ESR Meter

[free_electron]

hah! don't get me started on microphonics ...
You don't evenneed vibration. pulse currents trhough BaTi caps cause them to flex... the BaTi material is actually piezoelectric...
Send pulse current and the cap flexes... it can flex itself loose.... or they start singing. audibly ...
The opposite is also true. knock on the cap and it produces voltage.
The caps can pick up vibrations and inject these as electrical noise in a system !
we have that problem in harddisk. the positioning servo filter cannot use baTi based cpacitors we need Class-I as these do not have microphonic effect. the motor vibration is induced in the feedback loop of the positioning. if you have a rattling computer fan this is visible as read errors.... due to servo malfunction.

Filmcapacitors also have the microphonic pickup problem. the membrane is flexible. vibrate the cap and you get voltage out of it ( change the delta between the plates : capacitnce changes and for a given charge on the cap this translates into a voltage delta... so .. no filmcaps either...

there is so much things about components that most people do not know.
Things like voltage rating of a resistor. Noise in a resistor. why thick film is better than thin film in certain circumstances. why an l-cut trimmed part is less stable than an r-cut trimmed part.
Where noise in resistors comes from. not thermal induced noise but things like popcorn noise or flicker noise. how the resistancematerial actually causes the noise.  susumu has special lownoise SMD resistors that use a different allow than most other manufacturers. this reduces noise created by the electron flow. We use those in the servo loops.
i could go on for weeks...

[T4P]

hah! don't get me started on microphonics ...
You don't evenneed vibration. pulse currents trhough BaTi caps cause them to flex... the BaTi material is actually piezoelectric...
Send pulse current and the cap flexes... it can flex itself loose.... or they start singing. audibly ...
The opposite is also true. knock on the cap and it produces voltage.
The caps can pick up vibrations and inject these as electrical noise in a system !
we have that problem in harddisk. the positioning servo filter cannot use baTi based cpacitors we need Class-I as these do not have microphonic effect. the motor vibration is induced in the feedback loop of the positioning. if you have a rattling computer fan this is visible as read errors.... due to servo malfunction.

Filmcapacitors also have the microphonic pickup problem. the membrane is flexible. vibrate the cap and you get voltage out of it ( change the delta between the plates : capacitnce changes and for a given charge on the cap this translates into a voltage delta... so .. no filmcaps either...

there is so much things about components that most people do not know.
Things like voltage rating of a resistor. Noise in a resistor. why thick film is better than thin film in certain circumstances. why an l-cut trimmed part is less stable than an r-cut trimmed part.
Where noise in resistors comes from. not thermal induced noise but things like popcorn noise or flicker noise. how the resistancematerial actually causes the noise.  susumu has special lownoise SMD resistors that use a different allow than most other manufacturers. this reduces noise created by the electron flow. We use those in the servo loops.
i could go on for weeks...

Good read for me ! Thanks electron 
Yeah, all this while i knew about most monolithic caps are piezoelectric

[SeanB]

There are articles about how data centre drives can actually detect people singing in the racks from the increased data error rate in the drives near them, and that making the data centre quieter improves read rate considerably.

[M. András]

wow thanks the info on the topic, how much book covers it like this? i guess the handheld lcr meters arent good for design assistance too

[kripton2035]

handheld lcr meters arent able to measure at 100KHz, thay mainly stop at 10KHz
except the latest models, or the very expensive ones...

[G7PSK]

And in my ignorance I have been using ceramic capacitors and not even known what they are made of. Thanks for all the info, more learn on this thread than from any book on the subject that I have read. I will have to cut a ceramic cap open, I did this to an smd one and all I could see was a black mass and with 40X magnification a few striations in the material.

[jimmc]

It is always difficult to hold a discussion on an internet forum, misunderstandings abound. First let me say that I agree with 99.9% of all you have written, it contains a great deal of useful information not readily available.

However I cannot reconcile the quote below with the universally accepted definition of ESR based on the simple series R-C model as given in the App note I quoted.

losses in the dielectric.

losses in the dielectric are in parallel.... they are not ESR
capacitor model:

Code: [Select]

                   
            Rp
                -/\/\/\-
                     |       |
0---nnnn---/\/\/\/\--+--||---+----0

    ESL     ESR       C



Specifically the resistor labelled 'ESR' above is not what is generally understood as ESR and that the 'usual' ESR does include a portion attributable to losses in the dielectric.
Again I agree that ESR is valid only at the frequency of measurement and tells you nothing about how the capacitor behaves at other frequencies.

