On Fri, 26 Aug 2005 11:47:55 +0100, Timothy Murphy
wrote:

I do find chargers have a kind of "black box" behaviour -
it rarely seems to be explained what they are doing,
or when they will stop charging.

A concept known as "user transparency". You nees not know anything about
electrons or holes to use a semiconductor device any more than how
telephone exchanges and mobile cells work to make a 'phone call. I was
going to have a look in my charger, but it has screws needing a bifurcated
screwdriver to remove them. Maybe when the workshop is open, I'll cobble
one together.

John Schmitt