Electronic Circuits/Transistor Active Mode Equations

From Wikiversity
Jump to navigation Jump to search

If a npn transistor is known to be in active mode the following equations will always hold true for it:

  • ic = Is*exp(Vbe/Vt)
  • ic = B*ib
  • ic = ie - ib
  • B = ic/ib
  • a = B/(B+1)
  • ie = ic + ib
  • ie = Is*exp(Vbe/Vt) + ib
  • ie = B*ib + ib
  • ie = ib(B + 1)
  • Vbe = vb - Ve
  • Vce = Vc - Ve

Terms[edit]

  • B, Beta is a manufacturing constant
  • Vt, is the thermanl voltage typically around 25mV, but one shouldnt assume so unless you have to
  • Vbe, is typically around .7v, but one shouldnt assume so unless you have to.


Derivations[edit]

Conculsions[edit]

Given Beta and one current nearly any piece of relevant information can be found.