John Larkin <jlarkin@highland_atwork_technology.com> wrote:> On Thu, 17 Oct 2019 20:45:36 -0000 (UTC), Steve Wilson <no@spam.com> > wrote:>>John Larkin <jlarkin@highland_atwork_technology.com> wrote:>>> On Thu, 17 Oct 2019 17:13:40 -0000 (UTC), Steve Wilson <no@spam.com> >>> wrote:>>>>jlarkin@highlandsniptechnology.com wrote:>>>>> Quite welcome. It's good to have some real numbers on (one) real >>>>> cap.>>>>Yor data is valid for that capacitor only.>>> Excellent whining.>>> It's more data than data on no capacitors. I suspect that all wet >>> aluminum electros will have similar shaped curves, so will be >>> self-stabilizing in series strings.>>Why suspect? Why not read some of the links I provided? For example, see >>Page 3 of>>https://jianghai-europe.com/wp-content/uploads/8-Jianghai-Europe-E-Cap- >>Leakage-Current-AAL-2018-09-18.pdf>>Quote:>>The operating leakage current [5] as a measure of the forming condition >>of anode foil depends on the time, applied voltage, temperature, and >>history of the capacitor (fig. 4 (a) ~ (c)). Typical values of the >>operational leakage current range between approx. 5 ~ 15% of the data >>sheet value of leakage current amount and are usually reached after >>several ten minutes of continuous operation.>>The leakage current specified in the data sheet shall be valid even >>after a long, voltage-free storage period and has therefore a much >>higher numerical value than the operating leakage current. The oxide >>layer dissolves to a certain extent as a function of temperature and >>electrolyte composition, because without any voltage applied, the oxide >>layer cannot regenerate ("self-healing") [5].>>While low-voltage capacitors (up to 100 V rated voltage) with >>solvent-based electrolyte systems are usually very stable, high-voltage >>capacitors (from 160 V rated voltage) with ethylene glycole-based >>electrolytes and in particular so-called "low ESR" types with aqueous >>electrolytes may exhibit an increase of leakage currents throughout >>their lifetime.>>15 ~ 30 minutes of operation of the electrolytic capacitors via a >>resistor (low-voltage: 100 Ohm, high-voltage: 1 k, see [7], section 4.1 >>"pretreatment") at a voltage increased gradually to rated voltage may >>heal the weak spots in the dielectric and lower the leakage current >>below the data sheet value.>>>>Every cap will be different. There are many different electrolytes >>>>with different characteristics, such as non-solid borax or organic, >>>>non-solid water-based, solid manganese dioxide, solid conducting >>>>polymer, non-solid hybrid electrolyte, etc., and the leakage >>>>characteristics will be different for each type. See Wikipedia, >>>>"Aluminum electrolytic capacitor", at>>>>https://en.wikipedia.org/wiki/Aluminum_electrolytic_capacitor>>> Superb, well-researched whining.>>> I used a standard Panasonic aluminum electrolytic.>>> Measure something else and post it here.>>You are trying to pretend the measurement you made on one capacitor is >>the first time such a measurement has been made. In fact, you said so >>yourself.> I said "possibly" the only one available online, after several minutes > of intense web searching. If you can find an electrolytic cap leakage > measurement, past rated voltage, with real numbers, not fuzzy > cartoons, please post the link for us.Why measure past the rated voltage? You are never going to operate there. You simply risk damaging the capacitor for no good reason. The curve shown in fig. 4 is a generic curve. The actual curves are different for each capacitor, and depend on variables such as those described above. So it is impossible to represent all capacitors at once.>>I posted numerous links that show your assumption is not valid.> I didn't assume anything. I measured something.Your data is meaningless. As mentioned elsewhere, capacitor manufacturers can give actual curves for their capacitors. You can compare your data against the spec to see if your cap is out of spec.> Try it; it's more fun than cutting and pasting a lot of text.Your data is meaningless.> There is a >>tremendous amout of knowlege in those links.> Lotta words, no numbers. Engineers need numbers.Nah. Real engineers need equations. Do an exponential fit to your data. The Stdev will give an indication of the quality of the measurement. The equation will allow you to compare other capacitors. The curve can be compared to actual specs from manufacturers. You need to also try measuring the capacitor voltage with a constant current source. That could give valuable new information.
