Re: gEDA-user: CR2032 with supercap, was Re: [SOT] suggestion for a SMT switch

[Bob Paddock <bob.paddock@xxxxxxxxx>]

> Details are below, but the big question is, can I use a 200 mF supercap
> (EDLC) to dump 100 mA into the motor for short periods ( ~ 1 second)?
> The reason I ask is because the Panasonic datasheet, found at [4], lists
> a "Maximum Operating Current" of 10 uA...  That doesn't make sense to
> me.  Nothing I've researched today on supercaps says I can't do it.

There are two styles of SuperCaps.  Low current ones that are meant
for memory backup,
they have very high impedances, and will not run your motor.

The other style have very low ESR and you could arc weld with them,
for extremely short
times.  These are sometimes called "Boost" caps, and can be quite
large physically.

> Some chaotic googling found this [3], which introduced me to the idea of
> supercapacitors.  Digikey has one [4] that seems to fit the bill.  It's
> datasheet claims a "low ESR" of 200 ohms.  That seems much higher than
> the 1 or 2 ohms I've seen in other places.

Some of the memory caps can be ten times higher than that.
200 does seem high, but not out of line for the small physical cap size.

> Nope, never been to Cleveland.  We Steelers fans break out in a rash if
> we go there.  ;-)

If that means your near Pittsburgh, I'm about 90 miles north of you.
I've always been the classic Nerd.  No interest in sports.

-- 
http://www.wearablesmartsensors.com/
http://www.softwaresafety.net/
http://www.designer-iii.com/
http://www.unusualresearch.com/


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