What is ESR?
Sofie
ESR = Effective Series Resistance.
Especially important when electrolytics are used in higher frequency
applications such as SMPS and television deflection circuits.
An electrolytic can test good on most other testers and even measure the
correct value but if the ESR is high, it will not perform properly in many
circuits, especially when higher frequencies are encountered.
About 12 or 13 years ago.....until the proliferation of SMPS and other
circuitry that utilizes a lot of electrolytics in other that simple "bypass"
or "filtering" applications, most servicers never heard of ESR or even had a
means to test for it. At the present time, the ESR meter is probably the
most used piece of test equipment on most service benches............also it
can be a real time saver when chasing down problems.
Best Regards,
Dan Sofie
Electronics Supply & Repair
==============================================
Russel Osborne <russelj...@uswest.net> wrote in message
news:39c42675...@news.uswest.net...
> I don't work on tv's or vcr's.The caps we use are almost all very
> small(nano range or smaller) surface mount chip caps that we just
> replace if they are suspect.
> So, could someone please explain ESR or point out a website that does
> to me? I don't even know what ESR stands for :-)
> tia,
> russ
Russel Osborne
Noel Page
http://www.flippers.com/esrktmtr.html
Just follow the links.
Mind you I do not think an ESR meter will work for small caps.
Like the ones you describe. IT IS used on equipment as Dan Sofie
described.
craig osborn
JEFF
Stephen M. Powell
There is information at <http://octopus.freeyellow.com/esr.html> plus
links to other sites on the subject.
Reading my other page "99 Cent ESR Test Adapter"
<http://octopus.freeyellow.com/99.html> might give you some
understanding of why it more difficult to measure the ESR of
small capacitors.
ldis...@sun.science.wayne.edu
subject to abuse, the electrolyte tends to dry out. As it does the
capacitor takes a longer to charge. This looks [externally] like a
resistor is in series with the capacitor increasing the RC time
constant.
In article <39c42675...@news.uswest.net>,
Sent via Deja.com http://www.deja.com/
Before you buy.
bob parker
Hi,
Doug Jones has an excellent description of this subject available
as a .pdf file for download at [http://www.awiz.com/pdfs/tnote2.pdf].
Also see information on his highly-regarded Cap Wizard ESR meter, at
[http://www.awiz.com/cwinfo.htm]. :-)
Regards,
Bob
Bob Parker- electronics technician, Sydney Australia
home page: http://www.ozemail.com.au/~bobpar
PaulH96636
Jumping into the midst of this thread, sorry if it's been covered before, but
is this ESR factor similar to what was called 'power factor' many years ago?
-ph
Asimov
Re: What is ESR? (19 Sep 00 01:06:52)
>Also some call it equivelent series resistance.
Pa> Jumping into the midst of this thread, sorry if it's been covered
Pa> before, but is this ESR factor similar to what was called 'power
Pa> factor' many years ago? -ph
ESR and PF are related in the sense that they have the same causes but
they actually represent two different quantities. Since PF is a relative
figure of merit, it doesn't actually tell anything about the effective
losses. On the other hand ESR is a direct measurement of those losses.
The correct acronym is: _Effective _Series _Resistance.
... Thomas Edison invented the "Light Emitting Resistor"
bvo...@my-deja.com
and Heatkit R-C bridges have PF knobs but since I never got
manual with them it has been a mystery to me.
Bill
In article <MSGID_17=3a514=2f810.0_...@fidonet.org>,
"Asimov" <Asimov-RE...@bbs.juxtaposition.dynip.com>
wrote:
John Robertson
you a copy for $20US plus postage...it covers the Power Factor as well
as other setups.
John :-#)#
On Tue, 19 Sep 2000 22:11:19 GMT, bvo...@my-deja.com wrote:
>Please expand on the Power Factor explaination. Both my EICO
>and Heatkit R-C bridges have PF knobs but since I never got
>manual with them it has been a mystery to me.
>
>Bill
>
>In article <MSGID_17=3a514=2f810.0_...@fidonet.org>,
> "Asimov" <Asimov-RE...@bbs.juxtaposition.dynip.com>
>wrote:
>Sent via Deja.com http://www.deja.com/
>Before you buy.
(Please post followups or tech enquires to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
mailto:j...@flippers.com, web page http://www.flippers.com
"Old pinballers never die, they just flip out."
Sofie
Power Factor is still an up to date rating for capacitors (PF losses plus
ESR losses equal Dissipation Factor). While ESR is effectively a resistor
in series with a capacitor, PF is effectively a resistor in parallel with a
capacitor. This is a direct result of leakage resistance and the resultant
current that produces heat. More heat, more loss............more loss, more
heat.......etc, etc. A PF of 1 equals 100% leakage, 100% loss and no
capacitance. Most electrolytics are quite usable with a PF of under 0.2
In critical circuits with new high temp electrolytics a PF of 0.1 or
thereabouts...(or less).... is desirable.
(Especially in the older tube equipment with high voltage electrolytics) a
PF of greater than 0.2 can produce a lot of heat and thus cause a runaway
destruction of the capacitor.
Best Regards,
Dan Sofie
Electronics Supply & Repair
==============================================
<bvo...@my-deja.com> wrote in message news:8q8o9n$m0d$1...@nnrp1.deja.com...
> Please expand on the Power Factor explaination. Both my EICO
> and Heatkit R-C bridges have PF knobs but since I never got
> manual with them it has been a mystery to me.
