Witch one of these diy esr meters is more accurate ? - Page 1
Forum section: electronics / testgear

author: pedroteck
author_rank: Contributor
timestamp: January 12, 2015, 10:24:59 pm
content: Hello everybody here .I am currently thinking of building a esr meter for troubleshooting some old equipment i have mainly for checking capacitors .I have found on the net some attractive projects , but am really confused witch one to choose for good testing accuracy .Here is some schemes :

author: pedroteck
author_rank: Contributor
timestamp: January 12, 2015, 11:16:50 pm
content: Is anyone familiar with these designs ?

author: PedroDaGr8
author_rank: Super Contributor
timestamp: January 13, 2015, 12:09:06 am
content: ESR is over rated for capacitor testing. tan delta (aka tan D or just D) is much better and its even listed in the capacitor datasheet.

author: pedroteck
author_rank: Contributor
timestamp: January 13, 2015, 12:12:04 am
content: Quote from: PedroDaGr8 on January 13, 2015, 12:09:06 amHi .I have a LCR meter with the D measurement on it , if its better then i wont waste my time on building one .How can i convert D to esr ?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 13, 2015, 12:25:11 am
content: The second and third are better than the others...Even so, all of them scream "well, WWWHHHHYYYY???" at various points, for both electrical and typographical reasons. None of them provide a self-calibrated, instrumental sort of measurement of ESR, so NONE of them are "accurate" in an instrumentation sense. Probably, all four will still do the job anyway, as long as you don't care about actual values or understanding what ESR should or should not be..Tim

author: pedroteck
author_rank: Contributor
timestamp: January 13, 2015, 03:01:39 am
content: Ok then i will use the D measurement instead .

author: Bryan
author_rank: Frequent Contributor
timestamp: January 13, 2015, 05:47:27 am
content: There is also this one. Had built before and seems to work ok.http://members.shaw.ca/swstuff/esrmeter.html

author: pedroteck
author_rank: Contributor
timestamp: January 13, 2015, 02:14:45 pm
content: Quote from: Bryan on January 13, 2015, 05:47:27 amYes easy design but hard to find a galva like that .

author: codeboy2k
author_rank: Super Contributor
timestamp: January 13, 2015, 06:03:44 pm
content: Quote from: pedroteck on January 13, 2015, 02:14:45 pmDon't be fooled by the look. It's just a 50uA meter. They can be found everywhere.adafruittmarteBayYou need to print your own faceplate. The meter software below can help but its about $35.http://www.tonnesoftware.com/meter2.htmlYou don't need that software, as you can just as easily do a one-off run in MS Paint, or Photoshop, or GNU Gimp, or Google Sketchup..By the way, also from that same site, tonnesoftware.com, is the Elsie program, which is a pretty decent LC filter designer. They have a free limited edition personal use version.http://www.tonnesoftware.com/

author: PaulAm
author_rank: Frequent Contributor
timestamp: January 13, 2015, 09:48:04 pm
content: I built one very similar. Really, for what you're using these things for, it doesn't make any difference if it says .20 ohms or .25, or even .35. Absolute accuracy is not essential for this.It will not identify a shorted cap, but it's a good tool to easily identify most failed caps in circuit.If I actually wanted to characterize a cap, I'd use a real LCR meter.

author: wraper
author_rank: Unknown
timestamp: January 13, 2015, 10:38:23 pm
content: Quote from: PedroDaGr8 on January 13, 2015, 12:09:06 amESR is listed where it really matters -> for all low ESR types exact for each capacitor variant. Dissipation Factor on the other hand usually is rated as separate value for each voltage rating. But not for each possible variation within series.

author: pedroteck
author_rank: Contributor
timestamp: January 13, 2015, 10:45:30 pm
content: Quote from: PaulAm on January 13, 2015, 09:48:04 pmI have an LCR meter that identifies the dissipation factor (D) and also if the capacitor has a series or parallel configuration .Now how do i know the dissipation of a good or bad cap ? is there a chart or a mathematical way to convert D to ESR ?

author: wraper
author_rank: Unknown
timestamp: January 13, 2015, 10:54:29 pm
content: Quote from: pedroteck on January 13, 2015, 10:45:30 pmThey are essentially the same thinghttp://www.illinoiscapacitor.com/pdf/Papers/impendance_dissipation_factor_ESR.pdfTo calculate between them you need to know capacitance and measurement frequency.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: January 13, 2015, 11:01:54 pm
content: Quote from: wraper on January 13, 2015, 10:38:23 pmActually, DF is usually listed for both each voltage and each range of 1000uF

author: Pjotr
author_rank: Frequent Contributor
timestamp: January 14, 2015, 03:09:40 pm
content: Did you consider using your PC soundcard?http://www.sillanumsoft.org/ZRLC.htmhttp://www.artalabs.hr/(look at "LIMP")There are more, Google for soundcard lcr meter

author: dannyf
author_rank: Super Contributor
timestamp: March 05, 2015, 02:06:40 am
content: The first and the last one should be very good, with linear readings as well, due to their use of syn detectors.You shouldn't look to ESR meters as a "measurement" tool - they are actually more of an indication.For a simple but accurate ESR meter, check out one of my designs, utilizing one opamp + a few capacitors + resistors + diodes.

author: Adal
author_rank: Contributor
timestamp: March 06, 2015, 06:17:08 pm
content: I use this "ESR METER":http://members.shaw.ca/swstuff/esrmeter.htmlLook at:http://www.xe1bps.blogspot.mx/2010/04/medidor-esr-capacitor-electrolitico-esr.htmlBest regards

author: oldway
author_rank: Super Contributor
timestamp: March 07, 2015, 07:47:42 am
content: None of these schematics is good because they do not accept significant DC voltage at the input.It is essential to measure the ESR even of charged capacitors without destroying the device.You will also discover that an ESR meter has another extremely useful application: check all kind of battery types.The health condition of a battery, regardless of the type and capacity, can easily be evaluated by measuring its internal resistance.Diagnosis by comparison with a new battery is almost infallible.I use more often my ESR meter for this application than to check the capacitors.My ESR meter is the ESR3 schematic from Jay_Diddy_B topic"ESR Meter Adapter Design and Construction"with 10 and 100Khz test frequencies.For reading, I use a five bucks DT830 digital multimeter.This ESR meter is fully protected up to 400Vdc input voltage.It is also linear and very easy to use.Only short circuit the probes, adjust offset to 0V reading with the potentiometer and then, use it.The reading in volts must be x10 to have the resistance value in ohms.