HYBRID THICK-FILM MAGNETORESISTIVE SENSORS

This paper describes a first prototype of a thick-film sensor using Ni-based pastes, whose resistance changes with the applied magnetic field. The magnetoresistive properties of thick films (Ital. Patent No. 9477/A86 (1986)) have been exploited for the development of hybrid sensors for proximity detection and rotational speed. The conditioning electronic circuits are specifically designed to compensate the relevant temperature effects, which otherwise would overwhelm the weak magnetoresistive effects. The electronic solution, though simple, proves to be very effective. On this basis integrated magnetoresistive sensors, with standard trimmable hybrid circuits and Ni-based films on the same substrate, have been developed in the framework of a collaboration aimed at looking for reliable integrated sensors for various applications. The design and operation of a prototype are described. Some areas of application of hybrid magnetoresistive sensors will be analysed.