ESR meter 200kHz

[tigr]

Measurement ESR of capacitors:electrolytics,films,ceramics,polymer.
ESR-0,001-30Ohm
F-200kHz
Ut-100mV
VD1,VD2-1N4007
VD3-VD6-1N5819
C2-2,2uF/63v(film)
R2-0,18Ohm
R5-100k
C3(removed)
T1 1-40/2-200
PA1-0,05-0,1mA
U-5v

[hugo]

Hi Tigr,

What is the benefit of using 200kHz instead of the more traditional 100KHz ?
What kind of transformer is T1 " T1 1-40/2-200" ?
R2-0,18 Ohm that is not right to me ...

Thanks

[tigr]

Hi hugo.
This frequency is chosen because the circuit working at this frequency. The transformer can be wound with a wire of 0.1-0.15 mm or use a ready one. The resistor R2 can be used 5-0.05 Ohm.
Transformer from my latest version.Removed from some power supple.The ratio of the windings is 1:40.The wire is 0,3mm.
R5-100k

[tigr]

Microammeter. You can use different.
50u-100uA.

[tigr]

Measurement ESR of capacitors:electrolytics,films,ceramics,polymer.

[tigr]

The main feature of this ESR meter is the search for faulty film capacitors of low capacitance in the circuit.

[tigr]

About ESR.
https://www.allaboutcircuits.com/technical-articles/determining-equivalent-series-resistance-esr-of-capacitors/

[tigr]

Experimental version for ESR 350kHz for ceramic capacitors.
Transformer from the old Sony TV.

[tigr]

Using Tweezers MAX 253, you can measure esr of capacitors of large capacitance.
Capacitors MKT-15uF.
ESR~0,001Ohm.

[b_force]

Hi Tigr,

What is the benefit of using 200kHz instead of the more traditional 100KHz ?
What kind of transformer is T1 " T1 1-40/2-200" ?
R2-0,18 Ohm that is not right to me ...

Thanks

Better sweep a range from a few hertz to a few Mhz to get the total impedance.
Why? To get a better idea how capacitors perform at certain frequencies.
I have seen caps that worked great around 100kHzish, but failed bad if you would go somewhat higher.

[tigr]

More examples of the measurement of ESR for high-capacity film capacitors.

[tigr]

What is the benefit of using 200kHz instead of the more traditional 100KHz ?

The difference in ESR at these frequencies is minimal.

[b_force]

What is the benefit of using 200kHz instead of the more traditional 100KHz ?

The difference in ESR at these frequencies is minimal.

Well, the impedance is clearly different.
Also really depends what kind of capacitor you have.
I have seen (and used) ones that are much worse (also much better)

[tigr]

In datasheets for polymer capacitors, only indicate the ESR at a frequency of 100-300kHz.

[tigr]

The quality of the dielectric of film capacitors depends on the ESR. This can be verified by measuring different capacitors of 100nF.

[tigr]

The inductance of the windings of the transformer is 200 kHz.

[tigr]

Tweezers Max 253 always helps in complex cases of measurements in the circuit.
 The computer power supply. The capacitor is 2200 mkF 10V.
ESR-0,008Ohm.

[ocw]

Have I missed the accuracy verification?  All of these numbers are nice but if they are not accurate they are meaningless.

Right now I'm testing an economy Ragu 17B multi-meter that I've just received.  For resistance accuracy verification I'm using 0.01% accuracy resistors that range in value of 10 ohms to 10M ohms.  For resistances below 10 ohm I'm using 0.05 or 0.1% accuracy resistors.

[tigr]

And the resistor 0.001 Ohm 1% is not enough? Something I have not seen anywhere, that this resistor was checked by the ESR meter.
They correctly show the measurement of resistors 0.001 Ohm and 0.01 Ohm.
Resistor 0,001Ohm 1%.

[ocw]

And the resistor 0.001 Ohm 1% is not enough?

That reading looks believable.  Sorry.  I hope that your ESR meters and your 200 kHz tests show the same thing.  Two wire readings of a fraction of an ohm to an analog meter have me wondering though.

[tigr]

Resistor 0,001Ohm 1%.

[The Electrician]

More examples of the measurement of ESR for high-capacity film capacitors.

I very much doubt that the Epcos 15 uF MKT capacitor shown here could have an ESR as low as .001 ohms.

