Novel Liquid-Level Sensor

Normally, the level of a liquid in a container is determined by sensing changes in the capacitance or resistance between a pair of electrodes that are immersed in the liquid. Generally speaking, this technique requires fairly complicated circuitry to protect the electrodes against electrolysis (and associated corrosion). In addition, in many cases the liquid must be conductive for the measurement principle to actually be usable. The circuit presented here shows that an alternative approach is possible.