Electrolytic Capacitor Question

mart.s

Member
2008-12-14 1:09 am
Why is it that electrolytic capacitors get heavier (in weight) when they are old, As I understood it -the electrolyte evaporates after time and use, so wouldn't this make them lighter.
Over the past few weeks I have been replacing lots of large old caps in psu's and amps and have discovered the new ones (identical in size, value, voltage, and manufacturer are actually lighter than the old ones by 4-5 grams.

Anyone have any ideas on this?
 

Elvee

Member
2006-09-08 2:04 pm
Why is it that electrolytic capacitors get heavier (in weight) when they are old, As I understood it -the electrolyte evaporates after time and use, so wouldn't this make them lighter.
...

Anyone have any ideas on this?
Nothing to do with evaporation, quite the opposite in fact: older technologies used essentially water based electrolytes, which had a density >1 because of dissolved electrolytes, whereas modern high temp caps use much lighter organic solvents. Which doesn't mean they are better (except for temperature, of course): when you compare 40y old Siemens caps to modern ones, there is little to chose from, except if size and an operating temp of 115°C is of paramount importance, of course...