See the data for this capacitor here: https://en.tdk.eu/inf/20/20/db/fc_2009/B32520_529.pdf

On page 21 we see that the typical ESR for a 15 uF capacitor is about .01 ohms, not .001 ohms.

I have no doubt that your meter can measure .001 ohms for a pure resistor, but not for a real capacitor.

If I correctly read the schematic in post #1, the circuit of your meter has no phase sensitive detector so it is measuring the magnitude of the impedance (|Z|) of a capacitor, not the real part of the impedance which is the ESR.

[tigr]

If I correctly read the schematic in post #1, the circuit of your meter has no phase sensitive detector so it is measuring the magnitude of the impedance (|Z|) of a capacitor, not the real part of the impedance which is the ESR.

Everything perfectly measures.
The polymer capacitor OS-CON SVP 820uF/6,3V ESR(max.)-0,012Ohm.
http://uk.farnell.com/panasonic-electronic-components/6svp820m/cap-alu-elec-820uf-6-3v-smd/dp/2354726
Tweezers MAX253.ESR~0,007Ohm.
More accurately.
Tweezers ESR-TIGR.ESR-0,0065Ohm.

[The Electrician]

If I correctly read the schematic in post #1, the circuit of your meter has no phase sensitive detector so it is measuring the magnitude of the impedance (|Z|) of a capacitor, not the real part of the impedance which is the ESR.

Everything perfectly measures.
The polymer capacitor OS-CON SVP 820uF/6,3V ESR(max.)-0,012Ohm.
http://uk.farnell.com/panasonic-electronic-components/6svp820m/cap-alu-elec-820uf-6-3v-smd/dp/2354726
Tweezers MAX253.ESR~0,007Ohm.
More accurately.
Tweezers ESR-TIGR.ESR-0,0065Ohm.

It is entirely possible for a meter than doesn't have a phase sensitive detector to correctly measure the ESR of a capacitor if the capacitor is rather lossy.  This is because at frequencies near the self resonant frequency of the capacitor, the impedance (Z) is essentially the same as the real part (Rs) of the impedance.  This is because the curve of impedance versus frequency has a broad minimum, as shown in your image in post #11.  I explain this here: https://www.eevblog.com/forum/projects/impedance-lcr-esr-meters/msg459262/#msg459262 and in the posts following.

But when measuring a low loss film capacitor, the curve of impedance versus frequency has a sharp minimum like this:



The ESR is equal to the impedance at the very bottom of the sharp impedance versus frequency curve, and if the measurement of your meter is at that frequency, then it will measure the ESR; otherwise, it will measure the impedance which will be larger than the ESR.

So, to summarize, a meter that measures impedance (Z) rather than ESR will do what is wanted if you are measuring lossy capacitors such as electrolytics and if your measuring frequency is around 100 kHz plus or minus a bit, but it may read too high with film capacitors.

[The Electrician]

How do you answer the objection I raised about the 15 uF MKT capacitor that your meter showed has an ESR of .001 ohms? I said:

"I very much doubt that the Epcos 15 uF MKT capacitor shown here could have an ESR as low as .001 ohms.

See the data for this capacitor here: https://en.tdk.eu/inf/20/20/db/fc_2009/B32520_529.pdf

On page 21 we see that the typical ESR for a 15 uF capacitor is about .01 ohms, not .001 ohms."

[tigr]

How do you answer the objection I raised about the 15 uF MKT capacitor that your meter showed has an ESR of .001 ohms? I said:
"I very much doubt that the Epcos 15 uF MKT capacitor shown here could have an ESR as low as .001 ohms.

I fully agree with you. This ESR meter was not developed for the measurement of ESR for film capacitors.

[Jay_Diddy_B]

Hi group,

Here is a message reproduced from this thread:

https://www.eevblog.com/forum/projects/esr-meter-adapter-design-and-construction/

In this message I measure a Film capacitor with a HP 4274A LCR meter and compare the measurements against a relatively simple ESR meter that uses a phase sensitive detector. The ESR meter adapter is able to measure a result that is lower than the impedance of the capacitor but not accurate.

Hi,

I have also done some testing with a film capacitor. I do not have the 'official' 6.8uF film capacitor. I used a 4.7uF 250V Metalized polypropylene film capacitor.