Film capacitor as power-supply filter
Started by ●October 7, 2019
Reply by ●October 19, 20192019-10-19
Reply by ●October 19, 20192019-10-19
Steve Lunatic Wilson wrote: ----------------------------> > > Why measure past the rated voltage? You are never going to operate there. > You simply risk damaging the capacitor for no good reason. > > The curve shown in fig. 4 is a generic curve. The actual curves are > different for each capacitor, and depend on variables such as those > described above. So it is impossible to represent all capacitors at once. > > You need to also try measuring the capacitor voltage with a constant > current source. That could give valuable new information. > >** This fuckwit troll is a pernicious false arguer and incorrigible context shifter. He is delusional to the extent he literally believes his own bullshit. Prefect candidate for the "Church of Scientology" don't you think ? If he ain't one already that is ... .... Phil
Reply by ●October 19, 20192019-10-19
On Saturday, October 19, 2019 at 3:48:18 AM UTC-4, Steve Wilson wrote:> Why measure past the rated voltage? You are never going to operate there. > You simply risk damaging the capacitor for no good reason.> Nah. Real engineers need equations. Do an exponential fit to your data.The 'need equtions' is the reason you want to measure past the rated voltage; there's not much validity to an equation if there are singularities just outside the measured range (because, for instance, any polynomial fails to handle a singularity). When you apply the capacitor, it's sensible to stick to the range the manufacturer recommends (that's the way the manufacturer and user can coordinate), but NOT for the purpose of information-gathering. MOS devices get damaged quickly outside their recommended range, but not usually capacitors. If in doubt, overvoltage some ceramics and test 'em for changes. I've (carefully) overvoltaged electrolytics to bring leakage down after storage; it never failed.
Reply by ●October 19, 20192019-10-19
On Sat, 19 Oct 2019 07:48:13 -0000 (UTC), Steve Wilson <no@spam.com> wrote:>John Larkin <jlarkin@highland_atwork_technology.com> wrote: > >> On Thu, 17 Oct 2019 20:45:36 -0000 (UTC), Steve Wilson <no@spam.com> >> wrote: > >>>John Larkin <jlarkin@highland_atwork_technology.com> wrote: > >>>> On Thu, 17 Oct 2019 17:13:40 -0000 (UTC), Steve Wilson <no@spam.com> >>>> wrote: > >>>>>jlarkin@highlandsniptechnology.com wrote: > >>>>>> Quite welcome. It's good to have some real numbers on (one) real >>>>>> cap. > >>>>>Yor data is valid for that capacitor only. > >>>> Excellent whining. > >>>> It's more data than data on no capacitors. I suspect that all wet >>>> aluminum electros will have similar shaped curves, so will be >>>> self-stabilizing in series strings. > >>>Why suspect? Why not read some of the links I provided? For example, see >>>Page 3 of > >>>https://jianghai-europe.com/wp-content/uploads/8-Jianghai-Europe-E-Cap- >>>Leakage-Current-AAL-2018-09-18.pdf > >>>Quote: > >>>The operating leakage current [5] as a measure of the forming condition >>>of anode foil depends on the time, applied voltage, temperature, and >>>history of the capacitor (fig. 4 (a) ~ (c)). Typical values of the >>>operational leakage current range between approx. 5 ~ 15% of the data >>>sheet value of leakage current amount and are usually reached after >>>several ten minutes of continuous operation. > >>>The leakage current specified in the data sheet shall be valid even >>>after a long, voltage-free storage period and has therefore a much >>>higher numerical value than the operating leakage current. The oxide >>>layer dissolves to a certain extent as a function of temperature and >>>electrolyte composition, because without any voltage applied, the oxide >>>layer cannot regenerate ("self-healing") [5]. > >>>While low-voltage capacitors (up to 100 V rated voltage) with >>>solvent-based electrolyte systems are usually very stable, high-voltage >>>capacitors (from 160 V rated voltage) with ethylene glycole-based >>>electrolytes and in particular so-called "low ESR" types with aqueous >>>electrolytes may exhibit an increase of leakage currents throughout >>>their lifetime. > >>>15 ~ 30 