Temp readings and voltage input

[ruijc]

Hi Squibcakes,

Just a question,

Does that thermistor has a linear variation with temperature ?

Where do you get this thermistor ? Any special supplier ?

Thanks

[Squibcakes]

Hi Squibcakes,

Just a question,

Does that thermistor has a linear variation with temperature ?

Suprisingly no it's not that linear. I plugged in the values from the data sheet into excel and created a graph of the curve. It's linear on the higher temps (say 90C +). I wired this up on the bench as per the diagram I posted above and it seems to be working. I've seen mention of the LM35 sensor which is linear and has a higher max temp range which I think would be better but finding it hard to source these...

Where do you get this thermistor ? Any special supplier ?

RS sell them pretty cheaply.
http://australia.rs-online.com/web/s...tsa0wf104fe1b0


Thanks

[ruijc]

The LM35 is very easy to find. Any local store should have it.

The problem with non linear thermistors is the math.
I dont know how to program in a way that the result is always accurate from the "real life".

The LM35 is linear and accurate and is capable of temps up to 150º. You can easly program and get true results.
For applications as the one you want ( model engines ) , you will need a sensor that can go over 135º.

The only problem i see is to get the package of the LM35 fit inside the engine fins.
You could sandpaper off a bit of the package but you will lose accuracy.

.