Typical ESR values

Yes. These are much more user friendly to the outside world.

You should be able to throw files up onto your website by ftp if you want to and then publish their URL. Try creating a directory "temp" or even "ftp" on your website and treat it like you do with ftp:://

Then you can ftp stuff up and others can look at it how they like.

Regards, Martin Brown

Oooh, fancy. Looks like the Caribbean's answer to Makers Mark :)

Tim

It's actually from Guatemala.

Try some. Well worth the price.

John

Yes.

I still vote for ftp.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

--
For you, perhaps, but a true gourmand would acquiesce to that
some prefer the grape, and some the cane, without incurring judgment
and its attending rancor.

Whatever you say.

John

--
Thank you.

Under this fault condition in the fault current passing through the tantalum cap, or just visiting the neighbourhood?

energy density detonates tantalums, don't get them hot and charged at the same time.

--
?? 100% natural

What usually detonates them is high peak current, or equivalently high dV/dT.

--

John Larkin, President       Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

Mental picture: suppose you have a standard full-bridge forward converter, except it's supplied by constant current, allowing you to use caps directly after the rectifier, rather than an L+C filter (essentially, the L was moved to the primary side).

Now suppose one channel were accidentally shorted, then unshorted. Two things happen:

1. While shorted, all the supply current flows into the shorted channel. The other channels remain at roughly the same level, as they discharge relatively slowly under nominal load. Depending on just how short the circuit is, all the ripple will flow past the capacitor, so this isn't a problem, in and of itself.
2. When unshorted, supply current continues to flow into the formerly- shorted channel until it reaches the same voltage as the other channels, when current gets shared again. This charges the capacitor quite quickly.

I could easily add a shunt and PNP transistor to each side of each transformer primary as a rudimentary current limit, just dump it into the current feedback node. Kinda dirties up the circuit with all the extra hardware, but such is protection.

Tim

e

hnology.com=A0 jlarkin at highlandtechnology dot com

No, the worst thing about tant. caps is they get put in bakcwards*,

I spent an hour today, trying to figure out why the current limit kept turning on, at ~3 volts, but only under a good load???

George H.

*(at least one spelling mistake intentionally left in.) (with a failure time that varies between a minute and a day....) grumble

Incwww.highlandtechnology.com  jlarkin at highlandtechnology dot com

*MANY* moons ago, my boss was the Tantalum Cap Tzar for the corporation (how he got that "distinction", I haven't the foggiest). We were having all sorts of problems with fires caused by tants in backwards. Everything was tried, three pins (-+-), four pins (-++-), big lead/little lead, fuses, everything. No matter what, something like 1% of them got stuck in backwards (even to the point that when all else went right 1% were in the tubes backwards).

One day the manager of the local manufacturing/stuffing department called complaining that his "girls" were getting sore thumbs from sticking the capacitors into the boards. Yep, they were big/little lead caps and they were trying really hard to put the big lead in the little hole. They'd done a few thousand that way.

I had a bunch go off about 2" from my ear, while I was leaning over the bench try to figure out why the supply was limiting (I always brought systems up the first time with the supply in constant current mode).

Yeah, a lot of diodes have that same design defect.

John

--

John Larkin, President Highland Technology Inc

jlarkin at highlandtechnology dot com

Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators

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Yeah... a backwards cap finally 'dawned' on me and it took less than

30 seconds to lay my fingers on the problem. New run... they're all in backwards, except for a few I guess.

Does under voltaging (sp) make a few last longer? I swear I've had stuff powered up for few hours, and then get pictures sent of a 'brown' tantalum, in backwards. (Return costs are expensive, but ya gotta take care of your customers!)

George H.

George H.

[...]

I'd like to see them put these in backwards:

Even AlwaysWrong couldn't screw up with those. :)

Incwww.highlandtechnology.com jlarkin at highlandtechnology dot com

Conventional wisdom is that tantalums can run at -3 volts or -10% of rated voltage, whichever is more. Or less maybe.

Why put them in backwards?

**********************************

John Larkin, President Highland Technology, Inc

jlarkin at highlandtechnology dot com

Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation

That's sorta the "three pin" cap I was referring to above. These were "tombstone" variety, but the idea is the same.

Don't bet on it. Get them one position off, and what do you have? BTW, our boards had a hole every .100" (or .125", depending on the technology in use).

Oh. That would be a deal killer then. For those to work, you'd need a reasonable area around the cap with no vias.

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Well some can run at ~ -12V (-33%) for several hours before cooking themselves.

It was a mistake. Either we gave the board house the wrong polarity or they screwed up. There's this very tiny (+) sign on the tant. (through hole)

George H.

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