Re: general cap questions and BIG Farad caps

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Crow Leader by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla-at-lists.symmetric-dot-net>

> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<dhmccauley-at-spacecatlighting-dot-com>

[cut cut]

> > You will rarely come across a 1 Farad capacitor. more usual values are
in
> uF
> > nF or pF.
> >
>
>
> Actually, 0.5-1 Farad caps are much more common than one would think.
They
> are used all the time in a variety of
> applications although almost 99.99% of the time, they are low voltage <20
> Volts
> 5V, 1 Farad caps are about half the size of a 35mm film case.

Hmm, Below is a link to pics of some 1 Farad capacitors. These ones pictures
are called "double layer" caps. All three are about 10 years old, the blue
ones were actually made by Standard Oil. The larger one has a lower ESR so
they can charge and discharge much faster then the higher resistance smaller
ones. The green cap can run a small motor. There is a newer style of these
capacitors that come in welded steel cans with that come in values of
hundreds of Farads at something like 2 volts. These somehow have an even
loser internal resistance where you can draw many amps from them to the
point they are dangerous, like a large lead acid battery.  Shorting out the
older caps like pictured does nothing interesting at all. They are made of
activated charcoal as electrodes and some sort of fluid as the electrolyte.
The premise is activated charcoal has a huge surface area and a capacitor
with huge plates has a high capacitance.

KEN