What caused the high temperature?

"Randy Poe" . wrote in message

news:1195056350.843348.184250@o3g2000hsb.googlegroups.com...

On Nov 14, 10:52 am, "Unknown" <unkn...@unknown.kom> wrote:

> How do you dream up all these ridiculous things?"M.I.5¾"

> <no....@no.where.NO_SPAM.co.uk> wrote in message

>

> news:473aab1e$1_1@glkas0286.greenlnk.net...

>

>

>

> > "Unknown" <unkn...@unknown.kom> wrote in message

> >news:SVj_i.68355$YL5.45228@newssvr29.news.prodigy.net...

> >> What type of capacitor has to cool off before it accepts a charge?

>

> > A: A faulty one.

>

> > It is well a known problem particularly among certain types of

> > electrolytic capacitors. The usual problem is that the EPR (Effective

> > parallel resistance) of the capacitor falls alarmingly as it warms up

> > rendering it ineffective as a capacitor.

 

Two charts of electrolytic capacitor failure modes. Check out

Table 2 here:

http://industrial.panasonic.com/www-data/pdf/ABA0000/ABA0000TE4.pdf

 

Operating at high temperature is shown to cause failure

by increase in leakage current.

 

or Figure 2.10 here:

http://etd.gatech.edu/theses/available/etd-04082007-083102/unrestricted/imam_afroz_m_200705_phd.pdf

 

Operating at high temperature is shown to cause failure

by loss of effective resistance (i.e. increased leakage).

 

- Randy

On Nov 14, 12:39 pm, "Unknown" <unkn...@unknown.kom> wrote:

> What caused the high temperature?

 

Being in a hot place.

 

- Randy

Then the failure occurred BEFORE the capacitor went bad.

"Randy Poe" . wrote in message

news:1195063669.503182.210110@o38g2000hse.googlegroups.com...

> On Nov 14, 12:39 pm, "Unknown" <unkn...@unknown.kom> wrote:

>> What caused the high temperature?

>

> Being in a hot place.

>

> - Randy

>

On Nov 14, 2:56 pm, "Unknown" <unkn...@unknown.kom> wrote:

> news:1195063669.503182.210110@o38g2000hse.googlegroups.com...

>

> > On Nov 14, 12:39 pm, "Unknown" <unkn...@unknown.kom> wrote:

> >> What caused the high temperature?

>

> > Being in a hot place.

>

> Then the failure occurred BEFORE the capacitor went bad.

> "Randy Poe" . wrote in message

>

 

Um, what? You mean just the fact that I *try* to

operate a capacitor in a poorly air-conditioned room

implies it has failed?

 

Or do you mean that just the fact that the temperature

around my circuit board is above room temperature

implies that something has failed?

 

Or what?

 

- Randy

On Wed, 14 Nov 2007 10:07:49 -0800, Randy Poe .

wrote:

>On Nov 14, 12:39 pm, "Unknown" <unkn...@unknown.kom> wrote:

>> What caused the high temperature?

>

>Being in a hot place.

>

> - Randy

 

 

It would have to be pretty hot of at least above 120F tho I've seen

some hardware listed in the 140's F as maximum. My guess is the 2nd

applies here. Now the problem is what causes the high temperature to

begin with?? I have doubts about a bad fan but perhaps or maybe a

short circuit????

On Nov 14, 3:25 pm, RnR <rnrte...@gmail.com> wrote:

> On Wed, 14 Nov 2007 10:07:49 -0800, Randy Poe .

> wrote:

>

> >On Nov 14, 12:39 pm, "Unknown" <unkn...@unknown.kom> wrote:

> >> What caused the high temperature?

>

> >Being in a hot place.

>

> > - Randy

>

> It would have to be pretty hot of at least above 120F tho I've seen

> some hardware listed in the 140's F as maximum. My guess is the 2nd

> applies here. Now the problem is what causes the high temperature to

> begin with?? I have doubts about a bad fan but perhaps or maybe a

> short circuit????

