Electrolytic caps?

[Pooh Bear]

Here, I have a huge case of these, for starters:
http://dimensional.com/~melissa/photos/Cap1500uf100v.JPG

As they're designed for hand wiring as opposed to pcb mount, I doubt many
ppl would be interested in them these days.

You could always try shifting them on ebay though.


Graham

 

[Pooh Bear]

The way I do it, which I thought was standard, was to gradually raise the
voltage from zero over a period of minutes, monitoring for leakage all the
time, and then leave it charged to the rated voltage for some time.

I wouldn't call that the standard method but ramping the voltage sounds like a
nice idea. You still want to use a current limiting resistor though.

You also need to apply the rated voltage for some time IIRC to ensure that the
oxide film is fully reformed.

You can measure quite an increase in capacitance from doing this, even if
the capacitor didn't test out as defective to begin with.

As compared to the rated capacitance ?


Graham

 

[Pooh Bear]

It means that caps made during certain time periods and some
companies are prone to failure from dried out seals and depending on the
electrolyte used, the cpacitors may neeed to be re-formed.

I think the Japanese choice of calling electrolytics 'chemical caps' or
chemicons makes this more obvious. Probably the least reliable components
still in use but regrettably necessary.


Graham

 

[Pooh Bear]

I read in sci.electronics.design that Joerg <notthisjoergsch@removethisp


It took a long time to discover that sodium chloride (common salt)
contamination was responsible for short life of aluminium electrolytic
capacitors, simply because traces of salt are almost everywhere. So if
your old caps have, by chance or design, a low salt content, they may
well still be good.

Talking of salt messing things up....

Do you recall that GEC did a deal with Nat Semi IIRC to make a UK cmos fab
back in the 70s ?

One of the lecturers at UCL had been there and taught us semiconductor
physics. They could never get the process fixed. The chips would work - but
'go bad' after some months.

It was finally found that the the nichrome wire that they were using in the
ovens was quenched in a salt solution during the manufacturing process.
Sodium ions were 'boiling out' of the wire and entering the chips. Initially
this caused no problem until the sodium ions migrated into the active region
and threw the threshold voltages of the fets all over the place.

Sadly the problem was diagnosed too late and the project was dropped.


Graham

 

[keith]

I think the Japanese choice of calling electrolytics 'chemical caps' or
chemicons makes this more obvious. Probably the least reliable components
still in use but regrettably necessary.

Ok, why is "electrolytic" any worse of a term? Certainly we all know what
is bing talked about.

 

[Michael A. Terrell]

I think the Japanese choice of calling electrolytics 'chemical caps' or
chemicons makes this more obvious. Probably the least reliable components
still in use but regrettably necessary.

Graham

Yes, electrolytics are a cheap way to get a large capacitance and it
is a trade-off between size and cost against reliability. I have to
laugh at some of the people who condemn radio manufactures for using
cheap paper caps 75 years ago, yet they brag about tracking down the
cheapest chinese no name parts they can find for their restorations.
Not all plastic insulating films are of the same quality and I wonder
how long it will be before these new high voltage caps last before they
start breaking down. Will people be condemning them for their bad
choices in say, ten years?

On the other hand you can find NOS Sprague and other American made
electrolytic caps that are fifty years old with good seals and still
have the marked capacitance along with a good ESR. Not all of them, but
a lot higher percentage than current production electrolytic caps will
be at that age.

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

As they're designed for hand wiring as opposed to pcb mount, I doubt many
ppl would be interested in them these days.

You could always try shifting them on ebay though.

Audio repair guys can use those for the DC blocking cap on the output
stage of power amps.

 

[John Woodgate]

I read in sci.electronics.design that Pooh Bear <rabbitsfriendsandrelati

It was finally found that the the nichrome wire that they were using in
the ovens was quenched in a salt solution during the manufacturing
process. Sodium ions were 'boiling out' of the wire and entering the
chips. Initially this caused no problem until the sodium ions migrated
into the active region and threw the threshold voltages of the fets all
over the place.

One of the most spectacular of these trace effects is just touching a
THICK tungsten wire used for the filaments of big transmitting valves
with nickel-plated tweezers. Just try to bend the wire a bit and it
snaps like glass rod where it was touched.

 

[Melissa]

Audio repair guys can use those for the DC blocking cap on the output
stage of power amps.

So what are they worth to someone? $1 each?

--
Yours In Liberty, Melissa - Colorado, U.S.A.
http://melissasliberty.blogspot.com/

The last best hope for liberty, to give the world its first Bill of
Rights: http://www.UPAlliance.org/billofrights.htm

 

[John Fields]

So what are they worth to someone? $1 each?