minutes of operation of the electrolytic capacitors via a >>>resistor (low-voltage: 100 Ohm, high-voltage: 1 k, see [7], section 4.1 >>>"pretreatment") at a voltage increased gradually to rated voltage may >>>heal the weak spots in the dielectric and lower the leakage current >>>below the data sheet value. > >>>>>Every cap will be different. There are many different electrolytes >>>>>with different characteristics, such as non-solid borax or organic, >>>>>non-solid water-based, solid manganese dioxide, solid conducting >>>>>polymer, non-solid hybrid electrolyte, etc., and the leakage >>>>>characteristics will be different for each type. See Wikipedia, >>>>>"Aluminum electrolytic capacitor", at > >>>>>https://en.wikipedia.org/wiki/Aluminum_electrolytic_capacitor > >>>> Superb, well-researched whining. > >>>> I used a standard Panasonic aluminum electrolytic. > >>>> Measure something else and post it here. > >>>You are trying to pretend the measurement you made on one capacitor is >>>the first time such a measurement has been made. In fact, you said so >>>yourself. > >> I said "possibly" the only one available online, after several minutes >> of intense web searching. If you can find an electrolytic cap leakage >> measurement, past rated voltage, with real numbers, not fuzzy >> cartoons, please post the link for us. > >Why measure past the rated voltage? You are never going to operate there. >You simply risk damaging the capacitor for no good reason.The issue was series strings of electrolytic caps, where the total supply voltage is more than the rated voltage of the caps. Film caps can blow up in that situation. What do lytics do? Answer: their IV curves make them safely self-equalize.> >The curve shown in fig. 4 is a generic curve. The actual curves are >different for each capacitor, and depend on variables such as those >described above. So it is impossible to represent all capacitors at once. > >>>I posted numerous links that show your assumption is not valid. > >> I didn't assume anything. I measured something. > >Your data is meaningless. As mentioned elsewhere, capacitor manufacturers >can give actual curves for their capacitors.Post a link of leakage past rated voltage. Real data, not faked cartoons. You can compare your data>against the spec to see if your cap is out of spec. > >> Try it; it's more fun than cutting and pasting a lot of text. > >Your data is meaningless.Since you probably don't design electronics, it is meaningless to you.> >> There is a >>>tremendous amout of knowlege in those links. > >> Lotta words, no numbers. Engineers need numbers. > >Nah. Real engineers need equations. Do an exponential fit to your data. The >Stdev will give an indication of the quality of the measurement. The >equation will allow you to compare other capacitors. The curve can be >compared to actual specs from manufacturers. > >You need to also try measuring the capacitor voltage with a constant >current source. That could give valuable new information.How would that be different? You'd get the same data points, just slower. -- John Larkin Highland Technology, Inc lunatic fringe electronics
Reply by ●October 19, 20192019-10-19
On Sat, 19 Oct 2019 03:37:00 -0700 (PDT), Phil Allison <pallison49@gmail.com> wrote:>Steve Lunatic Wilson wrote: > >---------------------------- >> >> >> Why measure past the rated voltage? You are never going to operate there. >> You simply risk damaging the capacitor for no good reason. >> >> The curve shown in fig. 4 is a generic curve. The actual curves are >> different for each capacitor, and depend on variables such as those >> described above. So it is impossible to represent all capacitors at once. >> >> You need to also try measuring the capacitor voltage with a constant >> current source. That could give valuable new information. >> >> > >** This fuckwit troll is a pernicious false arguer and incorrigible context shifter. > >He is delusional to the extent he literally believes his own bullshit. > >Prefect candidate for the "Church of Scientology" don't you think ? > >If he ain't one already that is ... > >He argues out of emotion rather than reason. I have several anti-fans here who are dying to show me wrong, and will commit any bogus mental contortion in that cause. This is amusing, because I'm really interested in how people reason toward truth, and especially how they don't. -- John Larkin Highland Technology, Inc lunatic fringe electronics
