"Wiebe Cazemier" wrote in message
...
On Tuesday 11 April 2006 23:13, I.F. wrote:
The NTC thermistors I've salvaged from a whole range of scrap PC monitors
have ranged from a few hundred Ohms to as high as 12k at room
temperature,
the running resistance is usually 5 Ohms or less.

These were also inrush limiters? Monitors also use these things in their
degausing system, if I'm not mistaken. I can imagine their values needing
to
be a lot higher, to allow the alternating current to diminish to zero.
Yet,
you'd think they'd use PTC resitors for that (to let the current start
high,
end low when the resistor is hot), so perhaps I'm wrong here

But that is quite a difference. Mine don't differ at all when in use or
not.

The 9-10 Ohms explains why there is "5.0" written on both of the NTC's BTW
.
I wonder if they mean that's their room temperature resistance, or
running-hot
resistance.

There are 2 common types of degauss thermistor, the most common of these has
2 PTC elements one of which is in series with the degauss coil the other is
connected across the mains input - this is constantly heated to ensure that
the degauss PTC proper is heated above its cut off temperature. This ensures
there is no magnetic ripple on the picture in normal operation.

The less common type contains both NTC & PTC elements, the current drawn by
the equipment flows through the NTC to keep the PTC element warm during
normal operation.