Dennis Plunkett wrote:

> Yes, but requires 2 components and one of them must be very type
> specific i.e. N channel 3V FET.  This makes this option not cheep in
> the production format.

  Ha Ha!  Tough luck.  You want the function, you buy the part!  But
what is the other component to which you refer?

> One diode is cheeper and just as effective,

  Anyone have a measured comparison on this?  Schottky versus 3V FET at
various currents including 2ľA, 100ľA, 1mA, 10mA?

> the mechanical means that have been brought up will only sort of work,
> as you can almost put money on it that there will be someone that
> manages to get the small cells in backwards.  The mechanical means is
> just another level of protection.

  Absolutely!  Thus the products with the lithium cell(s) permanently
soldered in.  You all know the "invent a better idiot" story.
-- 
  Cheers,
        Paul B.