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31st Aug 2009, 6:51 pm | #1 |
Retired Dormant Member
Join Date: Aug 2008
Location: Bellac, 87. France.
Posts: 357
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ESR Meter advice
I want to build one. Is this one recommended? http://ludens.cl/Electron/esr/esr.html
The only part I dont understand is the transformer. Is it possible to find a scavenged pc/amp one from the resistances? |
31st Aug 2009, 7:24 pm | #2 |
Rest in Peace
Join Date: Apr 2008
Location: Worcester, Worcestershire, UK.
Posts: 330
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Re: ESR Meter advice
I would say the answer to your question is no. However having looked at the details of the construction, as the designer says almost any ferrite core will do. The only critical thing is the number of turns which he has quoted. I have not tried it myself yet but intend to do so. If you are really stuck I could probably find you a suitable Vincor to wind it on
Pat G3IKR |
31st Aug 2009, 7:44 pm | #3 |
Heptode
Join Date: Jun 2004
Location: Ilkley, West Yorkshire, UK.
Posts: 656
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Re: ESR Meter advice
Hi Humphrey,
I've built this circuit and it works very well. I actually used a scavenged transformer from an old computer power supply and had no problems. In fact I tried a few and they all worked without any real difference in performance. Perhaps I was lucky, but in the end I simply used the one that was the best fit in terms of size! I also have two professionally built ESR meters and this one produces readings very much in line with the them. The additional circuit board on the back of the meter is just a simple 'power off' timer because I tend to leave battery powered test gear on and I'm always finding the battery flat when I want to use it! Regards Colin
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Colin Armstrong |
31st Aug 2009, 9:01 pm | #4 |
Heptode
Join Date: Mar 2009
Location: Portsmouth, Hampshire, UK.
Posts: 674
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Re: ESR Meter advice
There is an interesting point about this circuit, the mid scale reading is 5 ohm rather than the 10 ohm (=R6) that might be expected.
I believe that this is caused by the unity gain bandwidth of the TL062 being only 1MHz. This implies that gain before the diodes is about 20 at best (F = 50kHz) leading to a fair amount of non linearity and an expanded scale at the 'low ohms' end. The meter scale provided takes this into account. Jim |
31st Aug 2009, 10:04 pm | #5 |
Octode
Join Date: Nov 2005
Location: Ayrshire, UK.
Posts: 1,096
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Re: ESR Meter advice
I built the one from 'Television' magazine. Works fine.
BTW Don't you just hate and despise people like Colin who build and finish their projects to such a high standard. Hate him, hate him, hate him... TimR
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All those moments will be lost in time, like tears in rain. |
1st Sep 2009, 11:30 am | #6 |
Retired Dormant Member
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Location: Hifa Israel
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Re: ESR Meter advice
hi,i also recomend the "television" one-all the parts are standard.
as for this circuit-i think a driver xfmer from the horizantal o/p of a modern tv should do. (but i havent tried it) |
1st Sep 2009, 12:04 pm | #7 |
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Re: ESR Meter advice
Is the one from "Television" in the public domain now?
Could it be Posted? Alan |
1st Sep 2009, 6:27 pm | #8 |
Retired Dormant Member
Join Date: Aug 2008
Location: Bellac, 87. France.
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Re: ESR Meter advice
Is it possible to dispense with the 5 volt regulator and use a 4.5 torch battery instead? (i am fairly new to this) I have a scrap Packard Bell pc monitor with some likely looking transformers.
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1st Sep 2009, 7:14 pm | #9 | |
Heptode
Join Date: Mar 2008
Location: Forest of Dean, Gloucestershire, UK.
Posts: 648
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Re: ESR Meter advice
Quote:
I built one to the original article and, as others have said, it works very well. Hugh |
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1st Sep 2009, 8:34 pm | #10 | |
Rest in Peace
Join Date: Oct 2006
Location: North Wiltshire, UK.
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Re: ESR Meter advice
Quote:
Ian |
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2nd Sep 2009, 8:14 am | #11 | |
Retired Dormant Member
Join Date: Jul 2005
Location: West Yorkshire, UK.
Posts: 1,700
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Re: ESR Meter advice
Hi,
Quote:
The resistances aren't given. The numbers '400' and '20' on the diagram are the number of turns of wire on primary and secondary respectively. So it's easy enough to make. 400 turns is within the limits of my patience, anyway. Much more than that and I start thinking about coil winders... It appears that salvaged ferrite cores from old PSUs etc. are likely to work too. What you wind the transformer on doesn't seem too critical. I think I'll be building one myself fairly soon; I think I can do it without buying anything Cheers, Kat |
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2nd Sep 2009, 1:35 pm | #12 |
Hexode
Join Date: Sep 2008
Location: Charlton Mackrell, Somerset, UK.
Posts: 315
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Re: ESR Meter advice
If you want to avoid coil winding have a look at this: http://www.members.shaw.ca/swstuff/esrmeter.html I've been using this design for few years.
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12th Sep 2009, 11:39 am | #13 |
Retired Dormant Member
Join Date: Aug 2008
Location: Bellac, 87. France.
Posts: 357
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Re: ESR Meter advice
I made it on veroboard and a small transformer from an old PB monitor. The meter is from an old £4.99 multimeter and it worked fine first time. Now to make a case for it.
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