Faiyaz said:
Thank you ROn H. For once there is some one who agrees with me. I actually lost a job because of making such a statement.
You may already know all this.
The base-emitter diode current (Ib) is
Ib = Is*( e^(q*Vbe/(n*k*T)) - 1 ),
where
Is is the diode saturation current (reverse bias leakage),
Vbe=base-emitter voltage,
e=2.71828...., the Naperian logarithm base,
q=1.602*10^-19 coulombs, the charge on an electron,
k=1.3807*10^-23 joules per kelvin, Boltzmann's constant,
1<n<2, the diode ideality factor (n=1 nominally, but varies),
T=temperature, degrees kelvin.
nkT/q is approximately 26mv at room temperature, so
Ib=Is*(e^(Vbe/.026)-1), and if Vbe>>.026,
Ib=Is*e^(Vbe/.026)
Since collector current Ic =beta*Ib,
Ic=beta*Is*e^(Vbe/.026) at room temperature, proving that the BJT is a voltage-controlled device.
Having said that, I still think it is easier to think of it as a current-controlled device, i.e., Ic=beta*Ib.