a7n8x-d/thermistor

  • Thread starter Thread starter Nastyd
  • Start date Start date
Hello!

What thermistor should I buy to measure temp of my PSU from psu_temp header?
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Generally, a PSU will come with a thermistor already installed inside
it. You plug the two pin cable directly to the motherboard.

The power supply contains dangerous voltages inside. Line voltage
is rectified and stored on one or two large electrolytic caps,
which if you touch them while they are charged, will throw
you across the room. If you attempt to stick a screwdriver
across the terminals of the caps, to make them safe, the
sound from the arc discharge can deafen you (it is that loud).
A PSU is not a place to play. (Even though it may have safety
discharge resistors on the caps, you can never be sure they
are working, as a discharge resistor is not part of making the
PSU deliver output.) In other words, stay out of there!

If you want a thermistor on a cable, to wave around in the air or
tape to something, then that is OK. The standard for such resistors
is R = 10K ohms at 25C degrees and Beta = 3435. Thermistors have
a curved response, and those two parameters (R_25c, beta) specify
the shape of the curve. While these values are used by many
hardware sensor chips and expected by monitoring programs (because
the monitor program has to know the shape of the curve, to compute
the temperature), the thermistor you want is not that common.
Ones listed in Google have a habit of going obsolete.

Try searching in Google for the two terms "beta 3435", to get
some hints.

An Asus P2T cable may have the same parameters.

Radio Shack 271-110A used to be used for this purpose. AFAIK
it has been discontinued (because Radio Shack really isn't
an electronics supply store any more). I got the last one in
my city, years ago :-) You can also search for that part
number in Google.

If you do manage to find a matching sensor, be careful how you
treat it. For any thermistor, bending the device itself or
even bending the leads near the body of the device, can change
the calibration. (That is only important if you want repeatable
performance - it is probably no better than a couple of percent
accuracy anyway.)

Good luck in your search.
Paul
 
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