Typical ESR values

[Dishum]

I'm a hobbyist who doesn't have an ESR meter or (usually) a
choice of specific capacitor models and I'd like to have some
idea of the kind of ESR values one would expect from capacitors
that are neither particularly good nor particularly crappy in
that respect. I'll really appreciate it if you could cite some
ballpark figures for -

1. 1uF/50V wet Al electrolytic
2. 100uF/25V wet Al electrolytic
3. 1000uF/50V wet Al electrolytic
4. 1uF/25V tantalum

 

[Phil Allison]

"Dishum"

I'm a hobbyist who doesn't have an ESR meter or (usually) a choice of
specific capacitor models and I'd like to have some idea of the kind of
ESR values one would expect from capacitors that are neither particularly
good nor particularly crappy in that respect. I'll really appreciate it if
you could cite some ballpark figures for -

1. 1uF/50V wet Al electrolytic
2. 100uF/25V wet Al electrolytic
3. 1000uF/50V wet Al electrolytic
4. 1uF/25V tantalum

** Measured from my parts bins:

1 = 3.1 ohms
2 = 0.5 ohms
3 = 0.06 ohms
4 = 4.2 ohms

In each case, the figure is for high frequency ESR or impedance at 100kHz.

ESR rises at low frequencies ( under 500Hz ) and falls with increasing
temperature.

Also, when an electro goes bad (ie dries out ) - ESR rises first followed
much later by a reduction in actual uF.



.... Phil

 

[Dishum]

"Dishum"


** Measured from my parts bins:

1 = 3.1 ohms
2 = 0.5 ohms
3 = 0.06 ohms
4 = 4.2 ohms

In each case, the figure is for high frequency ESR or impedance
at 100kHz.

ESR rises at low frequencies ( under 500Hz ) and falls with
increasing temperature.

Also, when an electro goes bad (ie dries out ) - ESR rises
first followed much later by a reduction in actual uF.

Thanks a lot.

 

[Phil Allison]

"Dishum"

"Phil Allison"
Thanks a lot.

** Thank you for a refreshingly clear question.




..... Phil

 

[Phil Allison]

"John Larkin"
"Phil Allison"

"Dishum"

That seems high for the tantalum. I seem to recall numbers like a
couple tenths of an ohm.

See page 5:

http://www.farnell.com/datasheets/33794.pdf

For a 1uF example at 25V or 35V, ESR values of 8 to10 ohms are quoted.



.... Phil

 

[Joerg]

I tried a standard leaded gumdrop tantalum, 1 uF at 35 volts, and got
about 0.75 ohms.

22u 16v was about 0.35 ohms.

Tantalum ESR tends to be in sort of a sweet spot for taming voltage
regulators, both switchers and linear.

Until they have exploded, that is

 

[Tim Williams]

ftp://jjlarkin.lmi.net/Tant_ESR_Rig.JPG

ftp://jjlarkin.lmi.net/Tant_ESR_Scope.JPG

Yes, suffice it to say, even though (dry slug) tantalums tend to have ESR
comparable to (higher grade) electrolytics, they are far, far simpler:
while lytics suffer from complicated ESL effects, tantalums are
essentially the inductance of the body length and that's it. The
equivalent circuit of C, ESR and ESL is very representative, and this
makes ripple voltage much more manageble.

And of course, polymers are just about ideal, yadda yadda.

Tim

 

[Phil Allison]

"Tim Williams is so full of shit "

Yes, suffice it to say, even though (dry slug) tantalums tend to have ESR
comparable to (higher grade) electrolytics, they are far, far simpler:

** Their failure modes are many and failures far more common too.

while lytics suffer from complicated ESL effects,

** Horse poo.

tantalums are essentially the inductance of the body length and that's it.

** Same goes for most electros too.


.... Phil

 

[Phil Allison]

"John Larkin"
"Phil Allison"

If you keep dV/dT down, they are very reliable.

** Absolute crap.

As fucking usual, Larkin has no idea of what he speaks and does not give a
shit either.

FOAD - septic pisshead.



.... Phil

 

[Phil Allison]

"John Larkin"

"Phil Allison"


I've used well over 100,000 tantalum caps in the last 6 years or so.
53,000 of 2.2u 20v alone. The only ones that failed were loaded
backwards or were on power rails that had high dV/dT available.

** So you have NOT seen the general failure rates with all brands of tants
and across all types of equipment.

You know no-one who has and do not give a shit either.

**** off to hell - you rabid, septic psychopath.

 

[Phil Allison]

"John Larkin"

"Phil Allison"


I see very low failure rates in the equipmennt I design. I'm sure
there is badly designed gear that blows tantalum caps.

I'm not a repair tech, so I don't deal with a lot of equipment
designed by somebody else.

