Comments on "Energy in lossless and low-loss networks and Foster\´s reactance theorem

For the original article see ibid., vol.36, no.4, p.561-7 (1989). The commenter points out that a general relation for the energy stored in a reactive network driven by a sinusoidal source provided in the above-mentioned paper appears in a book by H.W. Bode (1945). The author agrees that the result of equation (17) in his paper is contained implicitly in equation (9.16) in Bode´s book, noting that he was not aware of this result. On the other hand, he points out that the derivation in his paper is more general and applies to both lumped and distributed networks. It is also general in a sense that it applies to any lossless physical system, provided a certain condition is met. He maintains that the derivation in his paper is much simpler and more lucid than the one based on network energy functions methods.<>