THE RTD OR RESISTANCE TEMPERATURE DETECTOR ARE TEMPERATURE SENSORS THAT CONTAIN A RESISTOR THAT CHANGES RESISTANCE VALUE AS ITS TEMPERATURE CHANGES. THE MOST POPULAR RTS IS THE PT100 THEY HAVE BEEN USED FOR MANY YEARS TO MEASURE TEMPERATURE IN LABORATORY , TEXTILE , FOOD , CHEMICAL , PHARMA & INDUSTRIAL MACHINERY....... THE PT100 TEMPERATURE SENSORS ARE VERY COMMON SENSORS IN THE PROCESS INDUSTRY. THE PT100 ( RTD ) IS ONE OF THE MOST ACCURATE TEMPERATURE SENSORS NOT ONLY DOES ITS PROVIDE GOOD ACCURACY AND IT ALSO PROVIDES EXCELLENT STABILITY AND REPEATABILITY...PT100 SENSOR ARE MORE ACCURATE , LINEAR AND STABLE THAN THERMOCOUPLE, SHORTLY YOU CAN SAY THAT THERMOCOUPLE ARE SUITABLE FOR HIGH TEMPERATURE APPLICATION AND PT100 ( RTD ) IS SUITABLE FOR BATTER ACCURACY( -50 TO 500 C ) SINCE THE RTD SENSOR'S RESISTANCE CHANGES WHEN TEMPERATURE CHANGES , WHEN MEASURING THE RTD SENSOR YOU A USE A MEASUREMENT DEVICE OR CALIBRATOR THAT AUTOMATICALLY CONVERT THE MEASURED RESISTANCE IN TO A TEMPERATURE READING..... PT100 ARE ALSO RELATIVELY IMMUNE TO ELECTRICAL NOISE AND THEREFORE WELL SUITED FOR TEMPERATURE MEASUREMENT IN INDUSTRIAL ENVIRONMENT , ESPECIALLY AROUND MOTOR , GENERATOR AND OTHER HIGH VOLTAGE EQUIPMENT...