"Scott W. Harvey" wrote in message
...

[snip]


I have tested brand new electrolytics and have found them to be as
much as 50% off rated capacity. Small coupling and bypass caps, though
are usually right on the money if they're good.

-Scott



That's interesting. I've checked some new electrolytics with my old
Heathkit cap checker, and they are almost always within 20% or so of the
indicated value. I'll check more later and see if it still holds true.

Frank Dresser

A tolerance of +100% -50% was more or less standard on old electrolytic
caps. Today, +50% -10% is customary, but some are still wider than that.

"Frank Dresser" wrote in message
...

"Scott W. Harvey" wrote in message
...

[snip]


I have tested brand new electrolytics and have found them to be as
much as 50% off rated capacity. Small coupling and bypass caps, though
are usually right on the money if they're good.

-Scott



That's interesting. I've checked some new electrolytics with my old
Heathkit cap checker, and they are almost always within 20% or so of the
indicated value. I'll check more later and see if it still holds true.

Frank Dresser

BFoelsch wrote:
A tolerance of +100% -50% was more or less standard on old electrolytic
caps. Today, +50% -10% is customary, but some are still wider than that.

You've got to look long and hard to find any with that loose a spec
anymore. I just paged thru the Mouser catalog and a quick glance sez
everything offered is +/-20% except for the old Vishay/Sprague TVA-Atoms
and Littl-Lytics.

-Bill

BFoelsch wrote:
A tolerance of +100% -50% was more or less standard on old electrolytic
caps. Today, +50% -10% is customary, but some are still wider than that.

You've got to look long and hard to find any with that loose a spec
anymore. I just paged thru the Mouser catalog and a quick glance sez
everything offered is +/-20% except for the old Vishay/Sprague TVA-Atoms
and Littl-Lytics.

-Bill

A tolerance of +100% -50% was more or less standard on old electrolytic
caps. Today, +50% -10% is customary, but some are still wider than that.

"Frank Dresser" wrote in message
...

"Scott W. Harvey" wrote in message
...

[snip]


I have tested brand new electrolytics and have found them to be as
much as 50% off rated capacity. Small coupling and bypass caps, though
are usually right on the money if they're good.

-Scott



That's interesting. I've checked some new electrolytics with my old
Heathkit cap checker, and they are almost always within 20% or so of the
indicated value. I'll check more later and see if it still holds true.

Frank Dresser

Frank Dresser wrote:
"Scott W. Harvey" wrote in message


I have tested brand new electrolytics and have found them to be as
much as 50% off rated capacity. Small coupling and bypass caps, though
are usually right on the money if they're good.

That's interesting. I've checked some new electrolytics with my old
Heathkit cap checker, and they are almost always within 20% or so of the
indicated value. I'll check more later and see if it still holds true.

Electrolytics are usually rated for -10%, +50% tolerances, and most of
them will measure higher than the package says. Check the data sheet
on the caps.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Frank Dresser wrote:
"Scott W. Harvey" wrote in message


I have tested brand new electrolytics and have found them to be as
much as 50% off rated capacity. Small coupling and bypass caps, though
are usually right on the money if they're good.

That's interesting. I've checked some new electrolytics with my old
Heathkit cap checker, and they are almost always within 20% or so of the
indicated value. I'll check more later and see if it still holds true.

Electrolytics are usually rated for -10%, +50% tolerances, and most of
them will measure higher than the package says. Check the data sheet
on the caps.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"Frank Dresser" wrote in message
...


Here's the results, checked on a Heathkit IT-28:

BC HP 68ufd 200V
68-62-60

BC HP 47ufd 200V
43-44-46-44-44-43-45-45

BC HP 33ufd 200V
33-30-29-31-31-30-33-32

Xicon 47ufd 160V(Marked +/- 20%)
44-43-43-46-43-44-48

Xicon 33ufd 160V(Marked +/- 20%)
32-34-34-34-34-32-33-32

Panasonic 47ufd 450V
45-46-43

Ducati 100ufd 25V (about 30 years old)
98-100-100-98-105-95-105-102-110-100-110

Planet Liticap 40ufd 450V (used pull, maybe 40 years old)
38

Frank Dresser

In article , "Frank
Dresser" writes:

Here's the results, checked on a Heathkit IT-28:

Interesting. With very few and small exceptions, every cap measured LESS than
marked. And we thought lytics were being made with very high positive
tolerances, up to 100% or double the value.

I guess you get (almost) what you pay for, no mas! --Mike K.

Oscar loves trash, but hates Spam! Delete him to reply to me.

"Mike Knudsen" wrote in message
...


Interesting. With very few and small exceptions, every cap measured LESS
than
marked. And we thought lytics were being made with very high positive
tolerances, up to 100% or double the value.

I guess you get (almost) what you pay for, no mas! --Mike K.


I can't be sure the checker isn't just reading low. I do get repeatable and
sensible readings from it.

I also don't know if the caps I checked just by chance happened to be
generally bunched around common values, or if they are actually made with
more precision than they are rated for. It's a small sample.

But modern (maybe even 50 years ago) manufacturing ought to be able to make
a reasonably precise product as long as they are able to stick with a
process that is known to work. I have to figure that the capacitor
manufacturers know what they are doing, they regularly check samples of
their product and can make running changes to hit their target specs with
almost every lot.

Just as speculation, let's say cap manufacturers have learned to make
electrolytic capacitors with good precision at little extra cost. And let's
imagine that setting the target capacitance to 5% - 10% low reduces the cost
of the "active ingredients" by 5% -10%. Well, that would be a nice reward
for knowing how to do the job!

Frank Dresser