Reply by ●October 19, 20192019-10-19
On Sat, 19 Oct 2019 07:29:50 -0700 (PDT), whit3rd <whit3rd@gmail.com> wrote:>On Saturday, October 19, 2019 at 3:48:18 AM UTC-4, Steve Wilson wrote: > >> Why measure past the rated voltage? You are never going to operate there. >> You simply risk damaging the capacitor for no good reason. > >> Nah. Real engineers need equations. Do an exponential fit to your data. > >The 'need equtions' is the reason you want to measure past the rated voltage; >there's not much validity to an equation if there are singularities just outside >the measured range (because, for instance, any polynomial fails to handle a singularity). > >When you apply the capacitor, it's sensible to stick to the range the manufacturer >recommends (that's the way the manufacturer and user can coordinate), but NOT for >the purpose of information-gathering. > >MOS devices get damaged quickly outside their recommended range, but not usually capacitors.Standard mosfets generally die at gate voltages around 70ish, maybe 5x rated abs max. The self-protecting ones zener at maybe 44 volts on the gate. Most mosfets will avalanche at high drain voltages, maybe 1.5 or so times abs max, and are then damaged by excess dissipation. Some just die without avalanching. The EPC GaN fets die without warning at a bit over 2x max drain voltage and have more complex gate voltage behavior. The Cree SiC fets avalanche at around 1.4x rated drain voltage, and like the mosfets just get hot. You can kill them with a modest gate over-drive, which is unfortunate because they need close to abs max gate drive to switch well.>If in doubt, overvoltage some ceramics and test 'em for changes.Ceramics are usually happy at several, sometimes ten or twenty, times rated voltage. But they tend to run out of capacitance. -- John Larkin Highland Technology, Inc lunatic fringe electronics
Reply by ●October 19, 20192019-10-19
jla...@highlandsniptechnology.com wrote: --------------------------------------> > >Steve Lunatic Wilson wrote: > > >> > >> > >> Why measure past the rated voltage? You are never going to operate there. > >> You simply risk damaging the capacitor for no good reason. > >> > >> The curve shown in fig. 4 is a generic curve. The actual curves are > >> different for each capacitor, and depend on variables such as those > >> described above. So it is impossible to represent all capacitors at once. > >> > >> You need to also try measuring the capacitor voltage with a constant > >> current source. That could give valuable new information. > >> > >> > > > >** This fuckwit troll is a pernicious false arguer and incorrigible > > context shifter. > > > >He is delusional to the extent he literally believes his own bullshit. > > > >Prefect candidate for the "Church of Scientology" don't you think ? > > > >If he ain't one already that is ... > > > > > > He argues out of emotion rather than reason. >** You mean, just like you do ?> I have several anti-fans > here who are dying to show me wrong, and will commit any bogus mental > contortion in that cause. >** I *do* know the feeling ... Because I go hard against all the fools & trolls on this and other NGs, I get the same malicious treatment.> This is amusing, because I'm really interested in how people reason > toward truth, and especially how they don't.** Same interest here - the sheer, bloody irrationality of most people is STAGGERING ! The fact was driven home to me forcefully soon as I began posting on usenet, about 20 years ago. People make up their minds about something in a flash, using great gobs of false logic plus "intuition" - then will not back down at any price. That so many seemingly bright people go right through college and university WITHOUT learning clear thinking or how to spot and avoid logical fallacies is a crime. I could go on and on ... .... Phil
Reply by ●October 19, 20192019-10-19
