Yes, this IS Newton related, because the outcome of this discussion will
control whether I need to update my refurbishing instructions or not :-)
> I am not really happy with the terminology for "thermistor" what is in
> my opinion most likely a thermo-fuse and for "resistor" which should read
> thermistor. Of course every resistor will change its resistance with
> temperature, but while this is a side effect for resistors that may cause
> trouble in your circuit, this effect is especially distinctive and
intended
> for thermistors, because they are used for sensing temperature.
I'm inclined to agree. When I encountered this "thing" (which I so far have
called a thermistor), I found a pdf datasheet where (I think) it was
called a thermistor. I will look if I can dig it out.
Is a fuse in the English language an element that can only cut a connection
(because the wire in it has melted), or would a component that cuts and
re-establishes a connection be called a fuse, too? Personally, I would
probably call a component like that a switch.
> 2) Regarding the thermo-fuse: I saw a Newton bursted at the seams due to
> overheating and blowing up of the battery pack during charging with a
wrong
> (too powerful) power supply. Thus the thermo-fuse seems not to contribute
> very much to safety
Well, for a start, only MP2k and eMate packs have this component, all
earlier
models don't. Was it a 2x0 you saw bursted?
> and in my opinion you can leave it out with no doubt as
> long as you use the original power supply or a power supply with less then
> 9W power.
If that was true, Apple wouldn't have put it in in the first place.
You can leave the brakes out of a car for an amazingly long time without
dying. A friend of mine does this on a regular basis, when he comes to me
for his brakes to be fixed, the deceleration provided by what is left of
them is next to nil. Still, personally I prefer my car's brakes to be
fully functional whenever I am in the car while it is moving.
And I would buy a car with a spare set of brakes that automatically helps
out if the main set has a problem immediately.
> The object you are referring to is not a thermistor, it is a fuse -
> plain and simple!!!
If a fuse is a component that can only cut a connection for good, it
isn't.
> However if you use a thermal fuse, remember that you have to use a
> good heat shunt on the leads when you solder it or else the heat from
> the soldering iron will blow it. (in commercial production they spot
> weld them as this produces far less heat).
This is what makes me think it is not a fuse, but a switch. It is
spot-welded to the cells originally, but I always
solder these things back on, and they have always survived just fine.
Frank
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