Re: don't buy
- From: "Jeff L" <levy_jeff@xxxxxxxxxxx>
- Date: Sun, 08 Apr 2007 19:14:37 GMT
"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@xxxxxxxxxxx> wrote in message
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Jeff L wrote:
"Damon Hill" <damon1SIX1@xxxxxxxxxxxxxx> wrote in messageIsn't that one of the reason's they are populer ? low ESR ?
news:Xns990BD2B2C57F8damon161attbicom@xxxxxxxxxxxxxxxxx
"colin" <colin.rowe1@xxxxxxxxxxxxxxxxxx> wrote in
news:iwRRh.2179$I%2.580@xxxxxxxxxxxxxxxxxxxx:
"John Larkin" <jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote in
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personnaly ive only had them explode when ive put them in backwards,
... not something I do very often,
although ive read quite a few people mention it here.
Experienced a couple that blew up after being put in frontwards.
(Cheap orange bead types; I suspect they were incorrectly marked.)
More likely internally shorted with a tantalum whisker, which caused an
internal fire.
They also fail from cumulative damage, especially from high di/dt, often
caused from putting them on fast rising supply rails.
--Damon
Yes, but exceed that nice little di/dt rating bad enough, and they go off
like a mini road flare. A common way to do this to use them as input caps,
and then hook up a low impedance power supply, eg a large battery or power
supply with large output caps etc, then a switch closure or a power
connector being plugged in and then kaboom!
Shorting them out would likely also exceed that rating.
MLCC caps are getting better and larger all the time with no major wear
mechanisms, and as John has mentioned, the "new" organic polymer caps work
good. With careful design considerations and the lower ESR, the ceramic caps
can end up cheaper and smaller with less total capacitance. Sometimes the
ESR is so low that you need to put a smallish resistor in series with the
cap to add some dampening, otherwise you can get LC resonance, especially
when a good ground *AND* power plane is not used.
--
"I'm never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5
.
- References:
- don't buy
- From: John Larkin
- Re: don't buy
- From: colin
- Re: don't buy
- From: Damon Hill
- Re: don't buy
- From: Jeff L
- Re: don't buy
- From: Jamie
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