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# dc inductor

do inductors work with pulsed dc? like would they become more resistive with frequency? Or would they do nothing because it's not ac and the electrons can't "bump" into eachother.

330Views5Replies

do inductors work with pulsed dc? like would they become more resistive with frequency? Or would they do nothing because it's not ac and the electrons can't "bump" into eachother.

## Discussions

Sure. Look up the "step response" of an inductor, and apply that to each edge of your "pulses." Alternately, invoke Fourier analysis (qualitatively, this just says that you can construct any repetitive waveform using a sum of sine waves), and conclude that an inductor will attenuate the different frequency components of a (say) square wave different amounts. I think the step-response model is one that shows up more frequently in modern electronics; a switchmode power supply uses those principles to do voltage conversion.

I'm sorry, I think my head just exploded when i googled it. I guess bottom line, will it work in a tank circuit?

I dunno. My impression is that transformer-like circuits (including inductive power transfer) are significantly more efficient with sine waves. With pulsed DC, you sort of lose a good part of power near the edges, because (essentially) they represent a frequency that the circuit isn't designed to handle. You put in a square wave, and you get out something that looks more like a sinewave (with peaks in the middle of the squares), but you've lost the power represented by the difference.... (in the attached picture, a "lossy" power transfer might have an input waveform like the green square wave, an output like the red "sine" wave, and the blue hash represents lost power.) (But I've never done an power transfer setup...)

well, I'm working on inductive power transfer (with puffin juice) and I was just woundering if pulsed dc would work instead of ac. and what would the resistive value of it at a certain frequency? would the resistive value only be the resistance of the wire? Basically a tank circuit off of pulsed dc, would it work?

It depends on what you mean by "work". If a "field" is created, than then disconnected, the field collapses and a reverse voltage will be produced.