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ADC - Thermistor interfacing

Posted: Fri Jul 28, 2017 10:43 am
by Deepak
Hie ,

I want to interface thermistor to ADC of ESP32. I am using voltage divider circuit to give input to ADC channel 4. I have attached same circuit below. Rt is my thermistor and Rs is my series resistor(3.3K). For testing purpose I am using resistor of 27K instead of thermistor.
I have configured my ADC for 12 bit resolution and have set attenuation to 11 dB which means its full scale voltage is dependent on VDDA or 3.9V. I am facing problem in calculating and interpreting ADC output. Can anyone tell me how to interpret ADC output in terms of voltage. Also when I find resistance Rt value from the ADC output I get other value which it should be 27K.

Please help me with this.

Thank You.
adc.jpg
ADC interfacing circuit
adc.jpg (1.29 MiB) Viewed 3583 times
Regards
Deepak