Alt-BEAM Archive
Message #05189
To: beam@sgiblab.sgi.com
From: "Ben Hitchcock" beh01@uow.edu.au
Date: Fri, 09 Jul 1999 22:32:46 +0000
Subject: [alt-beam] Re: Supercaps (a strange tale)
----------
>From: Steven Bolt
>...I just cracked open the case of a flat (7mm high), large
>diameter (20mm) 1 farad supercap, known to have rather excessive
>internal resistance. What do I find?
>Inside the case is another case, looking much like a button cell
>battery. Cutting away the shrink-foil...
>
>...And out pop two very flat button cells! Each 2mm high, 18mm
>diameter. Both behave like large capacitors. So what I have here
>are two caps of 2 farad each, put in series to jack up the voltage
>rating. The thing was rated at 5.5V, so presumably the coins can
>take 3V each. And the internal resistance is just about low enough
>for a very light photovore using a monostable-based SE. Hmmm.
>
I just pulled apart a panasonic 1F cap, of the same dimensions as yours.
Mine had a plastic shrinkwrap covering. Cutting this off yielded two flat
button-cell like cells. But mine were welded together - so my cap is still
electrically the same is it was before (only minus the plastic shrinkwrap
coating). Maybe those button cells are a standard item? What needs a 2.5V
2F capacitor?
Ben
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