Thanks - was Re: Cool calculator

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Fri Apr 4 18:39:20 2003

> This reminds me that just the other day I saw a calculator in a
> thrift, IIRC, that carried the message to remove the batteries
> if you were going to run it on the wallwart for more than four
> hours to avoid over heating the alkaline cells. Sounds like a
> similar problem?

I have a couple of 4-function Commodore calculators that have a warning
on the back to 'unsnap and remove the battery if using the PSU' (or words
to that effect).

Decimo VATman calculators (a popular 1970s model in the UK, so called
because it had a % key, and was useful for working out VAT (sales tax))
have a 3 position power switch. Off, On, and Charge. There's a warning
not to use the Charge position unless you fit NiCds...

Casio got it right (for once). Their machines took a special NiCd battery
pack consisting of 2 AA cells in a plastic holder. When it was inserted,
a peg on the plastic holder closed a switch in the battery compartment,
enabling the charger circuitry. Of course hackers (like me), soldered a
jumper across the switch and put normal AA NiCd cells in (a pair of those
was a lot chaaper then the battery pack), but we can't blame the
manufacturer for that.

HP and TI often designed machines to run off the (special) rechargeable
NiCd pack only.

-tony
Received on Fri Apr 04 2003 - 18:39:20 BST