A linear resistance-to-frequency converter

A resistance-to-frequency converter consisting of a Wheatstone bridge followed by an integrator and a comparator is described. It is basically a relaxation oscillator whose frequency changes linearly with a resistance change detected by the bridge. Analyses show that a resolution higher than 0.05% is possible with the simple configuration and an excellent linearity is kept over the wide resistance change by a simple compensation method. The converter is therefore best suited for an interface of a resistive sensor. Experimental results are also given to demonstrate its performance