Help identifying sensor in ceramic heater.

Question

Im trying to read and calculate temperature from a soldering iron heater sensor like this. http://www.ebay.com/itm/150856111427?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

I dont believe it uses a thermocouple as I cannot read any voltage across the sensor wires with multimeter. Resistance does increase as temperature increases, telling me it's some type of thermistor. Does anyone have any info on the type of sensor used in this application and how to read and calculate with arduino. Another option would be to get heaters in the same approximate size and shape with known sensors. I've been googling for days and cannot find any clear information. Any information would be greatly appreciated. Thanks

shabaz · Answer

Hi Erik,

It's usually an RTD (which changes resistance with temp) or a thermocouple (which generates a tiny voltage) for these Hakko cartridges (I read about it a while back, when I was looking to purchase a soldering iron). It needs additional circuitry, but you should be able to find details if you google something like 'rtd adc' or 'thermocouple adc'.

Heaters should be easy to find, and shouldn't cost that much, see a manufacturer like this one, they seem to have lots of distributors listed. They normally don't have an in-built sensor, so you can place the sensor exactly at the point where you wish you measure the temperature.