Re: Nostalgia? Probably.
Impedance is the general case, resistance is specific to DC voltages and currents.
As you approach zero Hertz, inductors tend towards shorts and leave only their wire resistance, capacitors tend towards opens and leave only their insulation resistance. So the reactive parts of an impedance vanish, leaving only the resistive part.
As reactances are frequency-dependent, then any impedance with a non-zero imaginary part doesn't have a single value, it has a graph of complex impedance versus frequency. It seems quite reasonable for this graph to show where it passes through the zero Hertz plane. It's needed for completeness.
I have no problems with DC impedance.
We have silly terminology in various places. DC voltage is funny when you consider what that 'C' stands for.
470+j0 is still a resistor
David
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Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
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