Here is a picture of the capacitor used for test:



This is has an extremely low ESR. I first measured the capacitor using my HP4274A LCR meter with a HP 16047A test fixture. Here are the measurements:



Note: That the device impedance is very reactive, >89.6 degrees at 100 kHz

Here a couple of sample pictures of the measurements:







When I connected the capacitor to the ESR adapter using the 4W configuration, I zeroed the meter using the relative feature on  the DMM.
I measured 5.355mV which corresponds to 53 m Ohms.



This is 0.26% of the ESR meter adapters full scale, and significantly lower than the impedance of the capacitor 340.7 m Ohms.





Observations

1) The HP4274A with a four terminal test fixture, and short & open calibration, is able to read ESR values in the 1 to 2 m region.

2) The film capacitor ESR is very low. I looked for an impedance curve, but I couldn't find one.

Regards,

Jay_Diddy_B

[The Electrician]

Jay_Diddy_B,

   Do you have the manual for the 4274?  Looking in my old 1988 HP catalog, the specs for the 4274 show the measurement range for ESR is 100 milliohms to 10 megohms.  I wonder how much trust can we put in a measurement for ESR of 1 or 2 milliohms?

   I have been thinking for some time about how we could get a truly accurate measurement of very low ESR in the sub-MHz frequency range.

   For high RF the resonant line technique can give 1 milliohm accuracy, but how to do it at 10 KHz?

   The problem is that if the real part of the impedance of a capacitor is R ohms, when the reactive part is 1000*R the measurement becomes difficult.  For your 10 KHz measurement, the ratio of |Z| to Rs is about 3000.

   I notice that for ratios over 1000, the meaurement on my various meters becomes noisy.  I should dig out an appropriate capacitor, measure it very carefully, and mail it to you for comparison.

   But, what we really need to do is find a special technique making the measurement where phase angle of the impedance is very near 90 degrees.

   In the case of all these measurements tigr is making, he has no independent way of verifying his measurements--he is assuming that the ESR he measures is correct.  He should mail me some of his capacitors, or I should mail him some that I have measured.

[Jay_Diddy_B]

Jay_Diddy_B,

   Do you have the manual for the 4274?  Looking in my old 1988 HP catalog, the specs for the 4274 show the measurement range for ESR is 100 milliohms to 10 megohms.  I wonder how much trust can we put in a measurement for ESR of 1 or 2 milliohms?

   I have been thinking for some time about how we could get a truly accurate measurement of very low ESR in the sub-MHz frequency range.

   For high RF the resonant line technique can give 1 milliohm accuracy, but how to do it at 10 KHz?

   The problem is that if the real part of the impedance of a capacitor is R ohms, when the reactive part is 1000*R the measurement becomes difficult.  For your 10 KHz measurement, the ratio of |Z| to Rs is about 3000.

   I notice that for ratios over 1000, the meaurement on my various meters becomes noisy.  I should dig out an appropriate capacitor, measure it very carefully, and mail it to you for comparison.

   But, what we really need to do is find a special technique making the measurement where phase angle of the impedance is very near 90 degrees.

   In the case of all these measurements tigr is making, he has no independent way of verifying his measurements--he is assuming that the ESR he measures is correct.  He should mail me some of his capacitors, or I should mail him some that I have measured.

I am not sure about the accuracy. The nice thing about the HP4274A is that it can display the impedance as a magnitude and angle. This gives a good indication of how hard it is to do the measurement.

I have some low value resistors, single digit milliohms, that I could place in series with the film capacitor to check the calibration.

I also have a VNA and perform an impedance sweep.

Let me play in the lab and will report back with some measurements.

Regards,

Jay_Diddy_B

[Jay_Diddy_B]

Hi Electrician and the group,

I believe that this is the chart you are looking for:



This from the manual, available here:

https://www.doe.carleton.ca/~nagui/labequip/lcr/4274A_Operating%20Manual.pdf

Regards,
Jay_Diddy_B

[Jay_Diddy_B]

Hi group,

Here are a few tests made with the HP 4274A. This is a different capacitor than I used in the previous posting.

Packaging



The decoder



The test sample



A test sample was prepared with a 5m resistor soldered to one of the leads. The lead behind the capacitor will be cut in later tests.

Baseline Measurement



With the 5m resistor in series




And then two capacitors in series



This is a very good test, because the capacitance should be half and the ESR double. These capacitors when measured individually were about 17m each.

I had to the open and short cal several times, the instrument was warming up.

I believe that these are pretty good results.

