Typical ESR values

[Jamie]

Nice trick. I slapped in a 10uF 35 V tant.

~80mV or 80mV/10 *50 =0.4 ohms.
http://imageshack.us/photo/my-images/545/tek0017.png/

lotsa ringing at the step...
What’s that about? Bad technique on my part?

http://imageshack.us/photo/my-images/40/tek0018.png/

George H.

Put a 50 ohm R across your gen output..


Jamie

 

[Jamie]

That ringing is about 40 MHz. The edge from my function generator
probably isn't fast enough to excite something like that. Still, it's
probably lead lengths or something causing all that ringing.

John

I find that some gen outputs have reactive circuits in them. Not
properly terminated to bring the Q down to 1 or less.

Also, I've seen problems with lack of shoot through on complemary
emitter followers as unity buffers on equipment exhibiting this effect.

A non reactive fixed load on the output normally fixes this. Ringing
can be suppressed if the device that is delivering the signal
has a high gain loop back and enough current handling to counter the
reaction.

Many signal generators do not have feed back on their final stage to
help the driving circuit maintain the output.

I've designed amplifiers to drive magnetic scan and focus coils and
one of the items in the design is to have the amplifier attempt to
counter act any reactive response, other wise, it'll show in the sweeps
and focusing.

That's my take on it

Jamie

 

[John S]

works for me?

Jamie

The question mark indicates you don't know whether it does or not. Are
you asking a question Dip Shit?

 

[Jamie]

Does this work?

http://dl.dropbox.com/u/53724080/Circuits/Tant_ESR_Rig.JPG

http://dl.dropbox.com/u/53724080/Circuits/Tant_ESR_Scope.JPG

The web site needs work, and it's kind of a nuisance to throw files up
onto. The FTP is really fast and easy, but some people can't see it.

John

Do you have a lot of smokers in your work area? why is that scope so
yellow? Or is that the natural color? my Rigol is near white.

btw, I have the 100mhz version, not the software hacked 50mhz, if
that makes any difference?

Jamie

 

[Jamie]

No. I'd never hire anybody who smokes.


why is that scope so



The Rigol is a little off-white, a faint cream color. Probably the
camera is set for daylight mode or something. But you're supposed to
be admiring the fabulous waveform, not the photography.

Yeah, forgot, the wave form looks nice
Jamie

 

[Martin Brown]

Does this work?

http://dl.dropbox.com/u/53724080/Circuits/Tant_ESR_Rig.JPG

http://dl.dropbox.com/u/53724080/Circuits/Tant_ESR_Scope.JPG

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

The web site needs work, and it's kind of a nuisance to throw files up
onto. The FTP is really fast and easy, but some people can't see it.

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

 

[Fred Abse]

Does this work?

http://dl.dropbox.com/u/53724080/Circuits/Tant_ESR_Rig.JPG

http://dl.dropbox.com/u/53724080/Circuits/Tant_ESR_Scope.JPG
Yes.


The web site needs work, and it's kind of a nuisance to throw files up
onto. The FTP is really fast and easy, but some people can't see it.

I still vote for ftp.

 

[Jasen Betts]

I don't exactly understand the situation. Got a sketch?

Does this involve tantalum caps?

A description should suffice [rum disclaimer inserted here]:

Yes -- I have eight output transformers in parallel from the same
current-limited PWM driver. Now, under normal conditions, all eight
channels are working correctly, so the current shares evenly, and all
the caps are happy (the maximum supply is 5A, so they each see a
maximum of 5A / 8 = 0.6A peak, so the RMS ripple is under 0.42A, fine
for a chip tantalum, though I have ceramic specified at the moment).
But under fault, the whole 5A could flow into just one channel, which
makes things "interesting". I may implement a "max-of-channels"
current limit for this.

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.

 

[josephkk]

Use your SoundCard and a little fussing and you can get down to
milliohms between the ranges of 1000Hz to 90kHz. Actually, 89kHz, but
can't get to 100kHz.

A little software and your Soundcard 24bit? running at 192kS/s dual
channel

I don't suppose that you have the source code for that do you? If so i
would like to have a copy.

?-)

 

[josephkk]

My code has the WORST users interface ever made! Source Code contains
too many proprietary processes and algorithms from another project and
is approx 2MB and relies on four libraries to be installed.

Try a search first, there are many prepackaged programs that you can
use.

If you still want your own, get software that exercises your soundcard
and start modifying that.

I'm open to discussion once you're set up.

No further comment is needed. You cannot provide, that is OK though.
Just asked in case you had something appropriately available.

?-)

 

[[email protected]]

On Jan 25, 9:55 pm, John Larkin
I don't exactly understand the situation. Got a sketch?

Does this involve tantalum caps?

A description should suffice [rum disclaimer inserted here]:

Yes -- I have eight output transformers in parallel from the same
current-limited PWM driver.  Now, under normal conditions, all eight
channels are working correctly, so the current shares evenly, and all
the caps are happy (the maximum supply is 5A, so they each see a
maximum of 5A / 8 = 0.6A peak, so the RMS ripple is under 0.42A, fine
for a chip tantalum, though I have ceramic specified at the moment).
But under fault, the whole 5A could flow into just one channel, which
makes things "interesting".  I may implement a "max-of-channels"
current limit for this.

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.

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

--

John Larkin, President       Highland Technology Incwww.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- Hide quoted text -

- Show quoted text -

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

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

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).

 

[JW]

]

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

*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'd like to see them put these in backwards:
http://www.vishay.com/docs/40044/299d.pdf

Even AlwaysWrong couldn't screw up with those.

 

[[email protected]]

]

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

*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'd like to see them put these in backwards:
http://www.vishay.com/docs/40044/299d.pdf

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

Even AlwaysWrong couldn't screw up with those.

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).

 

[JW]

]

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

*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'd like to see them put these in backwards:
http://www.vishay.com/docs/40044/299d.pdf

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

Even AlwaysWrong couldn't screw up with those.

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.

 

[[email protected]]

On Mon, 30 Jan 2012 19:18:41 -0800 (PST), George Herold

[...]

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

*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'd like to see them put these in backwards:
http://www.vishay.com/docs/40044/299d.pdf

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

Even AlwaysWrong couldn't screw up with those.

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.

That's why we also had the 4-pin caps (-++-). If they're off a hole there was
a direct short, which was easily found.