In electrical circuit theory, a port is a pair of terminals connecting an electrical network or circuit to an external circuit, as a point of entry or exit for electrical energy. A port consists of two nodes (terminals) connected to an outside circuit which meets the port condition – the currents flowing into the two nodes must be equal and opposite.
Coaxial circulators. Circulators have at least three ports
A Moreno coupler, a type of waveguide directional coupler. Directional couplers have four ports. This one has one port permanently terminated internally with a matched load, so only three ports are visible. The ports are the openings in the centres of the waveguide flanges
The Π pad is a specific type of attenuator circuit in electronics whereby the topology of the circuit is formed in the shape of the Greek capital letter pi (Π).
Unbalanced source and load. V1o is open circuit voltage of the source.
Conversion of two-port admittance parameters to pi pad
Conversion of tee pad to pi pad