Regards,

Jay_Diddy_B

[tigr]

Hi Jay_Diddy_B
Thanks for the table. It explains the whole point of the problem.
The main problem with all ESR meters is the ability to separate the active and reactive components from the capacitor.This depends on many factors,and primarily on the measurement method.In practice,most amateur circuits are not situable for measuring the ESR the film capacitors.After many experiments_the scheme of the universal ESR meter  was chosen for practically all types of capacitors.
I want to tell you that the main purpose of my work on the measurement of ESR is the ability to measure with maximum accuracy the ESR of the capacitors in the circuit and the analysis of the circuit in which the capacitor is located. The second task is to analyze the effect of other elements in the capacitor circuit. I'm glad to hear useful advice and thoughts from different specialists.

[Jay_Diddy_B]

Tigr and the group,

By far the best results I have obtained have been with a VNA (HP 3577A) and a homemade transconductance amplifier.

The setup is calibrated with a 1 resistor. This means all the amplitude reading are in dB .

Here is an electrolytic capacitor 100kHz to 1MHz



The marker is -17dB = 140m . You can see the ESL causing the impedance to rise at higher frequencies.


Here is a ceramic capacitor 100 kHz to 10MHz



The marker is at -44dB = 6.3m

Regards,

Jay_Diddy_B

[The Electrician]

Jay_Diddy_B,

   These measurements are what I would expect with a polyester cap.

   The older measurements where you were getting 1 milliohm values was with a metalized polypropylene if I remember correctly.  Do you still have that capacitor so the result could be rechecked?

[The Electrician]

I've set up an impedance analyzer (Hioki IM3570) to perform a frequency sweep from 100 Hz to 1 MHz, displaying impedance magnitude (|Z|) in green and ESR (Rs) in yelllow.  The first sweep is of a precision .02 ohm resistor; the top of the screen is at .1 ohms and the bottom at .001 ohms:



Both |Z| and ESR are right on .02 ohms until at the high frequency end of the sweep |Z| rises do to the inductance of the resistor leads.

Here's a sweep of a really good polypropylene 5 uF capacitor, using the ordinary settings for the analyzer; the top of the screen is changed to 1000 ohms.  Notice that the ESR curve at the low frequency end of the sweep is noisy; the ratio of |Z| to ESR is 4 orders of magnitude, making this a difficult measurement:



By using some averaging, the ESR curve is cleaned up at the low frequency end:



Here is the same capacitor, but with the top of the screen changed to .1 ohms:



Notice that there's a downward jump in the ESR curve (yellow).  This is due to the range change that occurs during the sweep; the instrument needs to go in for calibration.  The question is, which part of the curve is accurate, the left side before the jump or the right side.  I measured this same capacitor on a Wayne-Kerr analyzer and determined that the right side is accurate.

The lowest ESR is around 3 milliohms at around 3 KHz.  I get the same values on other analyzers.

I would like to mail this capacitor to you, Jay_Diddy_B.  If you're interested PM me a good mailing address.

Just for reference, here's a sweep of a Polyester (MKT) capacitor.  The lowest ESR is nowhere near .001 ohms.  It has been my experience that Polypropylene caps have the lowest ESR, much lower than Polyester caps:

[tigr]

Hi,

I have also done some testing with a film capacitor. I do not have the 'official' 6.8uF film capacitor. I used a 4.7uF 250V Metalized polypropylene film capacitor.

Here is a picture of the capacitor used for test:



This is has an extremely low ESR. I first measured the capacitor using my HP4274A LCR meter with a HP 16047A test fixture. Here are the measurements:



Note: That the device impedance is very reactive, >89.6 degrees at 100 kHz

Here a couple of sample pictures of the measurements:







When I connected the capacitor to the ESR adapter using the 4W configuration, I zeroed the meter using the relative feature on  the DMM.
I measured 5.355mV which corresponds to 53 m Ohms.



This is 0.26% of the ESR meter adapters full scale, and significantly lower than the impedance of the capacitor 340.7 m Ohms.

It would be interesting to see what your device will show if you connect these three capacitors in parallel.

[tigr]

Good film capacitors for testing ESR meters .
http://www.mouser.com/ds/2/427/mkp1848dcl-35623.pdf
It is possible to significantly increase the accuracy of the measurement of ESR in film capacitors by expanding the dynamic range of the measurement. For this we connect the meter to a voltmeter. The measurement takes place in millivolts. The value of 550 mV corresponds to zero ESR.In our case, the full scale is 550 mV. The values after calibration can be recorded, they are easily remembered with time.

