Below is a two-port network representation:
And what I understand so far according to the definition of a two-port network, there must be two independent variables and two dependent variables as in the above figure. And a port's input and output current should be same to call it a port.
But how about the following circuit from this text?:
Is the above circuit a "passive two-port network" as the text claims? Or is it a one-port passive network?
There is only one independent source in that network above which is Vin. Vout is dependent on Vin; so it is not independent for me at least.
So is this type of passive networks are two-port or one port network?
Is there a practical example for a two-port passive network ?