I am a student. Our teacher gave us a problem that can be done by Kirchhoff's laws. The problem is that in the second case we have to calculate β → ∞, the teachers told us to calculate β using a limit, but I don't know how to do this if there is no function to take the limit to ∞. This is the only information the problem gives. The (O1) and (O2) squares are loops from second Kirchhoff's law.

enter image description here


Rearranging the BJT forward active current gain:

$$I_c = βI_b $$ $$I_b = \frac{I_c}{β} $$ $$\lim_{β \to \infty} I_b = 0$$

Practically this means that for large β you can ignore the base current. In that case Ic = Ie, and you can find Ie using Ohm's law.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.