Evaluating electronics for differential resistors to be used in sensors

摘要

In these evaluating electronics, having a pulse-width-modulated square wave output voltage, in which a capacitor is alternately charged up to a reference voltage via in each case one of the two part-resistors of the pickup and is subsequently recharged up to a second reference voltage, the measurement value is strictly proportional to the measurement quantity after low-pass filtering. The stability of the capacitor to be charged does not play a role in this case since the same capacitor is charged via the individual part-resistors in each charging cycle so that these evaluating electronics are suitable for high-precision applications. The circuit is furthermore distinguished by a simple construction, low number of parts, small space requirement and low costs.