Jim

[free_electron]

yes and no... if you look at 'true' parameter analysers they will never measure 'ESR'.
ESR is a 'rug' you sweep losses and other 'fuzzy bits' under in an attempt to simplify things. ESR is just that. 'Equivalent'. in reality there is much more going on , but we simplify it by taking all the 'fuzzy bits' , piling them up and write down an 'equivalent' for it.

 i made a mistake in that diagram. ESR should read Rs and ESL should read Ls. brainfart on my part.

this equivalent model does not tell you everything. and during design phase the ESR is only a rough indicator. there are many other factors that need to be taken into account.

anyway

[T4P]

handheld lcr meters arent able to measure at 100KHz, thay mainly stop at 10KHz
except the latest models, or the very expensive ones...

The Mastech MS5308 is not relatively new in anyway. Few Tonghui's can do 100KHz but they are more expensive then the mastech

[robrenz]

handheld lcr meters arent able to measure at 100KHz, thay mainly stop at 10KHz
except the latest models, or the very expensive ones...

IET DE-5000  does 100kHz $330.00

[kripton2035]

DE-5000 is among the recent ones ...

[jimmc]

Thanks for your patience, I've rescaled my meter appropriately.

Jim

[CampKohler]

Thanks for taking time to write up your juicy comments, f_e. Can't read it all now, but I scraped it into a Wordpad file on my thumbdrive for later reading without having to dig back into the forum.

[typeglob]

Thanks for you posts free_electron, very interesting.

There are articles about how data centre drives can actually detect people singing in the racks from the increased data error rate in the drives near them, and that making the data centre quieter improves read rate considerably.

As for hairy men shouting at disks in a datacenter:

[StubbornGreek]

I've really enjoyed reading through this thread.

[helion]

And just like that, this thread has halted?!!

[donald]

This is ESR meter currently building , --> http://www.users.on.net/~endsodds/esr.htm

I did find postage prices steep for a "pcb" that only weigh approx 200grams or so..

[The Electrician]

yes and no... if you look at 'true' parameter analysers they will never measure 'ESR'.

What would be an example (manufacturer and model number) of a 'true' parameter analyser?

[dr_p]

handheld lcr meters arent able to measure at 100KHz, thay mainly stop at 10KHz
except the latest models, or the very expensive ones...

IET DE-5000  does 100kHz

I  have seen this on many LCR meters (IET DE-5000, Mastech MS5308, Uni-T UT612, CEM 9935, Agilent U1731): the datasheet basically says measuring large capacitors (more or less >200uF) is only done at 100Hz or 120Hz. That's 0.1kHz, just to be clear.

I understand ESR is treated as a secondary parameter so that is basically showing while measuring the capacitor. So for a large electrolytic ESR is only measured at 100Hz?

And if so, isn't that useless, since a switch-mode power supply works at 50-100kHz? 

edit:

I see that the Peak Atlas ESR meter mentions measuring ESR at 100kHz, with no mention of capacitance limitation.

[robrenz]

I just measured a 6000µf cap on the DE-5000  It will only measure the capacitance at 100Hz and 120Hz in auto range.
But when you switch to Rs for ESR you can go to 100kHz. You also get milli ohm resolution once you get to 1kHz.

Rs readings (same as ESR readings in ESR mode)
100Hz = 0.08 ohm
120Hz = 0.07 ohm
1kHz = 0.069 ohm
10kHz = 0.061 ohm
100kHz = 0.066 ohm

[dr_p]

Thanks for that, that's great to know.

But now I'm wondering if all of them do that... I guess it's all up to the main controller chip.

[T4P]

Or firmware because the MS5308 is based on the same platform and chip (NOT A COPY!)

[robrenz]

On paper the DE-5000 specs are better than the MS5308. So that makes me wonder if even though the chipset is the same are there accuracy grades of that chip and is it a higher grade chip in the DE-5000?  The fact that you can get a cal certificate from IET for the DE-5000 tells me its specs are valid and not just hype.