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From: ehsjr on 21 Dec 2007 23:40
robb wrote:
> "Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_(a)charter.net> wrote
> in message news:IqZaj.75$dY1.43(a)newsfe02.lga...
>
>>robb wrote:
>>
>>
>>>"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_(a)charter.net>
>
> wrote
>
>>>in message news:9DXaj.6331$Tt5.455(a)newsfe07.lga...
>>>
>>>>robb wrote:
>>>>
>>>>>so i googled for some ESR meter plans and settled on this
>
> one
>
>>>>>http://ludens.cl/Electron/esr/esr.html
>>>>>
>>>>
>>>>My opinion, It does not come close to actually
>>>>giving you a true ESR reading.
>>>>
>
> [ trimmed ] ...
>
>>Jamie says .....
>> My self, I would of used a bridge type sensing circuit from
>
> the
>
>> source and from the cap test point with a low (R) between the
>
> source
>
>> and test cap to measure the offset on the transition period.
>> With this type of config, the cap would be in as a shunt and
>
> not as
>
>> a series component.
>> all one would need to do is cross the leads for 0
>
> calibration before
>
>>test begins.
>>
>
>
> Hi jamie speaking of using a bridge circuit how does this design
> look ?
>
> http://www.qsl.net/iz7ath/web/02_brew/15_lab/06_esr/
>
> If it is not obvious i am looking for cheap (free) ESR
> schematic/plans to build
> thanks for the help ,
> robb
>
>

I built that one, the cost is low, and it works fine
for what you want to do. If you want a laboratory
grade instrument, look elsewhere.

Ed
From: Jan Panteltje on 22 Dec 2007 07:07
On a sunny day (Fri, 21 Dec 2007 18:44:29 -0500) it happened "robb"
<some(a)where.on.net> wrote in <13mojqlqn7nq82a(a)corp.supernews.com>:

>
>"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_(a)charter.net> wrote
>in message news:9DXaj.6331$Tt5.455(a)newsfe07.lga...
>> robb wrote:
>>
>> > so i googled for some ESR meter plans and settled on this one
>> >
>> > http://ludens.cl/Electron/esr/esr.html
>> >
>> My opinion, It does not come close to actually giving you a
>true
>> ESR reading.
>> All the design is doing is relying on high valued capacitors
>assumed
>> to still have life and hoping to display the effective series
>resistance
>> in them by assuming the Xc to be at a very low value with the
>50khz
>> referenced used.
>> In practice, that isn't a real ESR meter.
>>
>
>so this luden's ESR gives no useful info about a cap ? and its
>a waste of time design ?
>
>Thanks for advice Jamie,
>robb

I have no ESR meter, but many times if I wanted to know about caps
I just used 2 scope channels, substract, and in that way monitor
the voltage over the cap, and IF it shows fast transients the cap
is defective.
This method works nice in switchmodes.
And indeed the applying a pulse method is likely the best, and can be used
in the same way.
I hope you have an analog scope :-)




From: Paul Mathews on 22 Dec 2007 11:19
On Dec 21, 5:37 pm, "robb" <s...(a)where.on.net> wrote:
> "Jamie" <jamie_ka1lpa_not_valid_after_ka1l...(a)charter.net> wrote
> in messagenews:IqZaj.75$dY1.43(a)newsfe02.lga...
>
>
>
>
>
> > robb wrote:
>
> > > "Jamie" <jamie_ka1lpa_not_valid_after_ka1l...(a)charter.net>
> wrote
> > > in messagenews:9DXaj.6331$Tt5.455(a)newsfe07.lga...
> > >>robb wrote:
> > >>>so i googled for some ESR meter plans and settled on this
> one
>
> > >>>http://ludens.cl/Electron/esr/esr.html
>
> > >> My opinion, It does not come close to actually
> > >> giving you a true ESR reading.
>
> [ trimmed ] ...
> > Jamie says .....
> >    My self, I would of used a bridge type sensing circuit from
> the
> >   source and from the cap test point with a low (R) between the
> source
> >    and test cap to measure the offset on the transition period.
> >    With this type of config, the cap would be in as a shunt and
> not as
> >    a series component.
> >    all one would need to do is cross the leads for 0
> calibration before
> > test begins.
>
> Hi jamie speaking of using a bridge circuit how does this design
> look ?
>
> http://www.qsl.net/iz7ath/web/02_brew/15_lab/06_esr/
>
> If it is not obvious i am looking for cheap (free)  ESR
> schematic/plans to build
> thanks for the help ,
> robb- Hide quoted text -
>
> - Show quoted text -

