Re: Electrolytic capacitors

SNIP

>If you have any stocks of large, expensive electorlytic caps, then I suggest >you gently charge them to full voltage from time to time. Put a resistor >in series so that they don't overheat if they are already a bit leaky. >Remember to discharge them (through a resistor please!) so that when you go >to put them into your circuit or back in your parts box, you don't blow up >any other components. >

So I should individually form each of those hundreds of electro's I have had in stock for 20 years or so? Shouldn't take too long to do,should it?

I agree that it is a good idea that any electro which you are planning to use and which has been stored for at least 5 years, should be first tested, but you don't go around re-forming all capacitors in storage as a matter of course.

RE-FORMING capacitors which have been in storage is only necessary prior to use. Some manufacturers spec sheets recommend reforming is not necessary unless they have been in storage for "a minimum 3 years" but that is overkill and just playing safe on their part. I have tested caps (Matsushita's are excellent) which have not seen a jot of DC for more than 20 years and both their ESR and capacitance measured nearly as as good as when brand new.