Design and Performance Studies of Analog Linearizers for Thermistors

The paper proposes simple analog linearization circuits for thermistors. The linearizers are based on a single operational amplifier based circuit, and its basic version operates in a single mode. Multi-mode linearizers, which can give improved linearity with thermistors, are also designed and evaluated. The possible error sources of the proposed linearizers has been identified and analyzed for improved performance. The improvement in nonlinearity of linearizer with respect to K is at the cost of circuit complexity. The efficacy of the presented linearizers are evaluated with the help of simulation and experimental studies. On interfacing with a commercial thermistor, the circuits was shown to render a linearized indication of the input temperature. The maximum nonlinearity for the developed triple-mode linearizer is 1.05% for a wide span of temperature. Feasibility of the schemes for reduced temperature range is also verified. This linearized thermistor system can have a number of applications (e.g., industrial temperature regulation systems).