 

This all seems incidental to the discussion. There was

doubt raised on the point that high temperatures could

cause failure of electrolytic capacitors. Let's say that

the high temperature is out of spec for the board. Let's

say that something else HAS failed. How does that

bear on the discussion of this failure mode for capacitors

exposed to high temperatures and whether or not it's

a "ridiculous thing" to say that high temperatures will cause

this effect on electrolytic capacitors?

 

- Randy

"Randy Poe" . wrote in message

news:1195070508.810308.286150@k79g2000hse.googlegroups.com...

: On Nov 14, 2:56 pm, "Unknown" <unkn...@unknown.kom> wrote:

: > news:1195063669.503182.210110@o38g2000hse.googlegroups.com...

: >

: > > On Nov 14, 12:39 pm, "Unknown" <unkn...@unknown.kom> wrote:

: > >> What caused the high temperature?

: >

: > > Being in a hot place.

: >

: > Then the failure occurred BEFORE the capacitor went bad.

: > "Randy Poe" . wrote in message

: >

:

: Um, what? You mean just the fact that I *try* to

: operate a capacitor in a poorly air-conditioned room

: implies it has failed?

 

It is your claim that the failure has an environmental cause.

Do not operate capacitors in a poorly air-conditioned room,

they will fail (according to Poe). Um, yes.

"Randy Poe" . wrote in message

news:1195072605.103099.174990@v2g2000hsf.googlegroups.com...

: On Nov 14, 3:25 pm, RnR <rnrte...@gmail.com> wrote:

: > On Wed, 14 Nov 2007 10:07:49 -0800, Randy Poe .

: > wrote:

: >

: > >On Nov 14, 12:39 pm, "Unknown" <unkn...@unknown.kom> wrote:

: > >> What caused the high temperature?

: >

: > >Being in a hot place.

: >

: > > - Randy

: >

: > It would have to be pretty hot of at least above 120F tho I've seen

: > some hardware listed in the 140's F as maximum. My guess is the 2nd

: > applies here. Now the problem is what causes the high temperature to

: > begin with?? I have doubts about a bad fan but perhaps or maybe a

: > short circuit????

:

: This all seems incidental to the discussion.

 

Bullshit, it is your claim that capacitor failure has an environmental

cause, that is most pertinent to the discussion you contributed to.

On Nov 14, 2:56 pm, "Unknown" <unkn...@unknown.kom> wrote:

> Then the failure occurred BEFORE the capacitor went bad.

 

Temperature has what relevance to the problem? Unfortunately, many

want to blame temperature when other functions are not understood.

 

Computers must work just fine even when room temperature is above

100 degree F. In fact, testing a computer in a 100 degree room is one

way to find defects because the defect results in failure.

 

Electrolytic capacitors inside power supplies are typically rated

for higher temperatures. One failure mode is Effective Series

Resistance or ESR (not Parallel Resistance). If chemistry inside the

electrolytic is failing, then series resistance increases. Higher

resistance means capacitor gets hotter - a feedback cycle that

eventually causes capacitor failure.

 

But this is not relevant to a power supply operating on 240 volts AC

when the power supply is rated for 240 volts.

 

Electrolytic failure is most often a manufacturing defect inside the

capacitor or excessive voltage applied to that capacitor. Capacitors

are routinely selected to withstand temperatures well above standard

room temperature. Its temperature rating is usually printed on that

electrolytic. Long before accepting what was posted, view those

numbers yourself.

"Androcles" <Engineer@hogwarts.physics_> wrote in message

news:HXE_i.126189$vI1.83585@fe1.news.blueyonder.co.uk...

> Sounds like a short circuit to me. Perhaps he's connecting

> them with the wrong polarity of the "certain type".

>

 

It's not a short circuit as such, just a lower resistance in parallel with

the capacitor. It's enough to prevent the switching circuit from switching.

