[Test-Equipment] ESR meter

[Mike Sloane]

I have an RCA 153 Test Oscillator that dates to the late 1930's, and one 
of the electrolytic capacitors has the words "dry" on the paper wrapper. 
<http://public.fotki.com/mikesloane/old-electronics-and/rcaoscillator1532.html> 
(it is the big one on the right in the image) I always wondered what 
that meant, and now I know.

Mike

On 7/4/2011 4:37 PM, Richard Knoppow wrote:
>
> ----- Original Message -----
> From: "Ken Kaplan"<krkaplan at cox.net>
>>
>       This has piqued my curiousity, I realize I am not sure
> when electrolytic capacitors were invented or came on the
> market. Worth some research. I know the earliest ones used a
> liquid electrolyte and in later ones it was formed into a
> paste. The latter were called "dry" but of course weren't
> really. This is reminescent of batteries where the first
> ones used a liquid electrolyte (as is still done in auto
> batteries) but soon "dry" batteries using a paste were
> invented. Again, I am not at all sure of the date. I have no
> idea if the two technologies are related.
>
>
> --
> Richard Knoppow