Are LCR meters a fundamental tool or convenience tool?

[Trinity]

So, I have a basic idea of what LCR meters do, but I'm still confused as to exactly how they overlap with DMM's and other tools.

Does an LCR meter do anything that you *can't* do with a quality multimeter (say, a Fluke 87) and oscilloscope?  Or can you do everything with a DMM and scope, and it's just that an LCR meter makes it more convenient?

[Holograph]

DMMs won't do inductance and oftentimes have a more limited capacitance range than LCR meters. Also some LCR meters can test ESR which is useful for finding bad capacitors.

[ovnr]

DMMs won't do inductance and oftentimes have a more limited capacitance range than LCR meters. Also some LCR meters can test ESR which is useful for finding bad capacitors.

Actually, I happen to have a DMM that does inductance - a Meterman 37XR, used when I'm out of quality meters...
In any event, it has a resolution of 1 µH, and is completely worthless for measuring anything below 1 mH.


Anyhow: You need a LCR meter to measure ESR, Q, impedance, etc. You could probably do these with a scope and function generator, but it'd be a whole lot more work and maths! Also, most LCR meters let you set the measurement frequency, and I don't think any DMMs do that.

I highly recommend one if you already have the basics.

[jeremy]

When you realise that the simple capacitors/inductors in SPICE aren't the same as real capacitors/inductors, then it is time to buy an LCR meter.

[BravoV]

When you realise that the simple capacitors/inductors in SPICE aren't the same as real capacitors/inductors, then it is time to buy an LCR meter.

+1 , a very-very well worded reason & explanation ! 

[G0HZU]

When you realise that the simple capacitors/inductors in SPICE aren't the same as real capacitors/inductors, then it is time to buy an LCR meter.

Errr... No...

When you realise the above, it's time to throw the low frequency LCR meter in the bin.

In nearly 25 years of RF design I don't think I've ever picked up let alone used an LCR meter. I think I can say the same for my RF colleagues at work


Also, we probably have £millions of RF test gear at work but I don't think we have an LCR meter anywhere.

[Lightages]

Unless you are working constantly on crossovers and filtersthen I would say it is not very necessary nor a good buy

[Trinity]

Errr... No...

When you realise the above, it's time to throw the low frequency LCR meter in the bin.

In nearly 25 years of RF design I don't think I've ever picked up let alone used an LCR meter. I think I can say the same for my RF colleagues at work


Also, we probably have £millions of RF test gear at work but I don't think we have an LCR meter anywhere.

Is that because you don't need that functionality?  Or because you make those measurements with another tool/method?

[free_electron]

lcr meters are very useful with smd parts that have no marking... or to select mathing pairs

[Afrotechmods]

I use my LCR meter during the component selection phase of a design. I know to not trust datasheets entirely, so sometimes I will order a few different caps/inductors and check their ESR at various frequencies. I've found some real stinkers in the past. Price and performance definitely don't correlate as much as you think they should when it comes to passives.

[robrenz]

A good hand held LCR will give single milliohm resistance measurements that are far more accurate than most DMMs. They automatically eliminate Thermal emf errors because it uses AC excitation.

[Mr. Coffee]

For normal workbench testing, they are handy, but not necessary. It just depends on what kind of work you do.

[Smokey]

A decent LCR will be able to measure pure resistance way more accurately than a cheap/mid range multimeter too.  It's not just about the L and the C

[T3sl4co1l]

If you have nothing else, maybe?  Lots of things you can substitute though.  I don't have one, and on the occasions I need those sorts of measurements, I use the function generator and scope (an AC voltmeter -- if it has flat response -- might also be successfully used, for instance when resonating an inductor with a capacitor to check one or the other).

Tim

[SeanB]

Not absolutely necessary, as you can do the work using other equipment, but if you get one the convenience factor of being able to simply check a component makes it quite useful. You find you use it about as often as any other good high resolution meter.

If costs are constrained buy the $20 transistor tester in a thread here, which does a fair job of LCR as well.

[pickle9000]

Verifying components before a production run or when getting a new reel. Verifying hand wound inductors on the prototyping bench. Not a must have item but certainly worth having on the bench. I store mine without the batteries installed (so not often used).

[jeremy]

When you realise that the simple capacitors/inductors in SPICE aren't the same as real capacitors/inductors, then it is time to buy an LCR meter.