> "Unknown" <unknown@unknown.kom> wrote in message

> news:nRE_i.18302$4V6.9037@newssvr14.news.prodigy.net...

> : How do you dream up all these ridiculous things?

> : "M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message

> : news:473aab1e$1_1@glkas0286.greenlnk.net...

> : >

> : > "Unknown" <unknown@unknown.kom> wrote in message

> : > news:SVj_i.68355$YL5.45228@newssvr29.news.prodigy.net...

> : >> What type of capacitor has to cool off before it accepts a charge?

> : >

> : > A: A faulty one.

> : >

> : > It is well a known problem particularly among certain types of

> : > electrolytic capacitors. The usual problem is that the EPR (Effective

> : > parallel resistance) of the capacitor falls alarmingly as it warms up

> : > rendering it ineffective as a capacitor.

> : >

> : >

> : >

> :

> :

>

>

"Randy Poe" . wrote in message

news:1195056350.843348.184250@o3g2000hsb.googlegroups.com...

On Nov 14, 10:52 am, "Unknown" <unkn...@unknown.kom> wrote:

> How do you dream up all these ridiculous things?"M.I.5¾"

> <no....@no.where.NO_SPAM.co.uk> wrote in message

>

> news:473aab1e$1_1@glkas0286.greenlnk.net...

>

>

>

> > "Unknown" <unkn...@unknown.kom> wrote in message

> >news:SVj_i.68355$YL5.45228@newssvr29.news.prodigy.net...

> >> What type of capacitor has to cool off before it accepts a charge?

>

> > A: A faulty one.

>

> > It is well a known problem particularly among certain types of

> > electrolytic capacitors. The usual problem is that the EPR (Effective

> > parallel resistance) of the capacitor falls alarmingly as it warms up

> > rendering it ineffective as a capacitor.

 

Two charts of electrolytic capacitor failure modes. Check out

Table 2 here:

http://industrial.panasonic.com/www-data/pdf/ABA0000/ABA0000TE4.pdf

 

Operating at high temperature is shown to cause failure

by increase in leakage current.

 

or Figure 2.10 here:

http://etd.gatech.edu/theses/available/etd-04082007-083102/unrestricted/imam_afroz_m_200705_phd.pdf

 

Operating at high temperature is shown to cause failure

by loss of effective resistance (i.e. increased leakage).

 

-----------

 

Indeed. In general electrolytic capacitors are rated at either 85°C or

105°C. The former is obviously cheaper than the latter and that's often

what gets used as such supplies don't run that warm. However, even if

operated below 85°C, the former type are considerably more unreliable than

the latter.

"Unknown" <unknown@unknown.kom> wrote in message

news:nRE_i.18302$4V6.9037@newssvr14.news.prodigy.net...

> How do you dream up all these ridiculous things?

 

Apparently well to known to nearly everyone - but not you.

> "M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message

> news:473aab1e$1_1@glkas0286.greenlnk.net...

>>

>> "Unknown" <unknown@unknown.kom> wrote in message

>> news:SVj_i.68355$YL5.45228@newssvr29.news.prodigy.net...

>>> What type of capacitor has to cool off before it accepts a charge?

>>

>> A: A faulty one.

>>

>> It is well a known problem particularly among certain types of

>> electrolytic capacitors. The usual problem is that the EPR (Effective

>> parallel resistance) of the capacitor falls alarmingly as it warms up

>> rendering it ineffective as a capacitor.

>>

>>

>>

>

>

"M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message

news:473bf819$1_1@glkas0286.greenlnk.net...

:

: "Androcles" <Engineer@hogwarts.physics_> wrote in message

: news:HXE_i.126189$vI1.83585@fe1.news.blueyonder.co.uk...

: > Sounds like a short circuit to me. Perhaps he's connecting

: > them with the wrong polarity of the "certain type".

