Is ESR measuring with DER EE DE-5000 precise?

[Chupacabras]

I have LCR meter DER EE DE-5000, but I am not sure about precision of ESR measuring.
I measured several different types of capacitors, with all available frequencies, and measurements at 100Hz are very suspicious.
Are they OK, or the results are not really trustworthy?

Here are some mesurements:

10uF 16V 20% ceramic SMD 0805
7.50ohm @100Hz
0.44ohm @1kHz
0.02ohm @10kHz
0.02ohm @100kHz

10uF ceramic SMD 0805 another brand
8.30ohm @100Hz
0.63ohm @1kHz
0.04ohm @10kHz
0.04ohm @100kHz

10uF 16V tantalum SMD 3216
2.30ohm @100Hz
1.00ohm @1kHz
0.87ohm @10kHz
0.67ohm @100kHz

1uF 100V, 85C, electrolytic, RM2.5
23.70ohm @100Hz
7.13ohm @1kHz
3.71ohm @10kHz
2.95ohm @100kHz

10uF 100V, 85C, electrolytic
3.00ohm @100Hz
0.99ohm @1kHz
0.58ohm @10kHz
0.51ohm @100kHz

33uF 16V, 105C, electrolytic
4.40ohm @100Hz
1.95ohm @1kHz
1.43ohm @10kHz
1.13ohm @100kHz

680uF 25V, 105C, electrolytic
0.10ohm @100Hz
0.07ohm @1kHz

[elecman14]

If you want a quick sanity check grab a low value resistor maybe 1 ohm and put it in series with the cap you are measuring. If the measurement value goes up by the resistor value that is a good sign. 

[Fgrir]

If you look at the datasheet they specify the ESR reading accuracy as a percentage of the total UUT impedance.  For your 10uF @100Hz case that is 159ohm, and for your 1uF case it is 1.59K.  So you would expect the ESR readings of small capacitors to get really bad at low frequency, but having said that your measurements look worse than the spec would call for.  Have you run the CAL on the meter before taking those measurements?

EDIT: Just tried it on mine with a 10uF 16V 0805 X7R cap and it really just is that bad at low frequency (I used 120Hz and measured 6.84 ohm).  Running CAL didn't make any significant difference to my measurement either.

[Chupacabras]

Yes, I have executed CAL.

[DaJMasta]

While some of those readings seem a bit high, I don't think they're necessarily out of line.


I don't have the same caps to test as you do, but I checked a couple and saw roughly similar readings (same instrument) - used a 25V 33uF Chinese cheapy that I've had for years and the 100Hz ESR was actually higher (4.8 ohms) whereas the higher frequencies were a bit under.


I think as a sanity check, adding a resistor in series is a good idea to check the meter's ESR readings in particular, and maybe checking the same cap with the cap measurement on a different device (like a DMM) could make sure that the reading for the capacitance is in line.

If you've got a function generator and a DMM, you could actually do some math and plot out a curve for one of these caps to see if it lines up with the readings you're seeing.  Would be time consuming, but doing that on one part could give you an idea of whether the meter is about right or not.

[Fgrir]

While some of those readings seem a bit high, I don't think they're necessarily out of line.

I agree that the readings aren't insanely bad, but I'd expect the ESR for the ceramics at least to be inversely proportional to frequency in the 100Hz to 100KHz range.

[Chupacabras]

If you want a quick sanity check grab a low value resistor maybe 1 ohm and put it in series with the cap you are measuring. If the measurement value goes up by the resistor value that is a good sign.

I have just tried that. Measured value went up by 1 ohm.
But I have no idea what does it mean in respect to precision of meter measurements.

[DaJMasta]

If you put a 1 ohm resistor in series, you increase the equivalent series resistance by one ohm across the range of frequencies.  If it goes up by that much, then you know that the measurement/calculation portion is at least still measuring and scaling properly - still could be off calibration somehow, but if, for example, you saw an increase of something other than one ohm or different amounts on each frequency, you would know that something about the way the unit was measuring was faulty.

Less a calibration check, more a verification that something hasn't gone horribly wrong.  Unless you have a higher spec instrument that's in good working order or reference caps with a stated, stable ESR, then it's going to be very difficult to measure if the readings are correct.  Like I had mentioned, though, a good DMM (or a scope) and a signal gen can give you a measurement that you can calculate ESR from directly.  Maybe not to the same spec as your DE-5000, depends on the other equipment, but at least as a good external comparison.

[Chupacabras]

Well, I measured it today more carefully at all frequencies.
These are my measurements:
resistor alone = 1.002

	100Hz	1kHz	10kHz	100kHz
1uF 100V, ER85, electrolytic =	23.2	7.61	4.31	3.54
+ resistor in series =	24.3	8.63	5.32	4.54
difference =	1.10	1.02	1.01	1.00

So it seems that difference is almost exactly 1 .
I was holding legs of resistor and capacitor in my fingers, that could result in some error.

[gege1244]

Hello
I made a mistake
The DE-5000 that I own measures too low the resistances of 10 ohms
I wanted to set VR2 which did not change anything, but when you change it, the value of the point TP1 changes
I got 1,300 Volts by positioning VR2 as originally (more or less)
Can give me the value you find on your devices
Thank you
A user who likes this product

[radhaz]

Mine reads 1.3170vdc. Measured with Hioki DT 4281.

[gege1244]

OK
Thank you for this information.
I will be able to set VR2 to this value.
If one of you knows what this setting is, it would be good for everyone.
I think my DE-5000 will find a good accuracy
Thanks again to everyone