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LCR meter questions and maybe recommendation.

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rwgast_lowlevellogicdesin:
Ive stepped away from hobby electronics for a while just busy work(electrician) and being a single parent, but have found myself wanting to get back in to some projects lately. I have most test equipment I need, the only thing I am missing besides a decent spectrum analyzer is an LCR meter. I was harvesting some parts the other day and realized I had no way to easily measure the IF cans I pulled. In the past when measuring inductance I have relied on one of three techniques.

#1 A common ebay TC-1 transistor/component tester
#2 Siglent SDS1104x scope controlling Siglent SDG1032x AWG@(hacked to 60mhz), that can plot I/V/phase etc etc
#3 A nanoVNA2

The TC-1 is great for a quick ballpark number as long as the tester recognizes it as an inductor and not a wire wound resistor, which is a huge problem with most inductors for RF filtering and even switching power supply design, because there inductance is to small for the TC-1 to measure. Using the scope/awg gives pretty decent results up to 60mhz but is kind of a PITA to set up. NanoVNA is also a  PITA to use to measure components because everything is has to be 50ohm and you have to build some kind of a test fixture.

After watching some reviews of handheld LCR meters I'm left with a few questions. First of all do they commonly give you the Z value at the meters selected frequency. I see that they mostly give you Q,D and X but the only one I have seen giving Z is the Peak Atlas LCR45.

Also im having a hard time understanding how useful an LCR meter is for measuring inductors you plan to use outside the frequency range outside the meter. For example if I use a calculator to wind an air core coil for a VHF filter or something can I use the LCR meter to verify the value of the coil? What about coils using iron or ferrite cores? Does the frequency a coil is driven at effect the inductance of the coil? If so that would make the meter useless for any coil being used at a frequency higher than 100khz or whatever the LCR meters top frequency is? Even a switching power supply runs at higher a frequency than the pretty standard 100khz of these meters.

tautech:
2 decades ago I was also looking at LCR meters and also getting into SMD.
I selected smart tweezers as a universal solution for both which quickly became an indispensable tool.

Much has changed and now many bench LCR devices exist yet SMD tweezers remain my tool of choice.
I highly recommend you look hard at ST42 and its record of development here:
https://www.eevblog.com/forum/testgear/design-a-new-precision-lcr-tweezers/

For more detailed info, Shannon's website might be useful also:
https://shannontweezers.github.io/docs/introduction/

shabaz:
From what you mention, probably a VNA is way more useful. Agree it's not as convenient as a couple of of alligator clips to perform a measurement, but you'll get way more satisfactory results since you're measuring at the frequency you'll actually be using it.

I have a couple of LCR meters, plus other tools that perform similar-ish operations, but I probably use the VNA more often, especially if as you say, the frequency of operation is going to be much higher.

For toroid and air core, calculations can be fairly accurate, so unless even more accuracy is needed, I might not measure and just tune in the circuit.

Sometimes I might use ready-made inductors, e.g. CoilCraft kits can be handy, they come in tolerances like 2.5%. I have no issue constructing DIY inductors, and keep various ferrites and iron cores handy. For typical HF/VHF work, software like Coil64 is as accurate as is practically possible without electromagnetic simulation tools I think - I've had a good experience with that software.

Martin72:

--- Quote from: tautech on June 02, 2024, 09:13:33 pm ---2 decades ago I was also looking at LCR meters and also getting into SMD.
I selected smart tweezers as a universal solution for both which quickly became an indispensable tool.

Much has changed and now many bench LCR devices exist yet SMD tweezers remain my tool of choice.
I highly recommend you look hard at ST42 and its record of development here:
https://www.eevblog.com/forum/testgear/design-a-new-precision-lcr-tweezers/

For more detailed info, Shannon's website might be useful also:
https://shannontweezers.github.io/docs/introduction/

--- End quote ---

For the applications he has outlined, the tweezers can only be considered as a supplement.
Or I would only get them as a supplement, not for everything, the maximum frequency alone is too low for that.

nctnico:
You need multiple instruments. An LCR meter is OK for determining inductance. For an inductor with a core, it is nice to be able to have current flowing through it so you can measure the saturation point. A VNA is a good instrument to measure the self resonance frequency of an inductor.

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