Schematic


PT100 is an RTD sensor, it's resistance changes with temperature. It is 100 Ohms at zero degree celcius. The resistance is measured by connecting PT100 to a Constant Current Source. The voltage drop is proportional to the resistance. It is measured after some amplification, since the voltage is less than200 mV even at 100 degC.



For better accuracy, calibrate CCS value, gain and Offset of A3.