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BC857 PNP Transistor

BC857 Pin Configuration

Pin No.

Pin Name




Controls the biasing of transistor, Used to turn ON or OFF the transistor



Current Drains out through emitter, normally connected to ground



Current flows in through collector, normally connected to load



  • Type: PNP
  • Low Current (max. 100mA)
  • Low Voltage (max. 65V)
  • Package Type: SOT-23
  • Transition Frequency: 150MHz
  • Noise Figure: 2dB


Technical Specifications

  • Collector-Emitter Voltage (Vce): 45V
  • Collector-Base Voltage (Vcb): 50V
  • Emitter-Base Voltage (Veb): 5V
  • Collector Current: 0.1Amps
  • Current Gain (hFe): 125 to 800
  • Operating and Storage Temperature Range: -65 to 150°C


Complementary NPN Transistors

BC846, BC847, and BC848


BC857 Equivalent Transistors

BC856, BC860, FMMTA55, FMMTA56, FMMTA92, KST55, KST56, KST92, KST93, MMBTA55, MMBTA56, MMBTA92, PBHV9040T, PBHV9115T, PMBTA56 or PMBTA92


Brief about BC857 Transistor

BC857 has a gain value of 125 to 800, this value determines the amplification capacity of the transistor. To bias the transistor we have to supply current to base pin, this current (IB) should be maximum to 200mA and voltage across the base-emitter pin should be 5V.

When this transistor is fully biased then it can allow the current to flow across the collector and emitter. BC857 comes with SOT-23 package, which has a plastic package.

BC857 can be used for general purpose switching and amplification.


How to Use?

The main working principle of a PNP transistor is when the current exists at the base of the PNP transistor, and then the transistor remains OFF. When there is no flow of current at the base of the transistor, the transistor switches ON.

 Circuit using BC857 PNP Transistor


The current is sinked into the PNP transistor and current flows from emitter to collector and this is the main difference between the NPN and PNP transistor. To switch ON a PNP transistor, you need the base voltage to be less than the emitter voltage. This is because the base terminal is made-up of an n-type semiconductor and emitter is made-up of p-type semiconductor. Connections can be made as per the given circuit diagram above.



BC857 PNP Transistor 2D-Model

Component Datasheet

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