Comments on: Capacitor testing https://www.epanorama.net/blog/2020/11/15/capacitor-testing/ All about electronics and circuit design Sun, 05 Apr 2026 13:29:12 +0000 hourly 1 http://wordpress.org/?v=3.9.14 By: Tomi Engdahl https://www.epanorama.net/blog/2020/11/15/capacitor-testing/comment-page-1/#comment-1811050 Sat, 19 Aug 2023 05:54:39 +0000 https://www.epanorama.net/blog/?p=187056#comment-1811050 Capacitors that regain charge over time after a short discharge are exhibiting dielectric absorption. Dielectric absorption is charge retained in the dielectric due to finite time required for electric dipoles to completely lose the alignment resulting from charging.

Dielectric absorption is predominantly observed in film caps (small) and electrolytic caps (larger).

Dielectric absorption can cause certain circuits, particularly certain reset circuits, to misbehave.

In rare cases, when the initial stored charge, voltage, or both is large, dielectric absorption can cause dangerous conditions to “mysteriously” re-appear at a capacitors terminals after a period of time. In these cases it is recommended to keep a shorting strap on capacitors after an initial controlled discharge.

Glass dielectric capacitors, like the second anode terminal on a CRT, can be subject to dielectric absorption. This occasionally causes unpleasant surprises during CRT service.

https://en.m.wikipedia.org/wiki/Dielectric_absorption

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