Y-parameters

It is usually possible to choose the port voltages, V₁, V₂, ... independently (Imagine connecting an independent voltage source across each port). A given set of port voltages determines the resulting port currents, I₁, I₂, ...

The relationship between port currents and port voltages is the admittance matrix Y:

The entries Y_ij of the admittance matrix are often called the Y-parameters.