Impedance, LCR, ESR meters

[Jay_Diddy_B]

Hi,
Very interesting results. I love the impedance analyzer  . I can see similar results on my HP 4274A an HP 4275A LCR (Z) meters, but only at 'spot' frequencies and no nice graphs 

There is a reasonably long thread on my ESR adapter here:

https://www.eevblog.com/forum/projects/esr-meter-adapter-design-and-construction/msg372155/#msg372155

This shows the schematic and construction of the unit I supplied to The Electrician.

My design is compromised, it uses square excitation and a phase-sensitive detector. It only uses 3 chips including voltage regulator. It can be constructed on a single-sided circuit board. It is very well protected from applied voltage and charged capacitors.

The combination of square-wave excitation and the phase sensitive detector is relatively good a rejecting capacitive reactance, but not very good at rejecting inductive reactance.

For the service guy, finding bad caps, it works great. For component engineering there are better, and more costly, tools.


Regards,

Jay_Diddy_B

[SgtRock]

Greetings EEVBees:

--I really love the scans of the caps. I am learning a few things. Some of the posts remind me of of studying impedance in my Basic AC Electronics course in the good old USAF. Since the old (Nam Era) days, I have managed, over the years, to teach myself Trig and Calc, and so I can appreciate the Complex Numbers and Vector Analysis approach, which is way less cumbersome than the Algebra only (and just barely Algebra) approach I learned in the service. An excellent series of posts, please keep them coming.

--I want to thank the Electrician again for all the work he has done in getting and posting the analyzer results. He has previously been kind enough to scan some of the caps from my previous projects. I would be glad to send him more from my more recent projects any time. Thanks again to Mr. E. and the other posters.

"Happy for you to desoldering, please."
Wun Hung Lo 1948 -

Best Regards
Clear Ether

[Rufus]

I have found that the DE-5000 in auto mode will indeed show the dominant behavior of a DUT for a given frequency. A capacitor can read as an inductor at certain frequencies yet correctly read as an capacitor at other frequencies.

LCR meters measure the complex impedance between the terminals at a particular frequency. The measurement produces two numbers real and imaginary.

Apart from setting the frequency (and excitation level on fancier meters) none of the controls change how the measurement is made.

Most of the controls determine how those two numbers are displayed, usually as the values in a circuit of ideal components which would produce the same numbers.  Auto mode is just guessing at how you would like those numbers displayed.

[robrenz]

Most of the controls determine how those two numbers are displayed, usually as the values in a circuit of ideal components which would produce the same numbers.  Auto mode is just guessing at how you would like those numbers displayed.

IMO its not guessing, it is displaying inductance or capacitance based on the phase relationship which can change with frequency.  If it displays a inductance value its because the DUT is primarily inductive at the test frequency or displays a capacitance value because the DUT is primarily capacitive at the test frequency. In the same way it will show a resistive value if the DUT is primarily resistive at the test frequency.

EDIT:
You can also force the DE-5000 to read the capacitance on inductance of a resistor by changing the mode. As an example a large wire wound power resistor when switched to inductance will show the inductance and then will also display the resistance as the ESR of the "inductor". The same will work when set to read the capacitance.

[Doug_in_Minnesota]

Electrician:  AWESOME Tutorial. Thank You VERY much. Have you done any other Basics Tutorials on EEV? (I am just getting started here). -Doug   

[BravoV]

The Electrician, thank you for the excellent thread on capacitor, bookmarked.