NTC thermistor sensors

Thread Starter

MattBuzzBurbank

Joined Nov 14, 2019
7
Hi, I am a technician who frequently has to replace NTC sensors on the thermoblock boilers of coffee machines that get as hot as 300 degrees F. Quite a frequent repair! Instead of getting these sensors in Germany used, I want to order them direct from Mouser or Digikey and there are several mfg like VISHAY and AMETHERM who put out the lug sensor I need. Ok, they are 10K ohm sensors but there is a variety of course specified by parameters I do not understand. Can somebody give me a recommendation here? Main thing is they need to withstand the temperature mentioned and be responsive as possible to changes in temperature. OR can I take my existing NTC sensor and have somebody extrapolate these params? Best way to go here!
 

Alec_t

Joined Sep 17, 2013
11,981
Providing the 10k thermistor is rated > 150°C by some margin (you would have to check its datasheet) and can be mounted as you want it, the other parameters (e.g.β) may or may not be critical, depending on whether it's used simply to set a temperature limit or to enable the display of actual temperature.
 

Thread Starter

MattBuzzBurbank

Joined Nov 14, 2019
7
Ok, it's being monitored by a control board to set a temperature limit for a thermoblock boiler, no display needed, can somebody point me to a 10K NTC lug thermistor made by VISHAY or AMETHERM that would work best?
 

Alec_t

Joined Sep 17, 2013
11,981
Yes I have a good thermal sensor I can measure resistance for it in boiling water - now what?
That would enable you to decide which β value the thermistor has. The β parameter is a measure of the rate of change of resistance with temperature and is one of the parameters listed on datasheets.
Here are some reasonably priced possible candidates operable up to 300°C listed on the Digikey site, but you would have to fashion a DIY lug mount.
 

MrChips

Joined Oct 2, 2009
23,070
Take a good thermistor and measure the resistance at three temperatures, 0°C (stirred ice and water), room temperature (25°C) and boiling water (100°C) all measured with a reliable thermometer.

From there we can figure out the parameters.
 
Top