: >

:

: It's not a short circuit as such, just a lower resistance in parallel

 

If you connect a copper wire or a solder splash across the cap

you'd be connecting a lower resistance in parallel, even copper

wire has some resistance. That's a short circuit by definition.

"w_tom" <w_tom1@usa.net> wrote in message

news:07825db1-85a6-4c24-aac4-e70825cdea78@w34g2000hsg.googlegroups.com...

> On Nov 14, 2:56 pm, "Unknown" <unkn...@unknown.kom> wrote:

>> Then the failure occurred BEFORE the capacitor went bad.

>

> Temperature has what relevance to the problem? Unfortunately, many

> want to blame temperature when other functions are not understood.

>

> Computers must work just fine even when room temperature is above

> 100 degree F. In fact, testing a computer in a 100 degree room is one

> way to find defects because the defect results in failure.

>

> Electrolytic capacitors inside power supplies are typically rated

> for higher temperatures. One failure mode is Effective Series

> Resistance or ESR (not Parallel Resistance). If chemistry inside the

> electrolytic is failing, then series resistance increases. Higher

> resistance means capacitor gets hotter - a feedback cycle that

> eventually causes capacitor failure.

>

 

Both ESR and EPR are present in every capacitor made. ESR is usually quoted

on spec sheets because every capacitor has this built in (it's a fact of the

way they are designed). EPR, hopefully is not present to any extent that

affects the operation of the capacitor. Although the ESR can rise, it is

not a particularly common failure mode and is usually more due to mechanical

construction than chemistry.

> But this is not relevant to a power supply operating on 240 volts AC

> when the power supply is rated for 240 volts.

>

 

On the contrary, it is relevant to any circuit using capacitors.

> Electrolytic failure is most often a manufacturing defect inside the

> capacitor or excessive voltage applied to that capacitor. Capacitors

> are routinely selected to withstand temperatures well above standard

> room temperature. Its temperature rating is usually printed on that

> electrolytic. Long before accepting what was posted, view those

> numbers yourself.

>

 

All capacitor made are not equal - it's a fact of manufacturing. About half

the capacitors will work better than they were designed to, and the other

half will not work as well. A few will have manufacturing features that

lead to some failure mode or other. An increase in the leakage (or a

reduction in the EPR) is but one such mode of failure (but the most common,

at least among electrolytic capacitors). In general, once the capacitor

starts to leak excessively, the leakage will get worse as time progresses.

It is a temperature dependant phenomenon.

 

It is of course possible to manufacture capacitors that conform more closely

to the intended design and have far fewer examples of failure (and indeed

such are made). However, if they were used to build computer power

supplies, nobody would be able to afford them. It's all a compromise

between reliability and cost.

"M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message

news:473bf94a$1_1@glkas0286.greenlnk.net...

:

: "Randy Poe" . wrote in message

: news:1195056350.843348.184250@o3g2000hsb.googlegroups.com...

: On Nov 14, 10:52 am, "Unknown" <unkn...@unknown.kom> wrote:

: > How do you dream up all these ridiculous things?"M.I.5¾"

: > <no....@no.where.NO_SPAM.co.uk> wrote in message

: >

: > news:473aab1e$1_1@glkas0286.greenlnk.net...

: >

: >

: >

: > > "Unknown" <unkn...@unknown.kom> wrote in message

: > >news:SVj_i.68355$YL5.45228@newssvr29.news.prodigy.net...

: > >> What type of capacitor has to cool off before it accepts a charge?

: >

: > > A: A faulty one.

: >

: > > It is well a known problem particularly among certain types of

: > > electrolytic capacitors. The usual problem is that the EPR (Effective

: > > parallel resistance) of the capacitor falls alarmingly as it warms up

: > > rendering it ineffective as a capacitor.

:

: Two charts of electrolytic capacitor failure modes. Check out

: Table 2 here:

: http://industrial.panasonic.com/www-data/pdf/ABA0000/ABA0000TE4.pdf

:

: Operating at high temperature is shown to cause failure

: by increase in leakage current.

