Abstract: Improved switching circuitry for use in connecting a remote control signal circuit to an electrically powered circuit wherein power for the remote control signal circuit is provided by the electrically powered circuit. Power metal-oxide-semiconductor field-effect transistors (MOS-FETs) are connected to a control signal output of the control signal circuit and provide the function of at least one diode of a full-wave rectifier bridge in the switching circuitry. The MOS-FETs respond to a logic 1 control signal to establish a low impedance path across the output of the full-wave rectifier that is connected to the electrically powered circuit.

Abstract: Liquid level sensing circuitry useable for detecting the presence of an acceptable or unacceptable level for a liquid, such as engine oil. Prior to termination of the operation of the engine, the circuitry presents an unacceptable level indication at a control point. After completion of a time delay following termination of engine operation, an acceptable level must be presented for a time to cause an acceptable level indication at the control point which is maintained pending initiation of engine operation. Upon initiation of engine operation a first discernible indication is provided for a time period if the control point presents an unacceptable level indication with a second discernible indication provided for such time period if the control point presents an acceptable level indication.