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How do you make a thermistor linear?
There are two basic ways to linearize a thermistor in hardware: voltage mode and resistance mode. For example, placing the thermistor in a voltage divider is considered as voltage-mode linearization because the divider output voltage is directly used.
Does a thermistor need voltage?
The controller will only accept a certain range of voltage. For example, if a controller range is 0 to 5 V, the thermistor voltage needs to be no lower than 0.25 V so that low end electrical noise does not interfere with the reading, and not higher than 5 V in order to be read.
How do you set up a thermistor?
Connect one end of the 10K resistor to 5V, connect the other end of the 10K 1% resistor to one pin of the thermistor and the other pin of the thermistor to ground. Then connect Analog 0 pin to the ‘center’ of the two.
What kind of sensor tolerates variations in Vref?
Some sensors are ratio-metric and thus tolerate variations in VREF. Bridges, such as strain gauges, are one such sensor. Thermisters, as part of voltage-divider across VDD to GND, is another.
What is the VRef of ADC in a microcontroller?
You need to provide an ADC reference voltage, to pin 33 (assuming LQFP-100). That is Varef. Page 38 of datasheet shows a VREF pin. Tie that to VDD. Your reported voltage will only be as accurate as the VDD. Also, connect 0.1uF across VREF to GND, to provide the charge needed during the conversion.
How to calculate RT for AVR-NTC thermistor circuit?
I ran your code in Python and got 285 for adc_val = 1 and -84 for adc_val = 1023. With an adc_val of 318, I get 25.9. RT at that point is 4504. So it looks like your equations should be right.
How to get RT, the value of resistance of NTC?
Someone can explain me how i get RT, the value of resistance of NTC from ADC value? thanks. How I have to set up the ADC in AVR? with internal voltage reference or not? do i have wrong formula? I need to read “exact” temperature in range of -10°C to +30°C more or less.