For quick go/nogo indication, those simple ESR meters are handy and
useful. If you happen to have access to some simple equipment, you can
measure ESR and Self Resonant Frequency as follows:
Connect a signal generator output to the capacitor under test. Connect
the trigger output of the generator to scope trigger input. Connect 1
scope channel across cap under test. If a current probe is available,
monitor cap current with it. Otherwise, connect a low value resistor
in series with the ground lead of the cap under test and use a 2nd
scope channel to monitor the voltage across this sense resistor. With
the signal generator set at a low frequency (where Xc is high compared
to the sig gen's output Z), increase sig gen output and scope chan
sensitivities for clean waveforms. Increase frequency and observe
decreasing voltage across cap and increasing current through cap,
along with changing phase relationship. Readjust scope controls as
necessary. Eventually, you will reach a frequency where voltage and
current are in phase, and further increases in frequency cause
decreases in current. The ratio of voltage to current at this
frequency is a good estimate of ESR, and the frequency is near the
SRF. This procedure can be time consuming, but, if you have already
have scope and sig gen, you'll learn a lot about each cap you test.
Paul Mathews
From: Jean-Yves on 23 Dec 2007 05:32
In article <fkiuma$og2$1(a)aioe.org>,
Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote:

> >> robb wrote:
> >>
> >> > so i googled for some ESR meter plans and settled on this one
> >> >
> >> > http://ludens.cl/Electron/esr/esr.html
> >> >
> >> My opinion, It does not come close to actually giving you a
> >true
> >> ESR reading.
> >> All the design is doing is relying on high valued capacitors
> >assumed
> >> to still have life and hoping to display the effective series
> >resistance
> >> in them by assuming the Xc to be at a very low value with the
> >50khz
> >> referenced used.
> >> In practice, that isn't a real ESR meter.
> >>
> >
> >so this luden's ESR gives no useful info about a cap ? and its
> >a waste of time design ?
> >
> >Thanks for advice Jamie,
> >robb

I bought recently this one :

http://www.m3electronix.com/lcr.html
(the french version but it works the same)

nice kit, and with the esr meter you have for the same price of most of
esr meters kits , a precise LCR meter !!!
this is a valuable instrument I really enjoy mine !

regards.

--
Jean-Yves.
From: Michael A. Terrell on 23 Dec 2007 18:02
Jean-Yves wrote:
>
> In article <fkiuma$og2$1(a)aioe.org>,
> Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote:
>
> > >> robb wrote:
> > >>
> > >> > so i googled for some ESR meter plans and settled on this one
> > >> >
> > >> > http://ludens.cl/Electron/esr/esr.html
> > >> >
> > >> My opinion, It does not come close to actually giving you a
> > >true
> > >> ESR reading.
> > >> All the design is doing is relying on high valued capacitors
> > >assumed
> > >> to still have life and hoping to display the effective series
> > >resistance
> > >> in them by assuming the Xc to be at a very low value with the
> > >50khz
> > >> referenced used.
> > >> In practice, that isn't a real ESR meter.
> > >>
> > >
> > >so this luden's ESR gives no useful info about a cap ? and its
> > >a waste of time design ?
> > >
> > >Thanks for advice Jamie,
> > >robb
>
> I bought recently this one :
>
> http://www.m3electronix.com/lcr.html
> (the french version but it works the same)
>
> nice kit, and with the esr meter you have for the same price of most of
> esr meters kits , a precise LCR meter !!!
> this is a valuable instrument I really enjoy mine !


It only has a 12.5 KHz maximum test frequecy.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
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