what's best to read ESR with a microchip ADC

[be80be]

I love https://www.taydaelectronics.com lots of goodies there.

 

[Ian Rogers]

We have Cool components and Proto pic over here!

 

[be80be]

I got most of the gunk I need in my bedroom lol figure I can't sleep may as well solder

 

[dr pepper]

I've looked at tayda burt, I think I'll be ordering some stuff rom them, have they been ok with you?

I'm fortunate enough to have an electronics shop in a seperate room, I made a bench that has a full sheet of 8' by 4' top, its mdf thats banned in your country, its a bit like smooth particleboard.

 

[MrAl]

high 5 for your formulae. ^5

Any 5V CMOS clock @50 Ohms ESR or so will work with a series R if one doesn't have a Sig. Gen.

Or Sig Gen with FM input for measuring DUT input impedance.

Getting back to OP's question, it would be easy to generate a 1MHz CMOS clock with a larger Series R as CMOS outputs are close to either 25 or 50 Ohms depending on type of CMOS, THen measure the square wave Vpp with a precision OP AMp diode rectifier with gain then input an ADC to measure the resulting square wave at a slow conversion rate.

Hi Tony,

^5 back at ya, and another ^5 for thinking of using ^5 to represent a "high five" textually.

Yeah using FM to test sounds interesting too, i'll have to look into that; interesting idea there.
One of my goals in trying to determine ESR through real world testing was to eliminate the value of C from the equation so that we get a measurement of ESR alone without interference from what the value of C might be. This might not be mandatory however, as i and others have noticed that bad caps tend to increase in capacitance as well as ESR. Maybe new caps wont follow this rule though so i thought it would be good to try to eliminate the C value so no matter what it might be or change to, we still get a good ESR reading. Interestingly, i think this is possible even at low frequency like 120Hz. Havent experimented with it yet.

 

[Tony Stewart]

My ESR meter measures at 120Hz and 10kHz, which gives slightly different readings depending on the device.

Normally it is pretty close but begins to change and include ESL.

DF at 120Hz is pretty standard and EU has to convert to 100Hz by a simple calculation as it is directly related to the tan delta which is the ratio of ESR/X(f)

CC Sine wave is the best method with auto-scaling

Interesting in large oil-filled power transformers the dielectric constant in oil is around 2 and they now have instruments ($$) to measure tan delta over a wide range of frequencies up to 10kHz and sometimes 1MHz for > 5MVA types to determine if there is any structural damage or moisture content. It's not worth testing smaller ones because the instrument is more than the transformer.

 

[The Electrician]

My ESR meter measures at 120Hz and 10kHz, which gives slightly different readings depending on the device.

What kind of meter is it? Is it homemade? If it's a commercial meter, one would think it would also measure at 1 kHz.

 

[Tony Stewart]

you are so right it was 1kHz it's a Exctech LCR 5 digit portable unit. Older version of this one which does 5 frequencies.
Test Frequency 100Hz/120Hz/1kHz/10kHz/100kHz

http://www.extech.com/instruments/product.asp?catid=56&prodid=692

Great product ! no it's fantastic... 5 digit resolution to 10 mΩ

I was thinking of a different one I used to use. (Philips)

 

[Nigel Goodwin]

What kind of meter is it? Is it homemade? If it's a commercial meter, one would think it would also measure at 1 kHz.

One would think it would measure at 100KHz, as that's the standard frequency used for ESR testing, and the value normally used to generate the values in the capacitor datasheets.

As far as actual usage goes, again it makes sense to use a high frequency, as that's similar to what the capacitors work at in SMPSU's.

 

[The Electrician]

One would think it would measure at 100KHz, as that's the standard frequency used for ESR testing, and the value normally used to generate the values in the capacitor datasheets.

As far as actual usage goes, again it makes sense to use a high frequency, as that's similar to what the capacitors work at in SMPSU's.

There are plenty of low cost LCR meters on the market that can't measure at 100 kHz, but I've never seen or heard of an LCR meter that doean't measure at 1 kHz. Even the very cheapest LCR meters that only measure at one frequency use 1 kHz as that one frequency: https://www.ebay.com/itm/DM4070-3-1...arge-2000uF-/171901097423?hash=item28061a95cf

It's very unusual for an LCR meter to not include 1 kHz; not so unusual to not include 100 kHz. Hence my surprise that Tony said his meter measured at 120 Hz and 10 kHz.

 

[Tony Stewart]

I'm sure the Ebay LCR's are worth every penny, just no comparison to the professional Extech's features.

 

[Nigel Goodwin]

It's very unusual for an LCR meter to not include 1 kHz; not so unusual to not include 100 kHz. Hence my surprise that Tony said his meter measured at 120 Hz and 10 kHz.

This thread is about ESR meters, which measure at 100KHz - for an LCR meter there isn't really any need for a specific frequency, and (assuming it uses frequencies at all) very obvious reasons for using a wide range of different ones.

 

[be80be]

Well I'm back at it LOL had a small problem with swordfish I updated to 2.2.2.5 and guess what lol Adc don't work on my chip LOL so i added the setting and tried to get it working still no adc dang I no adc worked before what the heck going on. Well some how the adc library has been changed for newer chips guess they figured no one used older chips LOL so when I build it goes ahead and removes my adc code and i never runs. So that problem figured out I should have a esr tester working today LOL

 

[Mosaic]

I have the US version to this one...works quite well.

https://www.geekbuying.com/item/Hig...5308-Handheld-Autorange-LCR-Meter-323124.html

Freqs: 100hz,1khz,10khz,100khz
Calibration port, tolerance presets for auto-binning parts, rs232 optical uplink, qfactor, ser/parallel modes

Hey Burt: ASM rules them all.

 

[be80be]

Nice metter yep asm is good just more typeing but I don't have mplab on my laptop I had to clean out the hard drive.
Never figured I'd run out of space on a 300 g hard drive lol move it to a 1 tb hard dive and installed windows 10. Lot of stuff I want to do I'm getting old. It's been six years gone by I should be getting good at programing lol I'm still hacking at it..

 

[Tony Stewart]

I have the US version to this one...works quite well.

https://www.geekbuying.com/item/Hig...5308-Handheld-Autorange-LCR-Meter-323124.html

Freqs: 100hz,1khz,10khz,100khz
Calibration port, tolerance presets for auto-binning parts, rs232 optical uplink, qfactor, ser/parallel modes

.

Those clever Chinese copied Extech's products and made them cheaper. Extech Incorporated in 1970, ASM in 1987.

 

[be80be]

Done some testing today looks good may have a pic ESR meter soon.

 

[dr pepper]

I programmed with asm till recent when I switched to C, certainly saves time, I studied c, but at the time compilers were trash compared to now.

 

[Tony Stewart]

Nice metter yep asm is good just more typeing but I don't have mplab on my laptop I had to clean out the hard drive.
Never figured I'd run out of space on a 300 g hard drive lol move it to a 1 tb hard dive and installed windows 10. Lot of stuff I want to do I'm getting old. It's been six years gone by I should be getting good at programing lol I'm still hacking at it..

I agree with Steve Gibson, No one will ever convince me to use WIN 10. IF you do, never use Express install.

 

[Mosaic]

I understand win 10 updates can reverse your privacy settings. I'll just stretch out win7 like I did with XP. I went from 95 to NT to XP to W7, skipping the rest.