Author Topic: do i really need an expensive LCR meter??  (Read 980 times)

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Offline e0ne199

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do i really need an expensive LCR meter??
« on: September 27, 2020, 01:51:56 am »
hello everyone... i am sorry i am asking you all about this trivial (and probably stupid to some of you) question, because i am still very newbie about this.. forgive me if i am wrong  ;D
i have already had de-5000 that i purchased last year, but i have a question... does LCR meter like de-5000 cover every application involving capacitor and inductor?? if not, what kind of application is an expensive LCR meter suitable for?
any answer is appreciated  :popcorn:
 

Online blueskull

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Re: do i really need an expensive LCR meter??
« Reply #1 on: September 27, 2020, 02:00:46 am »
Depending on how extreme are you going with.

If you are after characterizing LCR at a bias current and/or voltage, then you need to build and calibrate-out a bias injection jig.

If you want it to be built for you, you need a much more expensive unit, like E4980A with some options -- and it only injects voltage, not current. To inject current, you need to invest more on third party jigs.

If you are after dynamic LCR at a certain excitation waveform, you need a (potentially high power) resonant tester, an those things are basically only built to orders. Expect high $4-digit to low $5-digit.

Also if you need to measure extremely low inductance or capacitance, you need a VNA, not an LCR meter, and some RF knowledge like impedance matching and transmission line & test jig calibration.

For me, the majority of the time I measure inductance is with a VNA since most of the time I work in the sub-nH to 10nH range, but that's a very niche field and most people would never need to do that.

For common everyday use, I have an LCR tweezers.
 

Offline coromonadalix

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Re: do i really need an expensive LCR meter??
« Reply #2 on: September 27, 2020, 02:01:35 am »
normally a good lcr can or could do  serial or parallel testing,  but it will depend of the circuit in witch you will probe

up to 100khz frequency test is okay for  many scenarios

of course the use of kelvin probe help a lot

annnd he list goes on and on  like blueskull wrote
 

Offline bob91343

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Re: do i really need an expensive LCR meter??
« Reply #3 on: September 27, 2020, 02:15:19 am »
The original post made me chuckle.  I have lots of LCR meters and which I use depends on the application.  Measuring a capacitor at 1000 Hz will give different results from measuring it at 100 MHz.  Accuracy is sometimes more important.  Leakage too, and ESR and ESL and self resonant frequency.  And that's just for capacitors.

Inductors are much more tricky.  Resistors not so much but still there are plenty of considerations that need attention.

Of course bias is another issue that I won't deal with here.

The short answer is that you need a measuring device that corresponds to the application.
 

Offline coromonadalix

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Re: do i really need an expensive LCR meter??
« Reply #4 on: September 27, 2020, 02:43:11 am »
+1  :-+
 

Online TimFox

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Re: do i really need an expensive LCR meter??
« Reply #5 on: September 27, 2020, 02:47:28 am »
The most important point is that raised by Bob91343.  The DE-5000 is good in the audio range, but for RF applications there are other instruments that work well above 100 kHz.
 

Offline e0ne199

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Re: do i really need an expensive LCR meter??
« Reply #6 on: September 27, 2020, 10:59:35 am »
haha thank you so much for your explanation here  ;D
at least i get some enlightment about the importance of expensive LCR meter 😀
i mostly work on digital electronics, and perhaps analog on basic level... again thank you so much for your explanation here  ;D
 

Online TimFox

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Re: do i really need an expensive LCR meter??
« Reply #7 on: September 27, 2020, 02:00:59 pm »
Things that go wrong with "digital" circuits are often "analog" in nature.  For example, if you need to measure the self-resonant frequency of a bypass capacitor, a high-frequency unit with very careful fixturing is required.
 

Online David Hess

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Re: do i really need an expensive LCR meter??
« Reply #8 on: September 28, 2020, 04:03:20 pm »
i have already had de-5000 that i purchased last year, but i have a question... does LCR meter like de-5000 cover every application involving capacitor and inductor?? if not, what kind of application is an expensive LCR meter suitable for?

Network analyzers give much more detailed information by essentially testing at every frequency.  I have had decoupling capacitors which tested good at low frequencies but were in fact bad.

LCR meters do not measure leakage or dielectric absorption in capacitors, or saturation or hysteresis in inductors, which are important in some applications.  Blueskull mentioned voltage coefficient of capacitance.

 

Offline bob91343

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Re: do i really need an expensive LCR meter??
« Reply #9 on: September 28, 2020, 05:18:27 pm »
This brings me to one of my favorite topics, the nanoVNA. It measures capacitance and inductance and resistance and much more over an amazing frequency range.  It showed me how ineffectual an electrolytic capacitor is at high frequency.  It showed me the effect of lead length on components of all sorts.

I have learned more from this little cheap device than from nearly any other test equipment I have used.
 

Online tggzzz

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Re: do i really need an expensive LCR meter??
« Reply #10 on: September 28, 2020, 05:26:08 pm »
haha thank you so much for your explanation here  ;D
at least i get some enlightment about the importance of expensive LCR meter 😀
i mostly work on digital electronics, and perhaps analog on basic level... again thank you so much for your explanation here  ;D

You are actually working on analogue electronics. Exception: if you are working on photon-counting or femtoamp circuits :)

Whatever equipment you use, you have to understand how the measurement results do and do not relate to your circuit.

So, first understand and define what is important in your circuit, and second find a way of measuring that.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Online Martin72

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Re: do i really need an expensive LCR meter??
« Reply #11 on: September 28, 2020, 08:16:28 pm »
Hi,
Quote
Inductors are much more tricky.

For inductance measure we use three methods, depending on the DUT.

Generally we use a GenRad LCR/Keysight LC1733C, for the most situations.(The DE-5000 matches their results very close/identical, so I´m happy to have one for private use).
When the airgap of a coil must be adjusted, we use a parallel resonant circuit with known capacitor.
For powercoils we use a selfmade device which can deliver pulses up to 200A, calculating the inductance by an µC.( so was the intention, but most we´re using a scope parallel, because of the ringing)



Offline wizard69

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Re: do i really need an expensive LCR meter??
« Reply #12 on: September 29, 2020, 06:55:05 pm »
Bob above probably gave the best answer.    I look it this way, everybody should have at least one good hand portable multimeter but that doesn't mean you will not want to have a good bench meter at some point in time.  Even on the bench having more than one bench meter may make sense as they are not all the same and sometime you just need to monitor more than one node.   

So a LCR meter like the DE-5000 is a good start.   At some point in your knowledge expansion and challenges you will realize that you need something different and even have a good idea what the features will be on such a device.

Think of it this way; if you buy a 100 MHz scope and at a latter date pick up a wiz bang 1Ghz scope, that 1GHz scope doesn't make the old scope useless.   On the contrary you might reach for that 100MHz scope more often as a general purpose unit.   It really depends upon your needs which by the way can change over time or for some stay the same.   If you are focused on audio equipment for example you might setup a repair / build bench and never have a need for new equipment for years.

hello everyone... i am sorry i am asking you all about this trivial (and probably stupid to some of you) question, because i am still very newbie about this.. forgive me if i am wrong  ;D
i have already had de-5000 that i purchased last year, but i have a question... does LCR meter like de-5000 cover every application involving capacitor and inductor?? if not, what kind of application is an expensive LCR meter suitable for?
any answer is appreciated  :popcorn:
 


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