Before revision: They will be equal if the network is symmetrical, however physically symmetry is not a necessary condition for the impedances to be equal.Bird, p. 594 Examples A simple generic L-circuit is shown in the diagram consisting of a series impedance Z and a shunt admittance Y.
After revision: Iterative impedance of a simple generic L-circuitThey will be equal if the network is symmetrical, however physically symmetry is not a necessary condition for the impedances to be equal.Bird, p. 594 Examples A simple generic L-circuit is shown in the diagram consisting of a series impedance Z and a shunt admittance Y.