Hi Jim, I am behind and trying to catch-up, and you triggered my latent thoughts about ESR stuff

As regards the previous comments about? one or the other, it seems to me the “better” or the “best” one ?is the one with the lesser ESR, at least in that case.? ?“Better” ?and “best” ?are always comparative. ?????The best score in golf is a bit different than the best score in basket ball. ?

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If there is an ultimate/ ideal Best ,for ESR, ?some might say it is zero .. but hold on, now the series inductance won’t be swamped by resistance, so should include the ESL ?????when you squeeze the R out of caps and the R out of L’s , circuit Q’s get high ?and ringing can easily take place? . my guess is that 1960’s power supplies will be stiffer and stiffer as you squeeze out the series part of the ESR, but ?most reasonable leakage in ?the ESR value will hardly matter.

But when it comes to switching PS, it is rather obvious that series R is going to produce heat etc and removing series R ??might cause ringing. I leave that to gen X, Y, Z, and W, to worry about that?? ???

but ?whe you generalize, and consider RF circuits, sticking in a new cap with very low ESR might be enough to allow spurious resonances to show up as ringing. They rarely if even spoke the ESR, series resistance, or even leakage AFIK .. ??which is 1/Googolplex of what I should know.

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