:

: or Figure 2.10 here:

:

http://etd.gatech.edu/theses/available/etd-04082007-083102/unrestricted/imam_afroz_m_200705_phd.pdf

:

: Operating at high temperature is shown to cause failure

: by loss of effective resistance (i.e. increased leakage).

:

: -----------

:

: Indeed. In general electrolytic capacitors are rated at either 85°C or

: 105°C. The former is obviously cheaper than the latter and that's often

: what gets used as such supplies don't run that warm. However, even if

: operated below 85°C, the former type are considerably more unreliable than

: the latter.

 

Oh, so the latter break down at temperatures below 85°C because

they are less reliable than the former cheaper ones... very logical.

"RnR" <rnrtexas@gmail.com> wrote in message

news:q0mmj3ttpsm2mvkvqjvgvt40g7dufgt2q6@4ax.com...

> On Wed, 14 Nov 2007 10:07:49 -0800, Randy Poe .

> wrote:

>

>>On Nov 14, 12:39 pm, "Unknown" <unkn...@unknown.kom> wrote:

>>> What caused the high temperature?

>>

>>Being in a hot place.

>>

>> - Randy

>

>

> It would have to be pretty hot of at least above 120F tho I've seen

> some hardware listed in the 140's F as maximum. My guess is the 2nd

> applies here. Now the problem is what causes the high temperature to

> begin with?? I have doubts about a bad fan but perhaps or maybe a

> short circuit????

 

The particular temperatures we are talking here are not unusual

temperatures, but the usual temperature excursions experienced by components

in any circuit while it is operating. Any operating circuit has current

flowing in its parts and this generates heat. The capacitors we are

concerned with are not experiencing heat outside of their design range, but

rather the capacitors are unable tolerate even this design heat because of

adverse manufacturing tolerances or possibly even that he capacitor has been

subject to a transient event that has reduced its ability to withstand such

heat (for example a voltage spike that partially breaks down the dielectric

layer).

BS

"M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message

news:473bf988$1_1@glkas0286.greenlnk.net...

>

> "Unknown" <unknown@unknown.kom> wrote in message

> news:nRE_i.18302$4V6.9037@newssvr14.news.prodigy.net...

>> How do you dream up all these ridiculous things?

>

> Apparently well to known to nearly everyone - but not you.

>

>> "M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message

>> news:473aab1e$1_1@glkas0286.greenlnk.net...

>>>

>>> "Unknown" <unknown@unknown.kom> wrote in message

>>> news:SVj_i.68355$YL5.45228@newssvr29.news.prodigy.net...

>>>> What type of capacitor has to cool off before it accepts a charge?

>>>

>>> A: A faulty one.

>>>

>>> It is well a known problem particularly among certain types of

>>> electrolytic capacitors. The usual problem is that the EPR (Effective

>>> parallel resistance) of the capacitor falls alarmingly as it warms up

>>> rendering it ineffective as a capacitor.

>>>

>>>

>>>

>>

>>

>

>

On Nov 15, 3:23 am, "M.I.5 3/4" <no....@no.where.NO_SPAM.co.uk> wrote:

> All capacitor made are not equal - it's a fact of manufacturing. About half

> the capacitors will work better than they were designed to, and the other

> half will not work as well.

 

Not quite correct. Almost all work at least as good as they were

designed for. Some will work far better. Cofidence levels - all

capacitors must at least meet specs - what they are intended to do.

 

The primary source of heating is ESR. ESR increases as the capactor

fails causing even more heat. And all that is completely irrelevant

to the OPs question. That computer must work just fine even when the

70 degree room rises to above 100 degree F. Again, what is the

temperature printed on that capacitor's label?

"Androcles" <Engineer@hogwarts.physics_> wrote in message

news:%7T_i.74198$7_4.66526@fe3.news.blueyonder.co.uk...

>

> "M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message

> news:473bf819$1_1@glkas0286.greenlnk.net...

