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Originally Posted by leejsmith
The 100k Pot works perfect thanks 
I dont have any 40k resistors how would i use the pot ?
at the moment i put the 100k thermistor on the center of the pot and then to the 3118. all i get is a wave and the amplitude increases when i touch the thermistor.
I am going to look though this thread again i am sure i saw something like this in there.
(edit) i put the thermistor across the pot 5v and the output and it works ok.
I tried running the power of the pc psu and a switch mode psu but they are both the same. |
Is it a 10K or 100K pot? If it is a 10k you need to get a larger value resistor because no matter how you do it it will be very non linear in the temperature range you are working with.
Wired the way you have it your range is limited, you are not using the full resolution that you can achieve. If its a 100k pot wire it as attached, set it at half way and do not touch it. Then you can start thinking about calibrating.
You will find that you can change the value by adjusting the pot, it might feel like a way to calibrate it but it is not, it is just going to destroy the linearity of your readings.