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# Inductive coupling with/and AC? Answered

Several things I wanted to know, but couldn't find;

If 2 AC outputs are of the same amplitude, but of different frequency, will one necessarily be higher in power?

In a conventional transformer, (not resonant) does a higher frequency allow for higher efficiency coupling? Does this change if the transformer is resonant?

Is a 'standard' transformer more efficient than a resonant one at a very close range? (Provided that frequency, power, etc. are all the same?)

And lastly, does the resonant frequency of a resonant inductive coupling circuit affect the frequency at which it couples?
(did that all make sense?)

Thanks

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## Discussions

1.) No.
2.) No.
3.) clarify
4.) Yes, of course, you couple AT the resonant frequency. The ACT of coupling reduces the resonant peak.

You don't define "resonant transformer " in this context.

Resonant trasnsformer as in 2 resonant coils (same freq.) Does q factor go up with frequency or something? And if the load is too high, it's gonna throw the secondary off, right, but if it's too low, it'll not take all the energy transfered...

.  OK. It's been a long time since I studied AC circuits and almost as long since I used what I learned, but, for #1, if the amplitude is the same, won't the RMS voltage and power go up with frequency? Enquiring minds want to know.

Nope, RMS voltage is independent of frequency, and voltage is NOT THE SAME AS power - the source impedance isn't specified, if it was infinite, whatever voltage you see, you can't draw current, so you've no power.

.  I should know better than to trust my memory at my age.

> voltage is NOT THE SAME AS power
. I understand that, but if the load remains the same and you increase the voltage, don't current (I=E/R) and power (P=E²/R) go up also?

Wow! I couldn't even come close to answering this one. I only got one of four right.

I might be being pissy with definitions though I think I am strictly right.