[tigr]

Using an extended measuring range, we obtain an in-circuit circuit analyzer,capable of distinguishing low shunt resistance from abnormally LOW ESR, short circuit and ESR parallel connection of capacitors.
Motherboard.Capacitor 3300uF/6,3v.

[Jay_Diddy_B]

Tigr,

These images that show with the Amprobe DMM, what circuit is being used to drive the meter?

Regards,

Jay_Diddy_B

[tigr]

ESR meter 200kHz.

[tigr]

With this device it is also possible to check small coils for winding breakage. If the coil is OK, then the device can approximately estimate its inductive resistance. When the coil breaks, the device will show the maximum resistance.
All this can be done without removing the coil.

[Jay_Diddy_B]

Hi Tigr and the group,

I have done a little simulation on the circuit that is proposed by Tigr. There is no model in LTspice for the MAX253, so it was replaced by a simplification. I am stepping the value of the resistor through a series of resistors. I am plotting the output voltage versus Resr. This is gives you an indication of the meter reading (deflection).

LTspice model



LTspice modelling Results




In doing the analysis, I released that the MAX253 can be replaced by the 555 timer:



Results 555 timer version



Observation

The meter deflection is very similar to the 5 transistor ESR meter that I shared in this thread:

https://www.eevblog.com/forum/projects/5-transistor-esr-meter-design/msg171364/#msg171364

This is the results from modeling the 5 transistor circuit:





I have attached the LTspice models for those playing along at home.

Regards,

Jay_Diddy_B

[tigr]

Hi Jay_Diddy_B,
Your scale is 0.1-10 Ohm. My scale is 0.001-30 Ohm.
 Your meter will show that the electrolytic capacitor 1uF/450v is a bad capacitor.

[tigr]

For example.New capacitors.
Nichicon 1uF/450v.ESR-11Ohm.
1uF/450v.ESR-19,6Ohm.

[ocw]

You can increase many ESR meter's resolution by using the Q that it measures to then compute the ESR.  An example of that is below:

ECW-F4105HL  1uF 400V #2
   Measured capacitance:  1.0140 uF
   Measured ESR:  0.00 ohms
   Measured Q:  1832
   Calculated ESR:  0.0008568 ohms  (Xc/Q)

All of the above measurements were taken at 100 kHz.  Additional examples of this are shown on the attachment.

[tigr]

Hi ocw.
Thanks.
Tweezers MAX253 350kHz for in-circuit detection of faulty capacitors.
The full scale is 1000mV.
A good capacitor.

[The Electrician]

You can increase many ESR meter's resolution by using the Q that it measures to then compute the ESR.  An example of that is below:

ECW-F4105HL  1uF 400V #2
   Measured capacitance:  1.0140 uF
   Measured ESR:  0.00 ohms
   Measured Q:  1832
   Calculated ESR:  0.0008568 ohms  (Xc/Q)

All of the above measurements were taken at 100 kHz.  Additional examples of this are shown on the attachment.

Be aware that just because the meter gives you a number doesn't mean that it's accurate.

Here's the Panasonic info for the ECW-F4105HL: https://industrial.panasonic.com/ww/products/capacitors/film-capacitors/film-cap-electroequip/ecwfl/ECWF4105HL

On that page we see a link to the catalog page: https://industrial.panasonic.com/cdbs/www-data/pdf/RDI0000/ABD0000C245.pdf

The catalog page doesn't show the ESR directly, but it does give a maximum spec for the dissipation factor Tan delta.

On the first page linked above we see a link to "Temperature characteristics, permissible current and others": https://industrial.panasonic.com/cdbs/www-data/pdf/RDI0000/ABD0000COS29.pdf

That page doesn't list ESR directly, but there is a graph that gives us an idea what the ESR for a 1 uF cap might be:



The sharp bottom of the impedance curves is the ESR at the particular frequency.  Imagine what the curve would look like for a 1 uF cap.  It would be a little to the left of the .47 uF curve, and the ESR would be perhaps 20 milliohms.  It's very unlikely that the ESR of an ECW-F4105HL 1 uF cap would be less than 1 milliohm.

[ocw]

Be aware that just because the meter gives you a number doesn't mean that it's accurate.

