Temperature was one of the first physical parameters to be measured in the process field and has been sensed in just about every way imaginable over the years. NTC thermistor elements, either alone or as part of temperature sensing assembly, are being utilized more and more where the need to sense or control temperature is needed.
Temperature measurement is the most common application for NTC thermistors. The high sensitivity of thermistors and the ability to manufacture components with tightly controlled temperature accuracy has made the NTC themistor an ideal device for low cost temperature measurement.
As the cost of digital electronics has dropped while the degree of miniaturization has increased, the ability of the design engineer to utilize a high precision low cost thermistor has increased. Todays’s microcontrollers allow a number of thermistor sensors to be interfaced to a control system allowing several locations within a building or piece of equipment to be monitored simultaneously. An example of such a system is shown below. Additional zones can be monitored and controlled with the only additional cost being that of the thermistor assembly. The microcontroller will determine the temperature of thermistor bu converting the analog input, either voltage or current, to a temperature value.