Author Topic: LCR vs DMM  (Read 14156 times)

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Offline requimTopic starter

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LCR vs DMM
« on: October 15, 2011, 09:23:05 am »
I just acquired a Fluke 87 V and I am looking at purchasing an LCR, but then I started looking at what the Fluke does and it already measures capacitance and resistance, so I'm asking myself, why buy an LCR when the Fluke already measures the two values I'm trying to get?  Other than the LCR measuring inductance, what are the advantages/reasons for buying an LCR?

 

Offline Psi

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Re: LCR vs DMM
« Reply #1 on: October 15, 2011, 10:00:21 am »
LCRs are normally
- More accurate
- Able to read a wider range of values
- Can read an inductor at several different frequencies.
- Some can read capacitor ESR
- Can show if the component is within a set tolerance 1%,5%,10% etc (useful for testing many components quickly)
- Have probes and leads which are better designed to measure values without interfering themselves

And i'm sure there are other things i've missed.

LCR's are definitely handy to have but they're not really a 'must have' unless you plan to do work that requires that sort of accuracy (or, in your case, the ability to read inductors).

I bought a Peak brand LCR, they're pretty basic feature-wise but are relatively cheap and very portable.
I got the kit in a case including the peak DCA (a component tester). Which gives you all sorts of useful info from pretty much any semiconductor you connect to it,  pins,forward voltage etc). The whole kit is ~100GPB+shipping from www.peakelec.co.uk
« Last Edit: October 15, 2011, 10:01:52 am by Psi »
Greek letter 'Psi' (not Pounds per Square Inch)
 

Offline sub

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Re: LCR vs DMM
« Reply #2 on: October 15, 2011, 10:02:41 am »
They may also self-calibrate to remove the effect of the test leads on the measurements, pretty important if you're measuring in the picofarads.

Have a look at http://cp.literature.agilent.com/litweb/pdf/5990-7778EN.pdf for an example of some of the possible functionality (albeit from a reasonably high-end handheld meter).
 

Offline Conrad Hoffman

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Re: LCR vs DMM
« Reply #3 on: October 15, 2011, 11:49:06 pm »
IMO, the only LCR meter worth having will give you the dissipation factor of capacitors and the Q of inductors. Just knowing a capacitance value (DMM or cheap C-meter) isn't sufficient to tell you if the part is any good or not. Just knowing the ESR is actually better but still inadequate to get the full picture. You need both numbers!
 

Offline EEVblog

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Re: LCR vs DMM
« Reply #4 on: October 16, 2011, 12:06:25 am »
IMO, the only LCR meter worth having will give you the dissipation factor of capacitors and the Q of inductors. Just knowing a capacitance value (DMM or cheap C-meter) isn't sufficient to tell you if the part is any good or not. Just knowing the ESR is actually better but still inadequate to get the full picture. You need both numbers!

I agree. If you are getting an LCR meter, make sure it has that stuff.

Dave.
 

Offline kripton2035

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Re: LCR vs DMM
« Reply #5 on: October 16, 2011, 08:39:40 am »
if you want you can build yourself a lcr meter with all these measured values : c, esr, d, q
here on my web site some free schematics
regards,

http://kripton2035.free.fr/lcr-repository.html
 

Offline MajorEE

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Re: LCR vs DMM
« Reply #6 on: October 17, 2011, 07:35:22 pm »
IMO, the only LCR meter worth having will give you the dissipation factor of capacitors and the Q of inductors. Just knowing a capacitance value (DMM or cheap C-meter) isn't sufficient to tell you if the part is any good or not. Just knowing the ESR is actually better but still inadequate to get the full picture. You need both numbers!

I agree. If you are getting an LCR meter, make sure it has that stuff.

Dave.


Hey Dave, Can you do a review on the Agilent LCR Meter vs others. I am contemplating buying the new one that came out (Not sure if you got one of those to review) but I do know you had several LCR meters sent to you and I haven't seen a review on the others/shootout.

It would be really helpful as I'm starting to do a lot of work with inductors and RF.

Thanks!!

Respectfully,
MajorEE
 

Offline EEVblog

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Re: LCR vs DMM
« Reply #7 on: October 17, 2011, 09:55:18 pm »
The EIT labs LCR meter is on the UPS truck.
The new Agilent one I have asked for and am waiting for a response.

Dave.
 

Offline grenert

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Re: LCR vs DMM
« Reply #8 on: October 18, 2011, 01:15:01 am »
The IET Labs meter is made for them by DER EE, in Taiwan.  I contacted DER EE about the meter, and they referred me to IET.  Here is their product link:
http://www.deree.com.tw/LCR-meter.htm
 

Offline Ronnie

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Re: LCR vs DMM
« Reply #9 on: October 18, 2011, 08:12:40 am »
My concern on IET Labs DE-5000 is mentioned by robrenz from another post
"The main chip has an epoxy smear to cover the identification" https://www.eevblog.com/forum/index.php?topic=4909.msg65652#msg65652
It is possible the epoxy may cause reliability issue in the future   ???
 


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