Bipolar Junction Transistor

A Transistor that is controlled with Current.

Bipolar Junction Transistor-1762474692345.svg > invert

Properties

Breakdown

  • base-emitter breakdown occurs when Emitter voltage is much higher than base voltage, use protection Diode

Bipolar Junction Transistor-1760709670456.png > invert

BJT Rules

  • polarity: must be greater than
  • junctions:
    • base-emitter is a forward biased diode, enabling a larger current through collector and emitter
    • base-collector is a reverse biased diode
  • max ratings: , , and have a max rating
  • when above are obeyed,

Design Considerations

  • choose a larger base current than necessary since is low at low
  • use suppression diode when switching an inductive load