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Topic: Thermistor question (Read 407 times) previous topic - next topic

dtokez

I have just started messing with a 10k thermistor and got a temperature to display on my lcd using the first simple example on this page http://www.arduino.cc/playground/ComponentLib/Thermistor2

is this anymore or less accurate from using the longer examples and/or a look up table?

also, what are the pro's (if any) and cons of not using a voltage divider and just running 5v through the 10k thermistor and measuring what comes out the other side?

how long could the cable to the thermistor be without effecting the resistance too much?

thanks!

retrolefty

Quote
also, what are the pro's (if any) and cons of not using a voltage divider and just running 5v through the 10k thermistor and measuring what comes out the other side?


Well if you mean the 'other side' then wires to a Arduino analog input pin, that won't work. +5vdc is all that will appear at the 'other end' at all times regardless of temperature change. You must use the thermistor in a circuit where it's resistance change Vs temp will cause a current change in a circuit, A voltage divider circuit does that.

Lefty



dtokez

I see, so really all that would vary would be the current? but still 5v as you say

retrolefty


I see, so really all that would vary would be the current? but still 5v as you say


Nothing would vary, because a arduino analog input pin has many megohms of input resistance, so all the analog input pin would see is a +5vdc voltage, no change of current, no change of voltage, just a constant +5vdc.

Lefty

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