> :

> : "Androcles" <Engineer@hogwarts.physics_> wrote in message

> : news:HXE_i.126189$vI1.83585@fe1.news.blueyonder.co.uk...

> : > Sounds like a short circuit to me. Perhaps he's connecting

> : > them with the wrong polarity of the "certain type".

> : >

> :

> : It's not a short circuit as such, just a lower resistance in parallel

>

> If you connect a copper wire or a solder splash across the cap

> you'd be connecting a lower resistance in parallel, even copper

> wire has some resistance. That's a short circuit by definition.

>

 

So?

 

I doubt that the OP has done that.

"w_tom" <w_tom1@usa.net> wrote in message

news:bd393d88-9656-4399-949b-ebb7a230e3a7@v4g2000hsf.googlegroups.com...

> On Nov 15, 3:23 am, "M.I.5 3/4" <no....@no.where.NO_SPAM.co.uk> wrote:

>> All capacitor made are not equal - it's a fact of manufacturing. About

>> half

>> the capacitors will work better than they were designed to, and the other

>> half will not work as well.

>

> Not quite correct. Almost all work at least as good as they were

> designed for. Some will work far better. Cofidence levels - all

> capacitors must at least meet specs - what they are intended to do.

>

 

You really don't know anything do you?

 

Capacitors are produced is such large quantities that the conformance to

specification is done by testing a sample of each batch only. It is a

fundamental requirement of sample testing that you have to accept that items

that do not conform to specification will be accepted. If you cannot accept

that then you can't do sample testing. Also, if you have a look at any

sample testing tables, you will see that in most of them failures are

allowed, but the batch can still be accepted. There are tables that allow

no failures, but that does not prevent failures from occuring in the

majority (untested) part of the batch.

 

The BS6001 series of standards would be a good starting point.

> The primary source of heating is ESR. ESR increases as the capactor

> fails causing even more heat. And all that is completely irrelevant

> to the OPs question. That computer must work just fine even when the

> 70 degree room rises to above 100 degree F.

 

ESR is but one source of heating and usually (or should be) the most

insignificant. The primary sources of heating are all the heat disipating

components around the capacitor. ESR does not necessarily increase as the

capacitor fails, but a reduced EPR can also be a source of internally

generated heat, but only if the rest of the circuit permits enough current

to flow for it to become a factor.

>Again, what is the temperature printed on that capacitor's label?

 

I have already addressed this point. Try reading the rest of the thread.

"Androcles" <Engineer@hogwarts.physics_> wrote in message

news:ZqT_i.74295$7_4.7509@fe3.news.blueyonder.co.uk...

>

> "M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message

> news:473bf94a$1_1@glkas0286.greenlnk.net...

> :

> : "Randy Poe" . wrote in message

> : news:1195056350.843348.184250@o3g2000hsb.googlegroups.com...

> : On Nov 14, 10:52 am, "Unknown" <unkn...@unknown.kom> wrote:

> : > How do you dream up all these ridiculous things?"M.I.5¾"

> : > <no....@no.where.NO_SPAM.co.uk> wrote in message

> : >

> : > news:473aab1e$1_1@glkas0286.greenlnk.net...

> : >

> : >

> : >

> : > > "Unknown" <unkn...@unknown.kom> wrote in message

> : > >news:SVj_i.68355$YL5.45228@newssvr29.news.prodigy.net...

> : > >> What type of capacitor has to cool off before it accepts a charge?

> : >

> : > > A: A faulty one.

> : >

> : > > It is well a known problem particularly among certain types of

> : > > electrolytic capacitors. The usual problem is that the EPR

> (Effective

> : > > parallel resistance) of the capacitor falls alarmingly as it warms

> up

> : > > rendering it ineffective as a capacitor.

