Applications of Thermoresistive Sensors Using the Electric Equivalence Principle

In this paper, a survey on the characteristics of thermoresistive sensors [positive temperature coefficient (PTC) and negative temperature coefficient (NTC)] and their applications to measurement structures that use the electric equivalence principle, in special radiometers and anemometers, is presented. The dynamic responses of the architectures and the influence of the operational amplifier offset voltage on the instrument performance are discussed. Alternative architectures employing pulsewidth modulation (PWM) and sigma-delta analog-to-digital (A/D) converters are also shown.