This might not be a heat sensor at all. I bought this at a swapmeet and the bag in which this came had the words "Heat Sensor - Hitachi" written on it. The sensor is mounted on an aluminium piece by some form of epoxy. The sensor itself seems to have a white ceramic substrate with zig-zag traces on it.

The resistance of between the leads is around 1K and does not seem to change with temperature when I heated it on an electric stove. Light also does not make a difference(so its not a photocell)

Can somebody please let me know what this is?

edit: I read about PT1000 sensors. It said that they are quite accurate. So I decided to put the sensor in a ice/water bath to get 1000 Ohms at 0 degC. Over time the resistance actually increased and it went over 2000K(multimeter limit). I then decided to heat it a little more than last time over an electric stove. The resistance dropped to about 700 Ohms before the epoxy melted and the sensor came off the aluminium. For a PT100 sensor the resistance should increase with temperature so this behaved opposite.

Another thing I noticed is that the two traces actually do not form a long connecting trace. They are actually intertwined fingers without touching.

enter image description here

  • \$\begingroup\$ Could be a Humidity Sensor? \$\endgroup\$
    – Doc
    Commented Dec 7, 2011 at 22:33

1 Answer 1


It looks like it could be a platinum temperature sensor:

Platinum temp sensor

Here is the Wiki page the above came from. The fact you measure ~1K\$ \Omega \$ sounds like it's a PT1000. Unless it's dead, you should be able to measure some change with a reasonable rise/fall in temperature.

  • \$\begingroup\$ I did some testing and have added the detail above in the original post. \$\endgroup\$
    – Doc
    Commented Nov 3, 2011 at 0:49
  • \$\begingroup\$ It could be a reisitive sensor based on a non-platinum material that has a negative temperature coefficient of resistance. \$\endgroup\$
    – B Pete
    Commented Nov 3, 2011 at 2:09
  • \$\begingroup\$ It's worth noting that the standard abbreviation for this type of temperature sensor is "RTD". \$\endgroup\$ Commented Nov 3, 2011 at 2:53

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