On Sat, 19 Oct 2019 15:23:03 -0700 (PDT), Phil Allison <pallison49@gmail.com> wrote:>jla...@highlandsniptechnology.com wrote: > >-------------------------------------- >> >> >Steve Lunatic Wilson wrote: >> > >>> >> >> >> >> Why measure past the rated voltage? You are never going to operate there. >> >> You simply risk damaging the capacitor for no good reason. >> >> >> >> The curve shown in fig. 4 is a generic curve. The actual curves are >> >> different for each capacitor, and depend on variables such as those >> >> described above. So it is impossible to represent all capacitors at once. >> >> >> >> You need to also try measuring the capacitor voltage with a constant >> >> current source. That could give valuable new information. >> >> >> >> >> > >> >** This fuckwit troll is a pernicious false arguer and incorrigible >> > context shifter. >> > >> >He is delusional to the extent he literally believes his own bullshit. >> > >> >Prefect candidate for the "Church of Scientology" don't you think ? >> > >> >If he ain't one already that is ... >> > >> > >> >> He argues out of emotion rather than reason. >> > >** You mean, just like you do ?Playing with twits doesn't count. That's just sport. Electronics is pretty check-able, so emotional delusions don't get very far.> > >> I have several anti-fans >> here who are dying to show me wrong, and will commit any bogus mental >> contortion in that cause. >> > >** I *do* know the feeling ... > >Because I go hard against all the fools & trolls on this and other NGs, I get the same malicious treatment. > > >> This is amusing, because I'm really interested in how people reason >> toward truth, and especially how they don't. > >** Same interest here - the sheer, bloody irrationality of most people is STAGGERING ! > >The fact was driven home to me forcefully soon as I began posting on usenet, about 20 years ago. People make up their minds about something in a flash, using great gobs of false logic plus "intuition" - then will not back down at any price. > >That so many seemingly bright people go right through college and university WITHOUT learning clear thinking or how to spot and avoid logical fallacies is a crime. > >I could go on and on ... > > >.... Phil >Let's be careful here; we are in dire danger of agreeing on something. -- John Larkin Highland Technology, Inc lunatic fringe electronics
Reply by ●October 19, 20192019-10-19
On Saturday, October 19, 2019 at 2:52:45 AM UTC-4, Bill Sloman wrote:> On Friday, October 18, 2019 at 1:05:18 PM UTC+11, George Herold wrote: > > On Thursday, October 17, 2019 at 2:26:10 PM UTC-4, George Herold wrote: > > > On Thursday, October 17, 2019 at 2:01:02 PM UTC-4, John Larkin wrote: > > > > On Thu, 17 Oct 2019 10:17:47 -0700 (PDT), George Herold > > > > <gherold@teachspin.com> wrote: > > > > > > > > >On Thursday, October 17, 2019 at 12:24:20 PM UTC-4, jla...@highlandsniptechnology.com wrote: > > > > >> On Thu, 17 Oct 2019 08:53:25 -0700 (PDT), George Herold > > > > >> <gherold@teachspin.com> wrote: > > > > >> > > > > >> >On Thursday, October 17, 2019 at 11:02:13 AM UTC-4, jla...@highlandsniptechnology.com wrote: > > > > >> >> On Thu, 17 Oct 2019 05:44:51 -0000 (UTC), Steve Wilson <no@spam.com> > > > > >> >> wrote: > > > > >> >> > > > > >> >> >John Larkin <jlarkin@highland_atwork_technology.com> wrote: > > > > >> >> > > > > > >> >> >> Here's possibly the only curve like this ever posted online: > > > > >> >> > > > > > >> >> >> https://www.dropbox.com/s/i4wwttdgqycz9rv/Alum_Leakage_63u.JPG?raw=1 > > > > >> >> > > > > > >> >> >See Fig. 4(b) on Page 2 in > > > > >> >> > > > > > >> >> >https://jianghai-europe.com/wp-content/uploads/8-Jianghai-Europe-E-Cap- > > > > >> >> >Leakage-Current-AAL-2018-09-18.pdf > > > > >> >> > > > > > >> >> >The curves are exponential. > > > > >> >> > > > > >> >> That fig 4b is an obvious made-up cartoon. It's certainly not > > > > >> >> exponential. And it has no numbers. > > > > >> >Ditto on the thanks. > > > > >> >The Tardin article mentions that the caps behave like they have a > > > > >> >zener diode in parallel... So having the current look like noisy > > > > >> >zener current above the 'threshold' makes some sense. > > > > >> > > > > > >> >Years ago I charge an Al eletro to ~1/2 the max voltage, left it > > > > >> >on my