On 30 Aug 97 at 18:30, William Chops Westfield wrote:

>     >Is the Timex Indiglo an EL display?  If so, how do they power
>     the >inverter off those small lithium cells?  It's the only
>     digital watch >lighting system I have any time for <g>
>
>         I've always wondered, I don't think so, try putting a strong
>         magnet
>     close to it while it is on, it seems to dim, and if you leave it
>     there too long the Indiglo stops working!!
>
> I'm pretty sure it's EL.  Go to the SIPEX web page (www.sipex.com)
> and you'll find a bunch of info on their EL inverter chips, designed
> to work on as little as 1.1V or 3mA...  I assume a magnet would
> interfere with the coil used to produce the high voltage (ie by
> saturating the core.)
>

You mean it permanently biases the ferrite?  (to stop it working
permanently)  Another scenario might be that the fet gets blown when
the magnetic properties are changed.
MikeS
<mikesmith_oz@relaymail.net>