10V ceramic cap at 95V DC ?
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From: Joerg on 2 Apr 2007 14:42 Ian wrote: > "Adam S" <not.valid(a)nosuchaddress> wrote in message > news:460f8f69$0$9771$afc38c87(a)news.optusnet.com.au... > >>I was wondering what happens when you put too much voltage across a one of >>those low voltage multilayer ceramic capacitors. I took a 2.2uF 10V X7R in >>1206 package, and applied 95V across it and nothing exciting happened. >>Leakage settled to 0.5uA after 2 minutes. Even after disconnecting for 1 >>minute the terminal voltage was around 60V+. The only thing I noticed was >>capacitance had dropped from 2.30uF to 1.85uF (at 0 VDC bias) after the >>test. However heating the capacitor with a soldering iron tip for a second >>, had restored it to its original 2.30uF. >> >>So what bad things are suppose to happen when you exceed the 10V spec. ? > > > ISTR some information (AVX site?) saying that most ceramic caps will > survive several times the rated voltage, it is just that a few per batch may > not. > Sounds like Russian roulette ;-) -- Regards, Joerg http://www.analogconsultants.com
From: Adam S on 2 Apr 2007 17:13 Ian wrote: > "Adam S" <not.valid(a)nosuchaddress> wrote in message > news:460f8f69$0$9771$afc38c87(a)news.optusnet.com.au... >> I was wondering what happens when you put too much voltage across a one of >> those low voltage multilayer ceramic capacitors. I took a 2.2uF 10V X7R in >> 1206 package, and applied 95V across it and nothing exciting happened. >> Leakage settled to 0.5uA after 2 minutes. Even after disconnecting for 1 >> minute the terminal voltage was around 60V+. The only thing I noticed was >> capacitance had dropped from 2.30uF to 1.85uF (at 0 VDC bias) after the >> test. However heating the capacitor with a soldering iron tip for a second >> , had restored it to its original 2.30uF. >> >> So what bad things are suppose to happen when you exceed the 10V spec. ? > > ISTR some information (AVX site?) saying that most ceramic caps will > survive several times the rated voltage, it is just that a few per batch may > not. I only tested a couple of caps and didn't go higher that 95V on a 10V rated device. Its interesting watching such a tiny thing make a nice little blue spark when shorted.
From: Tim Williams on 2 Apr 2007 18:39 Hmmmmm. Methinks I want to buy a reel of a thousand, build an automatic testing machine, and assemble the remaining ones (being made almost entirely of magic smoke, the bad ones remove themselves from the machine with the assistance of a small fan) into a rather large capacitor. Whaddya think, energy density comparable to aluminum electrolytic at least? ;o) Power density through the roof! Tim -- "Librarians are hiding something." - Steven Colbert Website @ http://webpages.charter.net/dawill/tmoranwms "Ian" <ian_bucknerNOT(a)agilent.com> wrote in message news:1175516282.980507(a)newsreg.cos.agilent.com... > > "Adam S" <not.valid(a)nosuchaddress> wrote in message > news:460f8f69$0$9771$afc38c87(a)news.optusnet.com.au... > >I was wondering what happens when you put too much voltage across a one of > >those low voltage multilayer ceramic capacitors. I took a 2.2uF 10V X7R in > >1206 package, and applied 95V across it and nothing exciting happened. > >Leakage settled to 0.5uA after 2 minutes. Even after disconnecting for 1 > >minute the terminal voltage was around 60V+. The only thing I noticed was > >capacitance had dropped from 2.30uF to 1.85uF (at 0 VDC bias) after the > >test. However heating the capacitor with a soldering iron tip for a second > >, had restored it to its original 2.30uF. > > > > So what bad things are suppose to happen when you exceed the 10V spec. ? > > ISTR some information (AVX site?) saying that most ceramic caps will > survive several times the rated voltage, it is just that a few per batch may > not. > > Regards > Ian > >
From: Rich Grise on 3 Apr 2007 13:40 On Mon, 02 Apr 2007 17:39:23 -0500, Tim Williams wrote: [top-post repaired, see below] > "Ian" <ian_bucknerNOT(a)agilent.com> wrote in message >> "Adam S" <not.valid(a)nosuchaddress> wrote in message >> >I was wondering what happens when you put too much voltage across a one > of >> >those low voltage multilayer ceramic capacitors. I took a 2.2uF 10V X7R .... >> > So what bad things are suppose to happen when you exceed the 10V >> > spec. ? >> >> ISTR some information (AVX site?) saying that most ceramic caps will >> survive several times the rated voltage, it is just that a few per >> batch may not. > Hmmmmm. Methinks I want to buy a reel of a thousand, build an automatic > testing machine, and assemble the remaining ones (being made almost entirely > of magic smoke, the bad ones remove themselves from the machine with the > assistance of a small fan) into a rather large capacitor. Whaddya think, > energy density comparable to aluminum electrolytic at least? ;o) Power > density through the roof! If you've got the money, I've got the time! ;-) Good Luck! Rich
From: Tim Williams on 3 Apr 2007 17:08 "Rich Grise" <rich(a)example.net> wrote in message news:pan.2007.04.03.18.41.17.638585(a)example.net... > If you've got the money, I've got the time! ;-) College student :-( Tim -- "Librarians are hiding something." - Steven Colbert Website @ http://webpages.charter.net/dawill/tmoranwms
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