Errr... No...

When you realise the above, it's time to throw the low frequency LCR meter in the bin.

In nearly 25 years of RF design I don't think I've ever picked up let alone used an LCR meter. I think I can say the same for my RF colleagues at work


Also, we probably have £millions of RF test gear at work but I don't think we have an LCR meter anywhere.

well if we're going to go anecdote vs anecdote, 

We also have some very expensive equipment in our research lab (60GHz scope, R&S VNA, lasers that don't exist in the commercial/industrial world, etc) and we most definitely have an old but very nice HP LCR meter. It is usually connected to semiconductor probe needles for die probing.

I personally have a little BK precision LCR meter and I use it for testing ESR of caps and verifying the value of hand wound inductors.

[VK5RC]

A good lcr meter I have used mostly for Q and esr measurement but most are not testing at the frequency you really are interested,  so the results are often not directly  applicable. :-)
I think some guys are very lucky and have access to hot VNAs which make an lcr meter look very simplistic,  (me jealous,  well yes,  a lot!)

[Shock]

It's a fundamental tool if you require precision measurement accuracy.
It's a convenience tool since the ~$20 ESR meters and the ~$80 DER EE 5000 came out.

It's all about the specs, if you need more accuracy and range you need to spend more.

[madires]

I'd say a LCR meter is a fundamental tool when you're dealing with inductors, low/high value capacitors, ESR and things like Q/D. A LCR meter with Kelvin probes also allows milliohm measurements. The standard inexpensive DMM offers just the capacitance measurement, mostly only up to a few 100 or 1000µF.

[tszaboo]

It has it's uses. For service for exapmle. For design, i find it pretty useless. It is only 200Khz hameg one, and I have no circuits working that low frequency. If it would be a 10Mhz+ plotting meter from Wyne Kerr or any other high end model, that would be useful. But it is hard to justify the cost, I rather chose a part with proper characteristics in the datasheet, even if it costs more.

[Conrad Hoffman]

It depends on what you're doing. An awful lot of both design and repair work has been done successfully without an LCR meter within miles. OTOH, when I repair audio and band equipment, the LCR meter is #3 right after my DVM and scope. With the right tool you can do in-circuit measurements and spot bad caps about 80% of the time. The other 20% have to have a leg lifted. Some use an esr meter, but that only tells you half the story and doesn't correlate well to data sheets. The only LCR meter worth having will also display dissipation factor and Q. When I was doing speaker design, inductance was important. I rarely use the ac ohms feature. For tube equipment, the crown jewel for C is the GR 1617A. It can test at full bias voltage to 600 VDC and will display DC leakage. Still a bit pricey and is difficult to service.

[Wim_L]

It really depends on the situation. Sometimes, they're just what you need for a quick check that a normal multimeter can't do, or doesn't do well enough.

In other situations, a simple LCR meter is inadequate, and you'll need one that can apply a bias, or that can use uncommon frequencies to test instead of the limited set most handheld LCR meters provide. Those machines are still commonly called LCR meters, but are in a very different price category from the small handheld models.

And then there are the situations where even that isn't good enough, and a VNA is needed.

[G0HZU]

Errr... No...

When you realise the above, it's time to throw the low frequency LCR meter in the bin.

In nearly 25 years of RF design I don't think I've ever picked up let alone used an LCR meter. I think I can say the same for my RF colleagues at work


Also, we probably have £millions of RF test gear at work but I don't think we have an LCR meter anywhere.

Is that because you don't need that functionality?  Or because you make those measurements with another tool/method?

I'm mainly making the point that a typical ESR meter (eg a low frequency H/H type for beginners) isn't going to tell the user very much about the equivalent model of a component across a range of frequencies. They often test at 1kHz or 100kHz.

If I was asked to do this with minimal equipment I would expect to produce a far better wideband model of a component by measuring it using just a sense resistor, a signal source and a dual channel scope and a few simple equations in a spreadsheet.

[G0HZU]

I personally have a little BK precision LCR meter and I use it for testing ESR of caps and verifying the value of hand wound inductors.

That's fine but a typical low cost LCR meter (for beginners) isn't able to measure things like the resonant frequency of the component or the resistance or reactance at frequencies away from its test frequency.

So it isn't going to help much when trying to refine a model of the part for use in SPICE or other type of simulator. Hence my reply to this effect to your earlier post