** SO SHUT THE **** UP

- YOU BLOODY IMBECILE !!!!!!!




.... Phil

 

[JW]

"John Larkin"
"Phil Allison"


See page 5:

http://www.farnell.com/datasheets/33794.pdf

For a 1uF example at 25V or 35V, ESR values of 8 to10 ohms are quoted.

I thought the same thing that JL did, so taking a look at Digikey:
http://search.digikey.com/scripts/D...y=0&lang=en&site=us&KeyWords=1uf+25v+tantalum
7.5 to 8 ohms.

 

[JW]

I thought the same thing that JL did, so taking a look at Digikey:
http://search.digikey.com/scripts/D...y=0&lang=en&site=us&KeyWords=1uf+25v+tantalum
7.5 to 8 ohms.

Sorting by ESR there's some as high as 20 ohms!

 

[Martin Brown]

That sounds very reasonable. But there seems to be another quicker form
of "goes bad" that happens with annoying regularity on PC motherboards -
usually to the low voltage ram PSU capacitors but sometimes elsewhere.

I have just had an annoying incident with my own main PC motherboard
where the ram PSU capacitors ATWB 1800uF 6.3v (nominally ultra low ESR)
had started to bulge and over the past month a rock solid machine turned
into something that required a several goes just to get past the POST.
The situation seemed to be worst from a cold start after a weekend off
and once warmed up the machine would become "reliable" after a fashion.

I thought all the bother with dodgy electrolytes outgassing had been
fixed a long time ago, but I seem to have a similar fault on a modern
board

I finally attacked the motherboard with a soldering iron today and was
quite disappointed to find that at the low power and frequency my basic
tester uses they measured as OK at 1820 and 1940uF and <0.05R. I presume
they only give up the ghost at ~100kHz and a couple of amps ripple. The
ends were obviously bulging and they had taken on a rakish angle on the
board as they expanded. I was a bit surprised that they still measured
OK but went ahead and put new Rubicon 1800uF 10v caps in their place.

It seems to have done the trick <FX> crosses fingers </FX>.

Regards,
Martin Brown

 

[Phil Allison]

"Martin Brown"

I finally attacked the motherboard with a soldering iron today and was
quite disappointed to find that at the low power and frequency my basic
tester uses they measured as OK at 1820 and 1940uF and <0.05R.

** Low ESR types of that value should be no more than 3 to 10 milliohms.

At 10 times over and bulging - they are comprehensively stuffed.



.... Phil

 

[Martin Brown]

"Martin Brown"



** Low ESR types of that value should be no more than 3 to 10 milliohms.

Thanks for this, but I can't measure series resistance down that low.
It's just a quick and dirty tester.

At 10 times over and bulging - they are comprehensively stuffed.

That is certainly true. It seems to behave with the new capacitors in.

The bulging was the give away. The ones that bulged all had brown
sleeves, an "X" on the end cap and were ATWB by maker Toshin Kogyo.

Datasheet tends to suggest that about 15mR is normal at 100kHz.
(reading between the lines at 1800uF which isn't listed here)
http://www.ost.com.tw/PDF/TK/EC_TK_ATWB.pdf

The Rubicon 10v ZLJ part from its datasheet was good for 2.5A ripple and
about 30mR @ 100kHz which is in the right ballpark.

Basically I couldn't measure the differences between them on the bench
with a simple quick tester (and at low current).

Regards,
Martin Brown

 

[John Devereux]

On Tue, 24 Jan 2012 20:21:25 -0800, John Larkin wrote:

[...]

ftp://jjlarkin.lmi.net/Tant_ESR_Rig.JPG

ftp://jjlarkin.lmi.net/Tant_ESR_Scope.JPG

John

"The image “ftp://jjlarkin.lmi.net/Tant_ESR_Rig.JPG†cannot be displayed
because it contains errors."

I thought you were getting a real web site? Can't you use flikr in the
mean time?

It's fine, never had a problem with any of Johns FTP images.

Must be you!

 

[John S]

"The image “ftp://jjlarkin.lmi.net/Tant_ESR_Rig.JPG†cannot be displayed
because it contains errors."

I thought you were getting a real web site? Can't you use flikr in the
mean time?

Tim -

Try: copy the link and paste into browser address bar.

 

[Fred Abse]

"The image ftp://jjlarkin.lmi.net/Tant_ESR_Rig.JPG cannot be displayed
because it contains errors."

Works fine for me, using wget and display.

 

[Jamie]

"The image “ftp://jjlarkin.lmi.net/Tant_ESR_Rig.JPG†cannot be displayed
because it contains errors."

I thought you were getting a real web site? Can't you use flikr in the
mean time?

works for me?

Jamie