Capacitor ESR ??

Win,

For 2 R's and 2 C's, a good initial guess was each C was half the cap's "DC" capacitance and each R was equal to the cap's ESR. So my initial guess for 3 R's and 3 C's is each C is 1/3 the total cap an each R is equal to the nominal ESR.

--Mike

I read in sci.electronics.design that John Popelish wrote (in ) about 'Capacitor ESR ??', on Thu, 12 Feb 2004:

You can separate parallel and series losses by measuring at more than one frequency; two if inductance is negligible, three if it isn't. I'd need to think about hysteresis loss: it isn't something that is normally significant in capacitors.

That still gives you a lumped 'equivalent series resistance' figure, and often not a useful one, because you won't be subjecting the capacitor to frequencies anywhere near the resonance.

I read in sci.electronics.design that Mike Engelhardt wrote (in ) about 'Capacitor ESR ??', on Thu, 12 Feb 2004:

If you use more than one R and C, you need to add inductors as well.

About 1 Ohm for small values (~1uF), 300 mOhm for medium range, say 10 to 100 uF, and 100 mOhm for largish values, above 100 uF.

Aluminium or tantalum doesn't make much difference. It matters more whether the manufacturer cares about ESR or not.

Add about 4nH of inductance for each tenth of an inch between the legs, if that matters.

Those are ballpark figures, of course.

Jeroen

John Woodgate wrote: (snip)

Think about high K ceramic capacitors.

I'd really rather not. Ugh!(;-)

I agree that they can be hysterical; you can hear them screaming if you develop any audio voltage across them.

John,

It's been a while since I looked at this, but when I did, the resistive impedance sufficiently swapped the inductive reactance to negate it's need to model. Anyway, the conclusion I came to was that two R's and two C's was accurate enough.

--Mike

I wonder if that's piezo effect . . . "crystal" or ceramic microphones can be acoustic radiators if you apply voltage across them.

On Thu, 19 Feb 2004 08:48:14 -0800, "Mike Rocket J. Squirrel Elliott" Gave us:

Of course it is. Just not to the same degree that bona fide piezo ceramic materials exhibit.

How would one model that loss in a ceramic cap?

On Fri, 20 Feb 2004 05:48:05 -0800, "Mike Rocket J. Squirrel Elliott" Gave us:

dielectric. Standard capacitor stuff. The pressure imposed on the dielectric behaves similarly. Why is it a loss?

When a cap is charged, there is an attraction between the plates.

When discharged, it releases.

If a ceramic has microphonic behaviors, how does it represent a loss? It could merely be that the firmness of the media it is constructed from allows it to be audible. I mean maybe it is a loss factor... I am just asking as well here... with some conjecture included.

It makes sound, otherwise acoustic energy for free?

Furthermore, due to mechanical resonances, the loss vs. frequency is non-linear in an odd way. You could model this with a network of several RLC's, but it's easier to just remember that ceramic capacitors are crap.

-----

I read in alt.binaries.schematics.electronic that Mike Rocket J. Squirrel Elliott wrote (in ) about 'Capacitor ESR ??', on Thu, 19 Feb 2004:

Yes, it is.

-- Regards, John Woodgate, OOO - Own Opinions Only. The good news is that nothing is compulsory. The bad news is that everything is prohibited.

I read in alt.binaries.schematics.electronic that DarkMatter wrote (in ) about 'Capacitor ESR ??', on Fri, 20 Feb 2004:

It is accompanied by hysteresis, and that does cause a power loss, juts as it does in a ferromagnet.

Well now -- if you just want to take the simple, obvious approach, I suppose that /might/ work. ;-)

On Fri, 20 Feb 2004 07:58:55 -0800, "Mike Rocket J. Squirrel Elliott" Gave us:

When it pushes, and releases, the material pushes back.

If it is microphonic, perhaps it has defective internal terminations, or are you saying that they all sing?

I still don't see how it is a loss. The dielectric constant probably includes such physical flexures whereas a polymer type dielectric only flexes internally at the lattice level. Still, it has hysteresis as well.

In this case, the hysteresis sings audibly. I don't see how it is a loss though. It is more like a response to stimulus, but I don't see that it would have much consumption, if any. It very well could be just that though.

On Fri, 20 Feb 2004 13:48:32 -0500, Ben Bradley Gave us:

That would depend on the application. One can fit six of our miniature 12kV HV supplies into a cigarette pack.

With poly caps, it would take more than a cigarette pack for a single supply.

In news: snipped-for-privacy@4ax.com (DarkMatter):

If a light bulb gives off light, is there no energy used in creating that light?

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