Electrolytic capacitors: how to test them with a DC Voltage source (leak current, read textbox)

Too HIGH is too LOW….....(!) IMPORTANT FLAW: I constantly say in this video that the DC resistance of the electrolytic capacitor (in a certain situation) is too HIGH, but I mean: too LOW. I say that on the following moments in the video:
0.21 and 9.02 and 10.10 and 12.13 and 13.37. Sorry for that!

I leave it this way because for the “good understander” this is issue is clear: Too low DC resistance (leak) = problems, especially on higher voltages.

The video shows how you can easily check electrolytic capacitors with a DC Ohms meter that has the following settings: x10 and x 100 and x 1K and x 10K. All electrolytic capacitors show a “leak current” in the Ohms measurement.

That does not have to be a big problem, as long as the voltages to which they are soldered are low (of course: shortcut = defective!).

On higher voltages this could be a serious problem, especially when the DC resistance (causing the leak current) proves to be persistive during the normal working voltage and during normal use of the device: organ, radio, tv, computer, in switch mode power supplies, etc.

Reason: on the normal DC working voltage and normal use of the device we can be sure that there is enough and proper DC to keep the plates in the electrolytic properly “formatted” and (thus) there is no defective in “electrolytic” terms.

Reasons for a too high leak current is more or less always: aging or a too high working voltage (take, to be safe in hobby circuits, always a 20%-50 % higher working voltage for an electrolytic capacitor).

The normal leak resistance for HV electrolytics: in the mega-ohm range. Normal leak resistance for low Voltage electrolytics: 300-500 K or higher. Worst case scenario: a complete shortcut of an electrolytic, measured in both directions, with the probes of the Ohms meter (on x1 and x 10) reversed and not reversed during a few times.

Shortcut of an electrolytic wil surely cause imortant failures to other electronic components: FET’s, transistors, resistors can burn out in that situation. You can use Ohms law (U=IxR) to calculate the effect of parallel resistance to an electrolytic capacitor.

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Regarding all my video’s: I constantly keep them actual, so the original video’s with the most recent information are always on YouTube. That is the source, and search there. When my video’s are reproduced or re-edited on other websites/channels you can not (!) be sure about the original content (=really working electronics) and important adaptations to the circuits.

Be aware of that, I saw on the internet my circuits reproduced in a poor or even not proper way. I can not help that, sorry. Upload 10 january 2019.

Sources: Handboek der Radiotechniek, Deel 3, N.V. Uitgeversmaatschappij E. Kluwer Deventer/Jakarta, maart 1951, Rens & Rens, page 295 and 296 (ir. TH.J. Weijers, Ir. J.M. van Hofweegen, both from Philips, Eindhoven)
and: Radio Laboratory Handbook By M.G. Scroggie B.Sc., A.M.I.E.E., consulting Radio Engineer, ILIFFE & Sons, Ltd, London, (1940's?) and "Retro Radio", Issued by Elektor International Media, december 2008, Author Ko Tilman, ISBN 978-90-5381-234-1.