Capacitor Leakage, and ESR Explained

[ppppenguin]

Mike, all electrolytics leak to some extent, it's part of how they work. Too much leakage is obviously harmful. I've seen tables and/or rules of thumb for how much leakage is tolerable for a particular size and rating of capacitor but can't find them when I want them.

Likewise all capacitors have ESR. It's a question of how much is tolerable for your application.

For most vintage applications, neither leakage nor ESR is usually too critical. For a switchmode PSU, ESR matters a lot.

PS: This data sheet has some leakage numbers: https://www.mouser.com/datasheet/2/88/WBR-32673.pdf