That's true particularly when you are getting to the extremes of measurement.  However, my measurements of the other capacitors are not far off the measurements of the same capacitors by Jay_Diddy_B and his HP meter.  That is why I included those model capacitors.

As far as the ECW-F4105HL goes, Panasonic's information is generic, not for a particular capacitance value.  They say a DF of 0.05% at 1 kHz (Q = 2000) and a DF of 0.20% at 10 kHz (Q = 500).  I would assume that those are worst case figures for the capacitor value having the worst DF.  Given the other measurements, those for the ECW-F4105HL don't look too far out of line.  My calculated values might not be precisely accurate, but should be accurate as far as the ESR being definitely lower than the other models tested.

I also tested their ESR from 10 kHz to 100 MHz (I could have gone higher) using other equipment but didn't include that data since it didn't have much better ESR resolution.

[ocw]

I forgot to add, my attachment shows the ESR of one of those ECW-F4105HL capacitors by itself and then with a precision 0.2003 ohm resistor in series with it.

[tigr]

The main problem with all ESR meters is the ability to separate the active and reactive components from the capacitor.This depends on many factors,and primarily on the measurement method.In practice,most amateur circuits are not situable for measuring the ESR the film capacitors.

I will demonstrate using an example of a super-quality polystyrene capacitor 0.5 uF 250V 1%.

[tigr]

Another serious problem with the ESR meters is related to the measurement of electrolytic s of less than 1 uF. In the ESR tables, these values are not available.

[The Electrician]

The main problem with all ESR meters is the ability to separate the active and reactive components from the capacitor.This depends on many factors,and primarily on the measurement method.In practice,most amateur circuits are not situable for measuring the ESR the film capacitors.

I will demonstrate using an example of a super-quality polystyrene capacitor 0.5 uF 250V 1%.

Exactly what are you demonstrating here? I see that there is considerable difference in the first two ESR measurements, and I don't know what the reading in the third measurement is.

It is to be expected that when measuring ESR using the pulse or square wave technique that the result will not be accurate when, at the frequency of measurement, the impedance of the capacitor is much larger than the ESR.  In that case the only way to get a good measurement is to use sine wave excitation.

There are some relatively low cost meters that use sine wave excitation, such as the DE-5000.  Do you have any meters that use sine wave excitation?

[ocw]

Do you have any meters that use sine wave excitation?

Attached is the 100 kHz capacitor evaluation waveform from my Extech LCR200.
The other test frequencies are similar sine wave signals.

[tigr]

and I don't know what the reading in the third measurement is.

0,005Ohm.
And where it is possible to read about the effect of the shape of the measuring signal on the measurement of ESR, tested in practice?

[ocw]

Do you have any meters that use sine wave excitation?

I should have also included the attached 100 MHz test signal that I use for capacitor evaluation from my AIMUHF analyzer.  It can test up to 1 GHz although eliminating the effects of the test "cable" becomes more difficult above 500 MHz.

[Jay_Diddy_B]

Exactly what are you demonstrating here? I see that there is considerable difference in the first two ESR measurements, and I don't know what the reading in the third measurement is.

It is to be expected that when measuring ESR using the pulse or square wave technique that the result will not be accurate when, at the frequency of measurement, the impedance of the capacitor is much larger than the ESR.  In that case the only way to get a good measurement is to use sine wave excitation.

There are some relatively low cost meters that use sine wave excitation, such as the DE-5000.  Do you have any meters that use sine wave excitation?

1+

I don't see anything in Tigr's design that is revolutionary or offers any significant improvements.

The design can be simplified a current source, a standard resistor and a current detector:



The MAX253 and the resistor form a current source. The current is split between a resistor, which I will call the standard resistor and the impedance of the capacitor being tested. The current through the capacitor under test is measured and displayed.

The meter will read a maximum if the impedance of the capacitor is zero. The meter will read half-scale if the impedance of the capacitor is equal to the standard resistor.

The impedance of the capacitor consists of three parts, the capacitance, the ESR and inductance.

The impedance is only equal to the ESR if 1/(2 x pi x Freq x C) = 2 x pi x Freq x L

So if the frequency is swept the results are:



Sweeping the value of C

If change the model. I have fixed the frequency at 300 kHz and I am sweeping the value of capacitance. I am measuring the RMS current in the capacitor under test.



Results with Resr = 10m



Results with Resr = 200m




The desirable result is to have the ESR reading independent of the value of the capacitor.

