From: Frank Gruendel (fg2_at_pda-soft.de)
Date: Wed Jan 04 2006 - 15:13:13 PST
> I am unaware of what you speak, so for my sake as well
> as everyone else's could you explain?
> I do not know what a PolySwitch is
In a nutshell, a PolySwitch is a resettable temperature fuse. It "blows"
when the temperature increases above the value defined, and
it resets itself automatically once the temperature is back to
normal conditions. It is a standard protection mechanism
to prevent overcurrent. Most rechargeable cells will become
very hot when more current is drawn that what they deem appropriate.
The PolySwitch breaks the circuit before conditions are likely
to become dangerous and re-establishes the connection automatically
when the temperature is OK again.
The pack will work fine if the PolySwitch is replaced with a
piece of metal the way it is in your pack, but you gave up
this important precaution. If ever a component on the mainboard that's
(electrically) close to the battery is shorted out, and if it can
withstand high current for some time, the cells are likely to
turn the eMate into a blob of melted plastic. If you are lucky.
They might decide to explode before this happens, if you are
not lucky.
Be aware that no company will put hardware in a pack that isn't
absolutely necessary. Not even Apple :-)
Frank
-- Newton software and hardware at http://www.pda-soft.de
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