 

[Pooh Bear]

Audio repair guys can use those for the DC blocking cap on the output
stage of power amps.

I doubt there's that many audio amps with ac coupled outputs still around
these days actually.


Graham

 

[Rich Grise]

As they're designed for hand wiring as opposed to pcb mount, I doubt many
ppl would be interested in them these days.

I don't recall if I've actually seen it, or just dreamt or fantasized it,
but it seems that one of those could be put on a PCB by poking slotted
holes.

Cheers!
Rich

 

[John Woodgate]

I read in sci.electronics.design that Rich Grise <[email protected]>

I don't recall if I've actually seen it, or just dreamt or fantasized
it, but it seems that one of those could be put on a PCB by poking
slotted holes.

Indeed: that's what we did for many years after the first printed boards
were introduced into the company's products (in 1957).

 

[Melissa]

I don't recall if I've actually seen it, or just dreamt or fantasized it,
but it seems that one of those could be put on a PCB by poking slotted
holes.

Oh yeah, they could be PC mounted.




--
Yours In Liberty, Melissa - Colorado, U.S.A.
http://melissasliberty.blogspot.com/

The last best hope for liberty, to give the world its first Bill of
Rights: http://www.UPAlliance.org/billofrights.htm

 

[Michael A. Terrell]

I don't recall if I've actually seen it, or just dreamt or fantasized it,
but it seems that one of those could be put on a PCB by poking slotted
holes.

Cheers!
Rich

Some consumer electronics used standard "FP" electrolytic caps on PC
boards my drilling larger holes and using a lot of solder. They tended
to get stress cracks so a modified version was made with smaller
terminals and part of the tabs cut away.

I leave it to you to figure out what "FP" means!

 

[Rich Grise]

Some consumer electronics used standard "FP" electrolytic caps on PC
boards my drilling larger holes and using a lot of solder. They tended
to get stress cracks so a modified version was made with smaller
terminals and part of the tabs cut away.

I leave it to you to figure out what "FP" means!

OK, I give up. There are a lot of surplus dealers selling "Mallory Type FP"
capacitors, but haven't found a definition yet. Is Mallory out of
business? One of the sellers said, "made to the original Mallory spec on
original Mallory equipment..."

But I'm at a loss as to "FP", unless it's something like "footprint" or
"four-prong". Flame-proof?

Any hints?

Thanks,
Rich

 

[Michael A. Terrell]

OK, I give up. There are a lot of surplus dealers selling "Mallory Type FP"
capacitors, but haven't found a definition yet. Is Mallory out of
business? One of the sellers said, "made to the original Mallory spec on
original Mallory equipment..."

But I'm at a loss as to "FP", unless it's something like "footprint" or
"four-prong". Flame-proof?

Any hints?

Thanks,
Rich

Its a "Fiber Plate". It was named after the insulated mounting plate
made to mount the can on a chassis without special tooling. I think it
used the same chassis punch as an octal tube socket so prototypes and
home brewers could mount it with little trouble. Most individually
boxed caps were shipped with the fiber plate as well as a metal plate to
use if the case was grounded. Small production runs would rivet the
metal plate in, but larger runs would have the four slots punched into
the chassis. The fiber plate was almost always riveted.

There was also a smaller three tab version with up to three sections.

Both types could also be mounted with a heavy clip that snapped
around the side of the can.

I may still have a couple new plates her to take pictures if you need
to see the shape.

 

[Rich Grise]

Its a "Fiber Plate". It was named after the insulated mounting plate
made to mount the can on a chassis without special tooling. I think it
used the same chassis punch as an octal tube socket so prototypes and
home brewers could mount it with little trouble. Most individually
boxed caps were shipped with the fiber plate as well as a metal plate to
use if the case was grounded. Small production runs would rivet the
metal plate in, but larger runs would have the four slots punched into
the chassis. The fiber plate was almost always riveted.

There was also a smaller three tab version with up to three sections.

Both types could also be mounted with a heavy clip that snapped
around the side of the can.

I may still have a couple new plates her to take pictures if you need
to see the shape.

I don't think that'll be necessary, but you can if you want to.

Thanks!
Rich

 

[Michael A. Terrell]

I don't think that'll be necessary, but you can if you want to.

Thanks!
Rich

I figured that you could visualize it, but I offered in case someone
had never seen the way they were used and couldn't wrap their mind
around it.

 

[Von Heler]

I don't recall if I've actually seen it, or just dreamt or fantasized it,
but it seems that one of those could be put on a PCB by poking slotted
holes.

Cheers!