> :

> : Two charts of electrolytic capacitor failure modes. Check out

> : Table 2 here:

> : http://industrial.panasonic.com/www-data/pdf/ABA0000/ABA0000TE4.pdf

> :

> : Operating at high temperature is shown to cause failure

> : by increase in leakage current.

> :

> : or Figure 2.10 here:

> :

> http://etd.gatech.edu/theses/available/etd-04082007-083102/unrestricted/imam_afroz_m_200705_phd.pdf

> :

> : Operating at high temperature is shown to cause failure

> : by loss of effective resistance (i.e. increased leakage).

> :

> : -----------

> :

> : Indeed. In general electrolytic capacitors are rated at either 85°C or

> : 105°C. The former is obviously cheaper than the latter and that's often

> : what gets used as such supplies don't run that warm. However, even if

> : operated below 85°C, the former type are considerably more unreliable

> than

> : the latter.

>

> Oh, so the latter break down at temperatures below 85°C because

> they are less reliable than the former cheaper ones... very logical.

>

 

How you managed to arrive at that conclusion is anyone's guess.

"M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message

news:473d4cc0$1_1@glkas0286.greenlnk.net...

:

: "Androcles" <Engineer@hogwarts.physics_> wrote in message

: news:%7T_i.74198$7_4.66526@fe3.news.blueyonder.co.uk...

: >

: > "M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message

: > news:473bf819$1_1@glkas0286.greenlnk.net...

: > :

: > : "Androcles" <Engineer@hogwarts.physics_> wrote in message

: > : news:HXE_i.126189$vI1.83585@fe1.news.blueyonder.co.uk...

: > : > Sounds like a short circuit to me. Perhaps he's connecting

: > : > them with the wrong polarity of the "certain type".

: > : >

: > :

: > : It's not a short circuit as such, just a lower resistance in parallel

: >

: > If you connect a copper wire or a solder splash across the cap

: > you'd be connecting a lower resistance in parallel, even copper

: > wire has some resistance. That's a short circuit by definition.

: >

:

: So?

 

So it is a short circuit of "the certain type" "as such", contrary to your

hand-waving waffle. What's the 5¾ for? Not your hat size, surely?

"M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message

news:473d500f$1_1@glkas0286.greenlnk.net...

:

: "w_tom" <w_tom1@usa.net> wrote in message

: news:bd393d88-9656-4399-949b-ebb7a230e3a7@v4g2000hsf.googlegroups.com...

: > On Nov 15, 3:23 am, "M.I.5 3/4" <no....@no.where.NO_SPAM.co.uk> wrote:

: >> All capacitor made are not equal - it's a fact of manufacturing. About

: >> half

: >> the capacitors will work better than they were designed to, and the

other

: >> half will not work as well.

: >

: > Not quite correct. Almost all work at least as good as they were

: > designed for. Some will work far better. Cofidence levels - all

: > capacitors must at least meet specs - what they are intended to do.

: >

:

: You really don't know anything do you?

:

: Capacitors are produced is such large quantities that the conformance to

: specification is done by testing a sample of each batch only. It is a

: fundamental requirement of sample testing that you have to accept that

items

: that do not conform to specification will be accepted. If you cannot

accept

: that then you can't do sample testing. Also, if you have a look at any

: sample testing tables,

 

Bwahahahahahah!

You really don't know anything about Quality Control, do you?

 

Do these words mean anything to you: Mean, Variance, Standard Deviation?

 

Tables! Got any sample testing chairs to go with them, size 5¾ ?

HAHAHAHAHAHA!

"M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message

news:473d5093$1_1@glkas0286.greenlnk.net...

:

: "Androcles" <Engineer@hogwarts.physics_> wrote in message

: news:ZqT_i.74295$7_4.7509@fe3.news.blueyonder.co.uk...

: >

: > "M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message

: > news:473bf94a$1_1@glkas0286.greenlnk.net...

: > :

: > : "Randy Poe" . wrote in message

: > : news:1195056350.843348.184250@o3g2000hsb.googlegroups.com...