All this shows that it not possible to accurately measure the ESR of capacitor by simply measuring the impedance.

You need to also measure the phase angle or use a phase sensitive detector that measure the component of the impedance that is in-phase with excitation current.

The ESR adapter that I shared here:

https://www.eevblog.com/forum/projects/esr-meter-adapter-design-and-construction/msg341177/#msg341177

This circuit uses a phase sensitive detector, which helps but it is not super accurate for low values of capacitance.

I have attached the LTspice models for those playing along at home.

The best DIY solution I have seen was done by Jaxbird:



https://www.eevblog.com/forum/projects/impedance-analyzer-build-and-experiments/

Unfortunately, some of the pictures are lost.


Regards,

Jay_Diddy_B

[tigr]

  In that case the only way to get a good measurement is to use sine wave excitation.

I once was interested in this issue,but in practice I never saw the difference.

[The Electrician]

and I don't know what the reading in the third measurement is.

0,005Ohm.
And where it is possible to read about the effect of the shape of the measuring signal on the measurement of ESR, tested in practice?

I explain it in reply #6, reply #7 and reply #8 of this thread: https://www.eevblog.com/forum/projects/impedance-lcr-esr-meters/msg459262/#msg459262

[tigr]

All this shows that it not possible to accurately measure the ESR of capacitor by simply measuring the impedance.
You need to also measure the phase angle or use a phase sensitive detector that measure the component of the impedance that is in-phase with excitation current.

For me, a simple practical criterion is important, when the result of the measurement is less than that indicated in the datasheet. This means that the device measures the real ESR.
Capacitor LOW ESR Rubycon MBZ 3300uF/6,3v.By datasheet max.ESR-0,012Ohm.
The ESR meter is with a synchronous detector. Measures a practically pure ESR. The result is in the table.
 My ESR meter shows 0.006 Ohm. Which sensitive detector is needed?

[tigr]

There are some relatively low cost meters that use sine wave excitation, such as the DE-5000.

I do not use instruments that give the same result of ESR at different frequencies.
Your topic was reading. Thanks.

[The Electrician]

All this shows that it not possible to accurately measure the ESR of capacitor by simply measuring the impedance.
You need to also measure the phase angle or use a phase sensitive detector that measure the component of the impedance that is in-phase with excitation current.

For me, a simple practical criterion is important, when the result of the measurement is less than that indicated in the datasheet. This means that the device measures the real ESR.
Capacitor LOW ESR Rubycon MBZ 3300uF/6,3v.By datasheet max.ESR-0,012Ohm.
The meter is with a synchronous detector. Measures a practically pure ESR. The result is in the table.
 My meter shows 0.006 Ohm. Which sensitive detector is needed?

Jay_Diddy_B was not talking about a capacitor with 3300 uF; he was talking about much smaller value capacitors.

I don't have a 3300 uF Rubycon, but I do have a 1800 uF 6.3 volt Rubycon.  Here is a sweep showing its impedance and ESR over a frequency range from 100 Hz to 5 MHz:



Notice that when the capacitance is large, the impedance and ESR are the same over a substantial range of frequencies, in this case from about 20 Khz to about 300 KHz.  A simple meter using pulse or square wave techniques will give a good result for ESR over that frequency range even though it is really measuring impedance, because the impedance and ESR are the same over that frequency range..  But with a smaller value capacitor may not be true.  Look at some of the sweeps I show in the linked thread.

[The Electrician]

There are some relatively low cost meters that use sine wave excitation, such as the DE-5000.

I do not use instruments that give the same result of ESR at different frequencies.

I don't understand what you mean by this.

[tigr]

http://www.murata.com/en-eu/products/emiconfun/capacitor/2013/02/14/en-20130214-p1

[tigr]

I don't understand what you mean by this.

I have no desire to detail these things.
Let us continue with the measurement of ESR of small capacitors.
ESR meter 100kHz.
0,1uF/63v.
0,22uF in the circuit.

[tigr]

Capacitor LOW ESR Rubycon MBZ 3300uF/6,3v.By datasheet max.ESR-0,012Ohm.
The ESR meter is with a synchronous detector. Measures a practically pure ESR. The result is in the table.
 My ESR meter shows 0.006 Ohm. Which sensitive detector is needed?

ESR-0,009Ohm.
This practically coincides with the measurement philosophy, which LCR Research showed with its tweezers.

