Reading from Chapter 4: Difference between revisions

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<math>\beta=i_C/i_D</math>
<math>\beta=i_C/i_D</math>

*Operation in the active region:
*The base-emitter junction is forward biased.
*The base-collector junction is reverse biased.
*As amplifiers, BJTs operate in the active region.
*As switches, BJTs operate in saturation and cutoff.

Revision as of 22:50, 4 February 2010

Bipolar Junction Transistor

  • An npn BJT has two layers of n-type material, known as the collector and emitter, and in between a layer of p-type material, known as the base.
  • In order for a BJT to have a good performance, the base current needs to be small compared to the collector current.

  • Operation in the active region:
*The base-emitter junction is forward biased.
*The base-collector junction is reverse biased.
  • As amplifiers, BJTs operate in the active region.
  • As switches, BJTs operate in saturation and cutoff.