Capacitor esr and impeadance?

Hello Hammy,

The term "ESR" in your newly selected capacitor, gives you a feeling of confidence. The questions is, is this justified or not?

It is very likely that both manufacturers used same test standard. So probably "impedance" as used by Rubycon is the same thing as "ESR" in the KXM datasheet. In other words; what is mentioned as ESR (at 100 kHz) is very likely nothing more then |Z| (as specified by Rubycon), so ESR will very likely give you a false feeling of confidence.

Also for the KXM component you see the significant dependence on temperature (so at =9610deg, Re(Z) will be almost |Z| and that equals (very likely) ESR). As I mentioned before, when Re(Z) is of importance for your application, you may run into problems as the spread is significant considering expected life time and environmental conditions.

BTW, the lifetime at 105degr for the Rubycon component is more then twice that of the KXM component.

Best regards,

Wim PA3DJS

Use an impedance analyzer like a HP4194A. For pulse amplifiers, I made a test jig that looks at capacitor characteristics with high current, fast rise time pulses.

ESR is important to the extent for determining the "esr zero". I knew it could vary over temp and manufacturing. I was surprised that it could vary over frequency (Resistive). This doesn't seem to be accounted for in all the literature I've read in loop design of SMPS.

I knew that caps both SMD and TH have reactive patristic's (LC) these vary with frequency. Even the appnote I show PHIL shows three 2.2mf caps with 30moHm esr for an AC sweep.

According to what I'm being told here those caps would have an esr in the single digit milliohm range at the switching freq. I do sweep the esr in spice AC simulation, MathCAD or EXCEL to see the effect of the zero moving by +/- 20% on PM. I guess I should increase this?

I was just looking for the lowest capacitance greater then 330uf at the best price that could handle the AC ripple current. I'm going to stick with my original selection the Rubycon component after reading your last response. Thank you for bringing that to my attention.

FWIW... That is what Rod Speed does when in trouble. They both post to the same groups, in the same vile way, and they both live in Australia. No country would not tolerate two of them, so it must be the same creature.

My news provider isn't giving me complete headers. I just checked Google when I couldn't retrieve my own message and see that half the responses for my question were dropped by my news provider. Of course all psycho Phils seem to get through!

My apologies to Jamie, Win and George Thanks for your attempt at trying to clear up my confusion. I wasnt ignoreing your responses I never got them.

Hello Hammy,

The ESR (Re(Z)) of the capacitor at high frequency is mostly determined by the electrolyte and not the real dielectric material providing the capacitance. The electrolyte makes the intimate contact with the aluminium oxide capacitor and is therefore in series with it. The Quality factor of the Aluminum oxide capacitor is very good, but the overall performance is reduces by the electrolyte.

The conductivity of the electrolyte is strongly frequency dependent (I know this from soil conductivity/permittivity versus frequency). It also depends on the separating paper (as at very low frequency ions must propagate through this material).

Wim PA3DJS

What ever you say Phil.

Your lack of creativity kind of shows your impotence.

Btw Phil, I worked at a capacitor manufacturer facility where these components were used in Military applications like the Patriot missiles and the like. I was one of the guys that maintained the calibration equipment along with R&D.

Kind of scares you doesn't it? :)

P.S. Get a life.

Have a miserable day!

Thank you for your patience and for taking the time to provide a detailed explanation.

I obviously don't understand capacitors as well as I thought. I will do some more reading including the pdf you linked to.

Thanks to all who provided meaningful input even your first response was helpful Phil unfortunately you degenerated into an imbecile after that.

Jaimie = Maynard A. Philbrook = a LYING PILE OF S*IT

He is radio ham " KA1LPA " - so par for the course.

Maynard is a genetic freak - he is part donkey.

He has the brain of one.

Heee, hawww........

...... Phil

Jamie = Maynard A. Philbrook = a LYING PILE OF S*IT

He is radio ham " KA1LPA " - so par for the course.

Maynard is a genetic freak - he is part donkey.

He has the brain of one.

Heee, hawww........

...... Phil

"Hammy"

..... Phil

...

The original Star Wars, bar scene... unprovoked, the wanted man confronts Luke. Obi-Wan tries to calm him, offering to buy him a drink... the bad guy goes ballistic. I love that scene, it is like a painting. Needless to say, it reminds me of Phil/Rod/whatever.

Phil, you are so out of your league boy, you should stop before the guy behind you runs you over. Because you sure aren't ahead of no one.

And Phil, there are induction issues with electrolytic type caps due to their constructions. Also chemical reactions with the electrolyte and the types of paper used, along with SR issues and the type of lead bonding used.. You're suck a putz.

Go blow it out your finger Philis..

I think your mother must of used you for a wheel wedge one to many times. Your brains, what little have, are not properly functioning.