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phoebdroid t1_it7gsnl wrote

Reply to comment by TrueSelenis in Audiophile terminologies. by easypeace420

Well as soon as we are conducting electricity through a closed circuit, we can talk about resistance and impedance right ? Cables have impedance, components have impedance , so on and so forth. While I'm not an electrical engineer, about something that trivial I fail to see what's wrong with that statement.

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TrueSelenis t1_it7igju wrote

OK I will bite.

impedance does not equal electrical resistance.

Components like capacitors and inductors behave very differently in DC systems and AC systems.

In DC Systems they have only a normal electrical resistance value except for the short period when current is changing when a capacitor is discharging for instance. Capacitors for instance are isolators in DC systems.

In AC systems capacitors and inductors are not isolators anymore but introduce a phase shift in the AC current. In the relevant equations their influence needs to be expressed as a complex value if you want to see the full picture.

When you are simplifying AC equations, you can apply a so called impedance value to such systems for some equations which then behaves like resistance (and has the same unit as electrical resistance) as long you can ignore phase shift behavior which is not always possible.

So you really do not use the word impedance for DC systems. It has a very subtle technical meaning.

Mathematically it is a combination of electrical resistance and these phaseshifting effects in AC systems.

Cables usually don't have an impedance value but just a electrical resistance value because you would have to coil them really tightly and introduce an AC current in order to have a coil again and then its not a normal cable anymore.

Edit: and I am completely skipping even more subtle concepts like pulse propagation and modulation, shielded cables and much much more.

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phoebdroid t1_it7jadb wrote

Hey thanks for the enlightenment, I did think DC resistance also meant impedance. So when I measure the resistance of a cable it's not impedance, just resistance then.

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TrueSelenis t1_it7o1be wrote

no problem. electrical engineering is a fascinating rabbit hole and there are many good sources from which you can get the basics and then dive deeper into the stuff that interests you.

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MentalThroat7733 t1_it9zqps wrote

Similarly apparent power where you often treat watts and volt-amps like they're the same when they aren't. AC is hard 😂

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