# circuit (skrf.circuit)¶

Circuit class represents a circuit of arbitrary topology, consisting of an arbitrary number of N-ports networks.

Like in an electronic circuit simulator, the circuit must have one or more ports connected to the circuit. The Circuit object allows one retrieving the M-ports network, where M is the number of ports defined.

The results are returned in Circuit object.

## Building a Circuit¶

 Circuit(connections) Creates a circuit made of a set of N-ports networks. Circuit.Port(frequency, name[, z0]) Return a 1-port Network to be used as a Circuit port. Circuit.Ground(frequency, name[, z0]) Return a 1-port network of a grounded link, to be used in a Circuit description.

## Representing a Circuit¶

 Circuit.plot_graph(**kwargs) Plot the graph of the circuit using networkx drawing capabilities.

## Network Representations¶

 Circuit.network Return the Network associated to external ports Circuit.s Return the global scattering parameters of the circuit, that is with both “inner” and “outer” ports Circuit.s_external Return the scattering parameters for the external ports Circuit.s_active(a) Return active s-parameters of the circuit’s network for a defined wave excitation a. Circuit.z_active(a) Return the active Z-parameters of the circuit’s network for a defined wave excitation a. Circuit.y_active(a) Return the active Y-parameters of the circuit’s network for a defined wave excitation a. Circuit.vswr_active(a) Return the active VSWR of the circuit’s network for a defined wave excitation a. Circuit.port_z0 Return the external port impedances

## Circuit internals¶

 Circuit.networks_dict([connections, min_nports]) Return the dictionnary of Networks from the connection setup X Circuit.networks_list([connections, min_nports]) Return a list of unique networks (sorted by appearing order in connections) Circuit.connections_nb Return the number of intersections in the circuit. Circuit.connections_list Return the full list of connections, including intersections. Circuit.nodes_nb Return the number of nodes in the circuit. Circuit.dim Return the dimension of the C, X and global S matrices. Circuit.intersections_dict . Circuit.port_indexes Return the indexes of the “external” ports. Circuit.C Return the global scattering matrix of the networks Circuit.X Return the concatenated intersection matrix [X] of the circuit.

## Graph representation¶

 Circuit.graph() Generate the graph of the circuit. Circuit.G Generate the graph of the circuit. Circuit.edges Return the list of all circuit connections Circuit.edge_labels Return a dictionnary describing the port and z0 of all graph edges.