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[email protected] jurb6006@gmail.com is offline
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Default One last ESR question

Topresponding to get above all the BS, all capacitors have ESR. All capacitors have ESL as well as leakage. It is a matter of what is important and what is not. to understand this you need to know what these capacitors are for.

There are small caps used to tune RF circuits and all that, and they usually have a very low leakage and ESL. The ESR is not al that critical in that type of circuit. It is important, but there are aot mor eimportant things like ESL and the accuracy of the capacitance, in percent. Not like electrolytics where anytihng above is good until it hits ridiculous.

Another type of cap is used in signal. it is sometimes like the RF cap, like in tone control circuits fro example, they set the frequency. Or any frequency discrininating network. The capacitance is many times more critical than ESR. However ESL can still be a problem.

Electrolytics are used a different way. First of all, their value is almost never critical. Seruiously, in some cases you can put a 100 uF where a 1,000 uF was and it will work fine. Actually tis is especially true of olders lytics.

Speaking of which, this ESR comes on but all the cpacitance is still there only aplies to newer ones. The older ones actually would lose capacitance. In fact I got one at workk right now. Filter cap in an old tube amp. It has a perfect sawtooth across it, absolutely none of that characteristic hump from the rectifier conduction. It has lost capacitance. Old paper job.

Like with replacing caps, electrolytics ? The value almost does not matter. Almost. It is all switched mode now, anyting over 0.01 uF would work.

If it canhandle the ripple current.

now there are some thihngs where they want the sources to decay in an orderly fashion at power down or power removal. Well OK, but in those applications they should be using better grade caps.

I'm sure they are.

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