Electronics > Projects, Designs, and Technical Stuff

ESR meter

(1/9) > >>

tigr:
Hi,
Who made this ESR meter?How can I get a more extended scale near zero?
http://www.nutsvolts.com/magazine/article/january2016_ESRMeterforTestBenchftp://

Paul Price:
ESR is resistance and test and capacitor under test lead length is resistance, so how practical is this? You would have to cancel out the effect of these factors to be much less than one ohm.

In the circuit shown for this ESR meter there is a range switch for selecting 6-ohm FS or 1-ohm FS. You can experiment with using lower valued resistors to get better <1-ohm resolution and re-calibrate the readout with fractional ohm resistors.

If you can easily read the existing <1-ohm scale area of the meter, what's the advantage?

The circuit shown uses a 100KHz sine wave.  The capacitive reactance of a 1uF cap is at this freq. is approx 1.6 ohm. How good is this instrument if the test frequency doesn't already limit CUT capacitors to be >30uF to have any accuracy of ESR <1-ohm?

The website says:
"This meter is not suitable for testing capacitors less than 30 microfarads. If the CUT is too low, the reactance at the measuring frequency becomes significant, resulting in an excessive ESR reading. The solution to this problem is to redesign the system to use a higher frequency. If the need arises, I may try this as a future project."

tigr:
Thanks

--- Quote from: Paul Price on January 02, 2018, 11:05:52 pm ---The circuit shown uses a 100KHz sine wave.  The capacitive reactance of a 1uF cap is at this freq. is approx 1.6 ohm. How good is this instrument if the test frequency doesn't already limit CUT capacitors to be >30uF to have any accuracy of ESR <1-ohm?

--- End quote ---
I want to use this circuit for low-impedance capacitors from 100uF. Therefore, the 1ohm scale is quite suitable. The switch can be removed, this is only additional resistance.

Paul Price:
It doesn't have a 10-ohm FS range setting.

tigr:
1ohm :)

Navigation

[0] Message Index

[#] Next page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod