In a practise exam question I am given a circuit of a BJT differential amplifier and told to show that these equations are true:
I am told to do it using the hybrid-pi model.
Here is a picture of the circuit:
I know how to replace the transistors with the hybrid-pi model, but am not sure how to analyse the circuit from there. I've been having a great deal of trouble with this. Could somebody please show me how to get Ad and Acm?
Edit: I've received some responses but am still confused so will update my question to give a clearer picture of what I understand so far.
Here is the circuit I get when I replace the transistors with the hybrid-pi model.
I also understand that in common mode V1 = V2 = Vcm, and in differential mode V1 = Vd/2 and V2 = -Vd/2
Some of the things confusing me: When I tried to research problems similar to this on google some websites told me that the output would be Vo = Vo2 - Vo1, Yet in this question it looks like I'm supposed to just consider one output at a time, choosing either Vo1 or Vo2. I am also confused by Vpos and Vneg - should I be considering them in my calculations or ignoring them?