Sorry to create a new thread for this, but since there is no sqt I thought I'd just do it here. I'm having some trouble visualizing how exactly the small signal model for transistors works (BJT, JFET, MOSFET). In particular, I got a problem like pic related except I'm at low frequency and can replace the capacitors for open circuits. I understand, based on what I found online, that once the transistor is properly biased, I can replace the transistor symbol for the small signal four port network equivalent circuit, and then make my DC sources zero.
This is the step I don't understand... Making sure my transistor is properly biased means, I imagine, making sure that saturation has been reached, that is that drain voltage is higher than the saturation drain voltage. But I don't see why I can then just set all DC sources to zero. Is it because I don't care what the DC voltage is, and only care about the small oscillating signal on top of it? And for the analysis is the same whether that small signal is oscillating around zero than around any other DC voltage value?
Thx for the help