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Author Topic: NTC Thermistor vs LM35  (Read 3166 times)
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Wanted to ask some opinions on the pro's and cons of each

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Thermistors are very cheap, in the ballpark of $0.20. They're not very precise and their resistance change with temperature is non-linear, so you have to do a little "work" in your software to figure out the temperature.

Active devices like the LM35 are more expensive (>$1) but are more precise and provide a linear voltage-vs-temperature characteristic making it easier to figure out the temperature.

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The LM35 is calibrated.  The thermistor has to be calibrated against some known-good temperature standards.
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if you want the temperature in Celcius and i have the LM35, just use this code:

Code:
tempC = analogRead(tempPin);
  tempC = (5.0 * tempC * 100.0)/1024.0;

and u'r pretty much all set,  with the NTC/PTC u'll need to make a circuit and even then you wont be able to do anything nearly as simple as this code.
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cheers for the code

is there any other alternative other than a thermocouple that can read a higher temperature
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you want to read above 155C ? 

you could try this:
http://www.omega.com/rtd.html

but i dont know anything about it. i can just see the ratings.  if you need more advanced help on temperature i can refer you to the sensor forum in arduino: http://arduino.cc/forum/index.php/board,10.0.html 
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ty

looks like a good alternative
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