Vratsanos' theorem [Letter from Mr. Ansell]

As reported in the September, 1957 issue of these TRANSACTIONS, J. Vratsanos [in "Calculation of current distribution in & linear network," Arch. Elekt. Uberfr., vol. 11, pp. 70-80; February, 1957] observes that if a current I flows through a linear 1-port, the impedance between the 2 terminals being R, then the current i flowing through any impedance T of the network is given by a particular relation. The commentor shows that one may find an analogous equation for the resistive n-port by considering what happens if some resistance r is changed slightly.