Application based Temperature Sensing and conditioning circuits.

Temperature measurement is one of the basic requirements in Industrial Instrumentation and Data Acquisition. What is being used in industry is one way of looking at things, whereas evolution of new sensors and its interface with microcontrollers is another way. The requirement of the application rules the sensor selection process. From a designer’s point of view you shol


Most commonly used are thermocouples and RTD’s. Next we have semiconductor based analog output sensors and lastly direct digital type ones with microcontroller interface. Other cheap sensing circuits includes diodes and NTC’s.

3-wrire RTD

Thermocouples are good for high temperatures and are active sensors generating millivolts, but they are non-linear and require a cold-junction-compensation circuits. RTD’s on the other hand require current sources for sensing the passive resistance, but are precise and good for low and sub-zero temperatures.

Semiconductor Temperature Sensor

Semiconductor sensors are available as both analog and digital types generating linear analog voltages or interfaced on I2C.

Further are interfacing circuits and working around the non-linearity part in software. I have got great results all these years.

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