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LCR Meter

 
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speakerguru
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Joined: 18 Nov 2005
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Location: Green Hut, Tovil

PostPosted: Tue Jan 10, 2012 10:54 am    Post subject: LCR Meter Reply with quote

I have finally taken my own advice and bought an LCR meter from the well known auction site. It was new, just under £14 (battery inc.), arrived after a few days and seems to work fine for my purposes. I'm amazed at the value for money. I am using it to measure guitar pickups but it looks like just the thing for anyone repairing crossovers (200μF max).
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audiolabtower
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PostPosted: Tue Jan 10, 2012 12:25 pm    Post subject: Reply with quote

Things have moved on since I did my 105 crossovers 25 years ago with a Wayne Kerr (Hee Hee!) professional bridge at work which literally was the size of a large suitcase!
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ColinR
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Joined: 31 Jul 2004
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Location: Staffordshire

PostPosted: Tue Jan 10, 2012 12:47 pm    Post subject: Reply with quote

Quote:
and bought an LCR meter from the well known auction site


Good toys aren't they Very Happy , you just have to find one "standard" component or an Aglient (Hewlett Packard) bridge once to determine the absolute error, then providing you replace the battery regularly you're set for life.

The circuit contributions made to this site were made on a reps ex-demo Meterman LCR-55 (£40) and an a £19.99 Meterman 33XR Capacitance Meter after the brand was eaten by Fluke(?).
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Thierry
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Joined: 02 Sep 2010
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Location: France - Outskirts of Paris

PostPosted: Thu Jan 12, 2012 7:27 am    Post subject: Reply with quote

Hello,
For those who want to measure ESR there's also a ready to assemble kit.

It's what I am using now and I am very happy with the performance, since it's on my table I saved a lot of time when repairing or restoring old electronics. And it is a mandatoy tool when it's about capacitors replacement in a crossover. That device measures L, C F and ESR of course and it is quite accurate.

Here's the description I wrote when I finished assembling the kit : http://translate.google.fr/translate?sl=auto&tl=en&js=n&prev=_t&hl=fr&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fdcx2496.fr%2FESR.php&act=url (Google translation, some parts are weird)

Slideshow of assembly and some measurements I did : https://picasaweb.google.com/109296933751482509949/ESRmetre?authkey=Gv1sRgCMvc8bKAyYOCbg#slideshow/5650757313281585090
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iso
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Joined: 29 Aug 2011
Posts: 215
Location: Finland

PostPosted: Thu Jun 21, 2012 9:04 pm    Post subject: LCR Meter Reply with quote

I have checked now capacitance figures of P60 crossover with 3 different LCR Meters. Measured figures of old crossover seems always be 5% too high. Situation was similar when I measured old Cantata crossover. Figures were also 5% too high when I bought new 2% caps from Falcon.

I have used Wavetek and two different Lutron LCR Meters. Measured figures have been very close to each other when measuring with these meters.

Does LCR Meter measuring system have any shortcomings compared to bridge measuring setup. It came to my mind if leakage current will make this difference?

Best Regards

Kimmo
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speakerguru
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Joined: 18 Nov 2005
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Location: Green Hut, Tovil

PostPosted: Fri Jun 22, 2012 7:33 am    Post subject: Re: LCR Meter Reply with quote

iso wrote:
Measured figures of old crossover seems always be 5% too high.

see http://www.hifiloudspeakers.info/Anatomy/KEFDocuments/KEFTopics/KEFTOPICS_Vol_3_No_3.pdf for a brief explanation of the KEF used to grade components into 1% bands and use high value capacitors with low value inductors to minimise response variations in production.
....or are you trying to say that somehow all components increase in value with age? I'm struggling to think of any mechanism whereby inductance can increase with age. Maybe the windings settle infinitesimally closer to the core Shocked .
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proffski
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Joined: 22 Aug 2003
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Location: Tewkesbury UK

PostPosted: Fri Jun 22, 2012 7:45 am    Post subject: Re: LCR Meter Reply with quote

I have my LCR meter calibrated every year... Wink
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iso
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Joined: 29 Aug 2011
Posts: 215
Location: Finland

PostPosted: Fri Jun 22, 2012 11:40 am    Post subject: Leakage current Reply with quote

I was trying to find out if leakage current will alter mesured capacitance figures when using typical LCR Meter and if leakage current affects less to bridge mesuring. It seems obvious that capacitor with higher lekage current will hold the charge shorter time, than equal capacitor with less leakage current.

I do not think that inductors will change unless some kind of accidents have happened... broken cores etc.

Best Regards

Kimmo
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