The subject of electrical impedance is on the syllabi of most undergraduate courses in physics and
electrical engineering. For example, Richard Feynman in his famous undergraduate text Lectures on
Physics shows how to calculate the impedance of an infinite LC ladder. However, the formula he
obtains has no useful physical interpretation if considered in the steady state frequency domain. In
fact the value of this impedance becomes infinite unless one assumes that the energy flow along the
infinite LC ladder is spatially uniform and in one direction only. This ad-hoc assumption, which
renders the solution non-causal, is entirely unnecessary if the problem is considered in the time
domain. It is important for students to appreciate that the concept of impedance works well only in
dissipative circuits where the effects of transients are largely short lived. The purpose of this
paper is to show that the same problem treated in the time domain by the Laplace transform method
pr…