[tigr]

Another complication of the ESR meters is the measurement of ESR of large capacitances.
For example.

[tigr]

  In that case the only way to get a good measurement is to use sine wave excitation.

I once was interested in this issue,but in practice I never saw the difference.

Square wave.
My first tweezers ESR, 100kHz, 5 years ago.
Capacitor Rubycon MBZ 3300uF/6,3v.ESR-0,007Ohm.

[tigr]

Capacitor LOW ESR Rubycon MBZ 3300uF/6,3v.By datasheet max.ESR-0,012Ohm.
The ESR meter is with a synchronous detector. Measures a practically pure ESR. The result is in the table.
 My ESR meter shows 0.006 Ohm. Which sensitive detector is needed?

ESR-0,009Ohm.
This practically coincides with the measurement philosophy, which LCR Research showed with its tweezers.

[The Electrician]

Capacitor LOW ESR Rubycon MBZ 3300uF/6,3v.By datasheet max.ESR-0,012Ohm.
The ESR meter is with a synchronous detector. Measures a practically pure ESR. The result is in the table.
 My ESR meter shows 0.006 Ohm. Which sensitive detector is needed?

ESR-0,009Ohm.
This practically coincides with the measurement philosophy, which LCR Research showed with its tweezers.

What are you trying to show us here?  Please include something more than pictures in your posts; some text explaining the purpose of the post would be good.

[BravoV]

Guess he obsessed with low ESR electrolytic caps, and keep posting meaningless photos of measured used caps.

[tigr]

Please include something more than pictures in your posts; some text explaining the purpose of the post would be good.

And what is there to explain?
It is clear that the russian tweezers, instead of showing the real ESR, shows the maximum permissible ESR-0.012Ohm.

[tigr]

The main feature of this ESR meter is the search for faulty film capacitors of low capacitance in the circuit.

Now,I want to show why the measurement of the tan d(D) is not suitable for this. It is necessary to measure ESR.
Bad film capacitor 1uF/250v.
A good film capacitor 0.47uF/250v.

[The Electrician]

Since D and ESR convey exactly the same information, there should be no reason in theory why one would be better than the other.

The relationship is D = ESR*(2*pi*f*C)

However, as a practical matter, for film capacitors measured at 1 kHz, the measurement of either D or ESR can be difficult because the ESR can be 3 or more orders of magnitude less than the reactance.  This may result in the value of D being given with only a single significant digit.  When converting this low precision value of D to ESR, the resulting ESR will also have only a single digit of significance.  If the numerical result appears to have more digits it should be kept in mind that many of those digits are bogus.

For example, your "bad" capacitor has a measured D of .0002; if we calculate ESR from this we get .1131, but the measured value was .090.  Or, going the other way, if we calculate D from the ESR value of .090, we get .00016 rather than the measured value of .0002

Here's some measured values of a film capacitor with a measurement frequency of 100 kHz.  At this frequency it's possible to get more than a single digit of accuracy.  In this case if we convert the measured value of D (.00996) to ESR we get .0398 which is very close to the measured value of .03984.  Or, if we convert the measured value of ESR (.03984) to D we get .00996 which is exactly the same:



But if we make a measurement of this same capacitor at 1 kHz, the measurement doesn't give as many significant digits for D, and the conversion of D to ESR doesn't give such a good match:



Converting D to ESR, we get 72.10 milliohms compared to the measured value of 73.82 millohms.

Measurements of a good film capacitor at 1 kHz are difficult with even a good bench instrument.  Measurements made with a tweezer instrument are likely to be very near the limit of the tweezer's capability, so we can't really expect highly accurate results.

[3db]

@The Electrician
I don't think it's going to matter,whatever you say to him. 

3DB 

[tigr]

3db
Did you want to say something on the subject?

[3db]

3db
Did you want to say something on the subject?

NO it would be pointless.

 

[tigr]

The Electrician
As always, a very qualitative analysis of the situation.
Thanks.
 Let's try, what will happen at 100kHz.
What I said. Only by measuring ESR, you can see the deterioration of the characteristics of the capacitor. I have been using this factor for 6 years already, to determine the problematic film capacitors in the circuit using a 200kHz ESR meter.
Bad capacitor D/ESR.
Good capacitor D/ESR.

[oldway]

You needlessly use the forum database's storage space by posting unnecessary and repetitive pictures. 
It is like spam and it is against the interests of Dave and of the community.