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sensitivity of thermistor

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elec123

New Member
hi,

could someone tell me a typical sensitivity of a thermistor used in a potential divider circuit for temps ranging from 0-100 degrees.

Also how can this sensitivity be increased?

cheers
 

John Sorensen

New Member
Define "sensitivity." Do you mean "accuracy" or "repeatability"? "Lag"?

The main cause of error with thermistors, IMO, would be that the R vs T curve is non-linear, so most of the error would be calculating the temperature for a given R.

As I've heard it said, most temperature measurement devices are not super-accurate as it is usually not necessary to get super-accurate temperature measurements.

You could increase your performance by making sure the thermistor leads are short, use precision resistors in your voltage divider, make sure your A to D is ratiometric, maybe use a low pass filter.

j.
 

Russlk

New Member
The thermistor is a non-linear, negative temperature coefficient resistance. If you look up the data sheet for a typical thermister, the resistance change with temperature is high at low temperatures ( and consequently less accurate). The thermistor value is given at 25 deg C and is usually in the middle of the curve where the rate of change of resistance with temperature is moderate. It is common practice to put a linear resistor in parallel with the thermistor to linearize it.
 
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