I'm bit confused about what Input Impedance or Output Impedance is. I tried to read Wikipedia's page (https://en.wikipedia.org/wiki/Input_impedance) but I find it hard to follow.
Is the Input Impedance of a circuit (defined between two terminals A and B) the same as the equivalent impedance obtained by applying Thévenin's Theorem? What is the Output Impedance instead?
I'm interested in the general theory, an example (with the diagram of a circuit showing input and output Impedance) would be really appreciated