Electronic Circuits/Transistor Active Mode Equations

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

 * 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.

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