C150°C150°C150°C
Transition frequency (FT)300MHZ300MHZ300MHZ300MHZ
Noise (N)10dB10dB4dB5dB
Gain (hFE)110 to 800hFE110to 800hFE110to 800hFE30 to 300Hfe
Package TO-92TO-92TO-92TO-92

BC548 applications

  • Sensor circuits
  • Driving load up to 500Ma
  • Audio amplifier circuits
  • Push-pull amplifier
  • Preamp circuit
  • Signal amplifier
  • Relay driver circuit

BC548 amplifier circuit diagram

BC548 amplifier circuit diagram
BC548 amplifier circuit diagram

The figure shows a simple amplifier circuit using BC548 transistor, minimum components are used at this circuit to make an amplifier.

When the audio signal reaches the input of the circuit, the input capacitor bypasses the DC and passes over to the bc548 transistor.

The BC548 transistor amplifies the signal and passes it to the output.  

BC548 relay circuit

BC548 relay circuit
BC548 relay circuit

The figure shows the relay driver circuit using BC548 transistor, for this circuit we need a few components to control the relay.

The relay driver circuit consists of four components, bc548 transistor, resistor, relay, and a flyback diode.

Combined operations of the diode and BC548 transistor make the relay much easier to handle high voltages.

When the relay works between DC and AC signals, a higher amount of current will flow through it, but the relay coil is not good at handling it.

Here the diode and BC548 transistor make an easier path for the high-value currents to flow out to the ground.

BC548 price

The BC548 transistor is a low voltage, low current device, this is why BC548 had more common applications at general-purpose circuits.

The price for BC548 is 10rupees for 5piece or 0.13USD dollars.

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