: > : On Nov 14, 10:52 am, "Unknown" <unkn...@unknown.kom> wrote:

: > : > How do you dream up all these ridiculous things?"M.I.5¾"

: > : > <no....@no.where.NO_SPAM.co.uk> wrote in message

: > : >

: > : > news:473aab1e$1_1@glkas0286.greenlnk.net...

: > : >

: > : >

: > : >

: > : > > "Unknown" <unkn...@unknown.kom> wrote in message

: > : > >news:SVj_i.68355$YL5.45228@newssvr29.news.prodigy.net...

: > : > >> What type of capacitor has to cool off before it accepts a

charge?

: > : >

: > : > > A: A faulty one.

: > : >

: > : > > It is well a known problem particularly among certain types of

: > : > > electrolytic capacitors. The usual problem is that the EPR

: > (Effective

: > : > > parallel resistance) of the capacitor falls alarmingly as it warms

: > up

: > : > > rendering it ineffective as a capacitor.

: > :

: > : Two charts of electrolytic capacitor failure modes. Check out

: > : Table 2 here:

: > : http://industrial.panasonic.com/www-data/pdf/ABA0000/ABA0000TE4.pdf

: > :

: > : Operating at high temperature is shown to cause failure

: > : by increase in leakage current.

: > :

: > : or Figure 2.10 here:

: > :

: >

http://etd.gatech.edu/theses/available/etd-04082007-083102/unrestricted/imam_afroz_m_200705_phd.pdf

: > :

: > : Operating at high temperature is shown to cause failure

: > : by loss of effective resistance (i.e. increased leakage).

: > :

: > : -----------

: > :

: > : Indeed. In general electrolytic capacitors are rated at either 85°C

or

: > : 105°C. The former is obviously cheaper than the latter and that's

often

: > : what gets used as such supplies don't run that warm. However, even if

: > : operated below 85°C, the former type are considerably more unreliable

: > than

: > : the latter.

: >

: > Oh, so the latter break down at temperatures below 85°C because

: > they are less reliable than the former cheaper ones... very logical.

: >

:

: How you managed to arrive at that conclusion is anyone's guess.

 

It's quite simple. Here's a table, you like tables.

 

------------------- Former ------------------ Latter ----------------

< 85°C reliable unreliable

> 85°C unreliable reliable

_____________________________________________

"Androcles" <Engineer@hogwarts.physics_> wrote in message

news:Ure%i.266961$lV4.48700@fe2.news.blueyonder.co.uk...

>

> "M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message

> news:473d500f$1_1@glkas0286.greenlnk.net...

> :

> : "w_tom" <w_tom1@usa.net> wrote in message

> : news:bd393d88-9656-4399-949b-ebb7a230e3a7@v4g2000hsf.googlegroups.com...

> : > On Nov 15, 3:23 am, "M.I.5 3/4" <no....@no.where.NO_SPAM.co.uk> wrote:

> : >> All capacitor made are not equal - it's a fact of manufacturing.

> About

> : >> half

> : >> the capacitors will work better than they were designed to, and the

> other

> : >> half will not work as well.

> : >

> : > Not quite correct. Almost all work at least as good as they were

> : > designed for. Some will work far better. Cofidence levels - all

> : > capacitors must at least meet specs - what they are intended to do.

> : >

> :

> : You really don't know anything do you?

> :

> : Capacitors are produced is such large quantities that the conformance to

> : specification is done by testing a sample of each batch only. It is a

> : fundamental requirement of sample testing that you have to accept that

> items

> : that do not conform to specification will be accepted. If you cannot

> accept

> : that then you can't do sample testing. Also, if you have a look at any

> : sample testing tables,

>

> Bwahahahahahah!

> You really don't know anything about Quality Control, do you?

>

 

Probably more than you do sunshine.

> Do these words mean anything to you: Mean, Variance, Standard Deviation?

>

 

Certainly do. Thats how sampling tables get produced in the first place.