>
> Bill
>
> In article <MSGID_17=3a514=2f810.0_...@fidonet.org>,
> "Asimov" <Asimov-RE...@bbs.juxtaposition.dynip.com>
> wrote:
Michael Caplan
<bvo...@my-deja.com> wrote in message news:8q8o9n$m0d$1...@nnrp1.deja.com...
> Please expand on the Power Factor explaination. Both my EICO
> and Heatkit R-C bridges have PF knobs but since I never got
> manual with them it has been a mystery to me.
The question of the relationship between ESR and Power Factor pops up here
every so often. It's too bad that Dejanews no longer goes back very far
because there have already been some thorough discussions.
In August 1997, there was a similar thread and I posted my take on the
distinction between ESR and "Dissipation Factor". It's a more theoretical
response than those that have appeared recently, but I'm reproducing it here
essentially as originally posted in the hope it contibutes to answering the
current question. (Dissipation Factor and Power Factor are essentially the
same for this discussion.)
----------------------
ESR is indeed related to Dissipation Factor (DF), but it is not the same. A
DF measuring device might not as readily identify a bad capacitor as does
the ESR meter. "Might not", because the reading varies and is not direct,
as described below.
Capacitors may be thought of as having pure capacitance (C) and some pure
resistance (R), the two being in series (there could also be a parallel
component). A ideal capacitor would have only C and no series R (and
infinite parallel R). However, there are the leads and plates that have
some resistance and constitute real R. Any R in series with C will reduce
the capacitor's ability to pass current in response to a varying applied
voltage, as in filtering or DC isolation applications, and it will dissipate
heat which is wasteful and could lead to failure of the component. As with
ESR, a lower DF (or higher Q, its inverse) may be equated with better
performance, all other things being equal.
(Now I get a bit more mathematical, but only using basic electronic theory
and formulas, so I hope most will be able to follow this.)
DF is defined as Rc/Xc, the ratio of the R in the capacitor (Rc) to the
reactance of the capacitor (Xc). The higher the Rc, the higher the DF and
the "poorer" the capacitor. So far so good.
The reactance (Xc) is a function of frequency. Xc=1/(2*pi*f*c). So for any
given capacitor, as the frequency goes up, Xc goes down. Now look back at
the formula for DF. DF is an inverse function of Xc. As Xc goes down, and
DF goes up, and vica-versa. So DF varies proportionally with frequency.
Here's an example using the common 22uFd, 16 Volt electrolytic that seems to
be at fault too often in many switched mode power supplies.
At 1000 Hz, this capacitor has an Xc of 7.2 Ohms. If the series Rc is only
0.05 Ohms, then the DF is 0.0069. That's good.
At 50,000 Hz, (more typical of SMPSs) this same capacitor would have an Xc
of only 0.14 Ohms. At this frequency the DF is 0.36, which is still fairly
low.
Now, change the Rc from 0.05 to 25 Ohms. At 1000 Hz, DF = 3.4. At 50,000
Hz, DF = 178.
So we see that DF is a function of frequency. The higher the frequency, the
higher the DF. DF is a measure of the capacitor "quality", but the figure
is meaningful only at the frequency of the test. (A good capacitor with an
ideal Rc of zero will have a DF of zero regardless of frequency.)
DF measuring devices (bridges, meters) can indeed be used to identify a bad
capacitor, but the user must interpret the level of measured DF that would
indicate a bad component, or have the DF specifications from the capacitor
manufacturer. Any manufacturer specifications for DF would be meaningful
only at the specified frequency so it would be necessary to ensure that the
testing frequency is the same. As an alternative, the user can calculate
the Rc by first measuring both DF and C, and then, knowing the test
frequency, determine if the measured Rc is excessive relative to Rc
calculated from the specified DF. (Rc=DF*Xc)
--------------
The current crop of ESR meters provide Rc readings directly (i.e.
independent of frequency) without any need for further calculation. They use
different measuring techniques, but as far as I understand, all are less
effective with smaller value capacitors. (The reason is that with smaller
capacitors (less than 1 uFd), the charge-discharge cycle on which the
measurement is based is too fast to get a reliable reading.) However, this
doesn't matter. The problem of high ESR is generally limited to
electrolytics which are typically used for higher values of capacitance.
With electrolytics, as has been mentioned elsewhere, the fault lies in the
gel electrolyte which tends to dry out. Smaller ceramic, mica, and
polystyrene capacitors are made of more stable components, and faults with
these are more likely to be "open", "shorted", or leaky, all of which will
be detectable by capacitance or resistance measuring devices.
In addition, the ESR meters are generally designed to provide reliable
readings without having to remove the component from the circuit. This is
not the case with the older R-C bridges.
Michael Caplan CET
anal...@my-deja.com
bvo...@my-deja.com wrote:
> Please expand on the Power Factor explaination. Both my EICO
> and Heatkit R-C bridges have PF knobs but since I never got
> manual with them it has been a mystery to me.
>
>
>
Bill,
I have an Eico capacitor checker. If it's the same model you have, I
can get a copy of the manual to you somehow. If interested, let me
know. I'll have to check on the model number, don't know it off the top
of my head.
I've just receiently used the Eico to check an old capacitor and came
up with some of the same questions that have been posted here. I'll
have to read up on all these postings. Thanks to all who have
contributed.
analogman