backup battery for BS2 ?

Archiver

Does anyone know of a backup battery for the BS2 so it will come on
when the power goes off? kind of a rechargerable one? not too
expensive? Any ideas? I need to keep the stamp on at all times.
thanks all...

Archiver

basilflorida wrote:
> Does anyone know of a backup battery for the BS2 so it will come on
> when the power goes off? kind of a rechargerable one? not too
> expensive? Any ideas?

A "diode-OR" backup battery is cheap & easy. A resistor
in parallel with the battery isolation diode allows the
battery to charge from primary power. See Horowitz & Hill
for more info on this,

http://www.maxim-ic.com/appnotes.cfm/appnote_number/170/ln/en
is a backup power management IC.

regards, Jack