Abstract: Means for checking the voltage level of a battery used in an apparatus including an operational amplifier powered from the battery and an indicating means operatively connected to the output of the operational amplifier. The indicating means provides a replace battery indication which is presented when the battery is in a replacement condition and the amplifier is operated at saturation.

Abstract: A liquid level sensing electrode structure provided by flat cable which has a plurality of insulated conductors cut to various lengths with end portions exposed to provide sensing electrodes is used in a liquid level sensing system. A common electrode is provided for the system. A separate voltage inverter is provided for each sensing electrode and connects with a voltage source to provide a microprocessor compatible signal when liquid is presented to the common electrode and the sensor for the inverter. A liquid utilization apparatus having a liquid sensing system provides a flow of liquid along the electrode structure to prevent sediment buildup.