bench for the weekend and came back to see the voltage had > > > > >> >only dropped by ~10% or so. It would be fun to hook one up > > > > >> >to an electrometer and let it sit there for a week or whatever > > > > >> >and record the voltage. > > > > >> > > > > > >> >George H. > > > > >> > > > > >> Or just check it with a DVM now and then. I did that with a supercap > > > > >> for a few months. > > > > >Right... I think I used the trick of putting a Gig ohm in series > > > > >with my DMM and dividing by 100. > > > > >I'd bet it can't be exponential* 'all the way down' at some point there'll be some other constant (resistive) leakage path. > > > > > > > > > >Hey are tant's any better than Al-electros. At my ppoe I made this > > > > >triangle wave generator, current source into a cap, milli second to > > > > >kilo second periods. I used a 100uF tant for the longest times... > > > > >seemed to work fine.. but I only 'really' measured the longest times > > > > >once. (otherwise just made sure it went up and down.) > > > > > > > > > >George H. > > > > >*does exponential imply some thermal mechanism? > > > > > > > > A pure RC has a exponential decay, e^(-kt). But the leakage in an > > > > electrolytic isn't ohmic, so the decay slows down as the voltage > > > > drops. > > > > > > > > Pretty complex. > > > Right, if you monitor the voltage you'd have to integrate it to get the > > > current.. It's not at all clear to me what that double exponential > > > would look like. > > > > > > George H. > > > something like this? > > > https://en.wikipedia.org/wiki/Double_exponential_function > > > That doesn't seem right. > > > > If, > > I(t) = Io*exp(V(t)/Vx) = C dV/dt > > where Io, Vx and C are constants > > > > Then I get that > > V(t) = Vx * ln{(C*Vx)/(Io*t)}.. but I might have made a mistake, > > and getting the initial conditions right is a bit.. uncertain. > > > > I need a good graphing program. Time to learn python? > > Excel isn't a good graphing program, but you can get it to produce graphs. >Excel is my least favorite program ever... the graphs are particularly bad.. but the rest too.> IIRR Mathcad and Scicad can do it too.Sure but I liked python.. it's interpreted like basic, I really like that when for looking for my mistakes. George H.> > -- > Bill Sloman, Sydney
Reply by ●October 19, 20192019-10-19
On Saturday, October 19, 2019 at 10:38:44 AM UTC-4, jla...@highlandsniptechnology.com wrote:> On Sat, 19 Oct 2019 07:48:13 -0000 (UTC), Steve Wilson <no@spam.com> > wrote: > > >John Larkin <jlarkin@highland_atwork_technology.com> wrote: > > > >> On Thu, 17 Oct 2019 20:45:36 -0000 (UTC), Steve Wilson <no@spam.com> > >> wrote: > > > >>>John Larkin <jlarkin@highland_atwork_technology.com> wrote: > > > >>>> On Thu, 17 Oct 2019 17:13:40 -0000 (UTC), Steve Wilson <no@spam.com> > >>>> wrote: > > > >>>>>jlarkin@highlandsniptechnology.com wrote: > > > >>>>>> Quite welcome. It's good to have some real numbers on (one) real > >>>>>> cap. > > > >>>>>Yor data is valid for that capacitor only. > > > >>>> Excellent whining. > > > >>>> It's more data than data on no capacitors. I suspect that all wet > >>>> aluminum electros will have similar shaped curves, so will be > >>>> self-stabilizing in series strings. > > > >>>Why suspect? Why not read some of the links I provided? For example, see > >>>Page 3 of > > > >>>https://jianghai-europe.com/wp-content/uploads/8-Jianghai-Europe-E-Cap- > >>>Leakage-Current-AAL-2018-09-18.pdf > > > >>>Quote: > > > >>>The operating leakage current [5] as a measure of the forming condition > >>>of anode foil depends on the time, applied voltage, temperature, and > >>>history of the capacitor (fig. 4 (a) ~ (c)). Typical values of the > >>>operational leakage current range between approx. 5 ~ 15% of the data > >>>sheet value of leakage current amount and are usually reached after > >>>several ten minutes of continuous operation. > > > >>>The leakage current specified in the data sheet shall be valid even > >>>after a long, voltage-free storage period and has therefore a much > >>>higher numerical value than the operating leakage current. The oxide > >>>layer dissolves to a certain extent as a function of temperature and > >>>electrolyte composition, because without any voltage applied, the oxide > >>>layer cannot regenerate ("self-healing") [5]. > > > >>>While low-voltage capacitors (up to 100 V rated voltage) with > >>>solvent-based electrolyte systems are usually very stable, high-voltage > >>>capacitors (from 160 V rated voltage) with ethylene glycole-based > >>>electrolytes and in particular so-called "low ESR" types with aqueous > >>>electrolytes may exhibit an increase of leakage currents throughout > >>>their lifetime. > > > >>>15 ~ 30 minutes of operation of the electrolytic capacitors via a > >>>resistor (low-voltage: 100 Ohm, high-voltage: 1 k, see [7], section 4.1 > >>>"pretreatment") at a voltage increased gradually to rated voltage may > >>>heal the weak spots in the dielectric and lower the leakage current > >>>below the data sheet value. > > > >>>>>Every cap will be different. There are many different electrolytes > >>>>>with different characteristics, such as non-solid borax or organic, > >>>>>non-solid water-based, solid manganese dioxide, solid conducting > >>>>>polymer, non-solid hybrid electrolyte, etc., and the leakage > >>>>>characteristics will be different for each type. See Wikipedia, > >>>>>"Aluminum electrolytic capacitor", at > > > >>>>>https://en.wikipedia.org/wiki/Aluminum_electrolytic_capacitor > > > >>>> Superb, well-researched whining. > > > >>>> I used a standard Panasonic aluminum electrolytic. > > > >>>> Measure something else and post it here. > > > >>>You are trying to pretend the measurement you made on one capacitor is > >>>the first time such a measurement has been made. In fact, you said so > >>>yourself. > > > >> I said "possibly" the only one available online, after several minutes > >> of intense web searching. If you can find an electrolytic cap leakage > >> measurement, past rated voltage, with real numbers, not fuzzy > >> cartoons, please post the link for us. > > > >Why measure past the rated voltage? You are never going to operate there. > >You simply risk damaging the capacitor for no good reason. > > The issue was series strings of electrolytic caps, where the total > supply voltage is more than the rated voltage of the caps. Film caps > can blow up in that situation. What do lytics do? > > Answer: their IV curves make them safely self-equalize. > > > > >The curve shown in fig. 4 is a generic curve. The actual curves are > >different for each capacitor, and depend on variables such as those > >described above. So it is impossible to represent all capacitors at once. > > > >>>I posted numerous links that show your assumption is not valid. > > > >> I didn't assume anything. I measured something. > > > >Your data is meaningless. As mentioned elsewhere, capacitor manufacturers > >can give actual curves for their capacitors. > > Post a link of leakage past rated voltage. Real data, not faked > cartoons. > > > You can compare your data > >against the spec to see if your cap is out of spec. > > > >> Try it; it's more fun than cutting and pasting a lot of text. > > > >Your data is meaningless. > > Since you probably don't design electronics, it is meaningless to you. > > > > >> There is a > >>>tremendous amout of knowlege in those links. > > > >> Lotta words, no numbers. Engineers need numbers. > > > >Nah. Real engineers need equations. Do an exponential fit to your data. The > >Stdev will give an indication of the quality of the measurement. The > >equation will allow you to compare other capacitors. The curve can be > >compared to actual specs from manufacturers. > > > >You need to also try measuring the capacitor voltage with a constant > >current source. That could give valuable new information. > > How would that be different? You'd get the same data points, just > slower.I just want to say, that when people tell me *not* to measure parts above and beyond the specs.. The more I want too. :^) I've had 36V opamps running up around 48V for a while... many minutes. How do you test some power supply but to load it and see how it fails* George H. *I'm saying a little thank you to all the parts gave up theirs lives so I might know their limits.> > > > > > -- > > John Larkin Highland Technology, Inc > > lunatic fringe electronics
