Abstract: A self timing test circuit switch powered by the same conductor as used to carry data may be used in vehicles where it is desirable to test and confirm the continuity of a critical circuit by illuminating for a brief period of time an indicator lamp after power-up of the vehicle. The switch may be used in sensor circuits where the sensor is a normally open switch and the normally open configuration can not otherwise be distinguished from an open circuit due to a wiring fault or a burned out bulb. Typical applications include checking the continuity of leads leading to metallic chip sensors in the engine and drive train oil or hydraulic fluid of aircraft engines.

Abstract: A self timing test circuit switch powered by the same conductor as used to carry data may be used in vehicles where it is desirable to test and confirm the continuity of a critical circuit by illuminating for a brief period of time an indicator lamp after power-up of the vehicle. The switch may be used in sensor circuits where the sensor is a normally open switch and the normally open configuration can not otherwise be distinguished from an open circuit due to a wiring fault or a burned out bulb. Typical applications include checking the continuity of leads leading to metallic chip sensors in the engine and drive train oil or hydraulic fluid of aircraft engines.

Abstract: The presence of particulate debris flowing in a hydraulic fluid flow system includes a source of infra-red light passing through a window of the fluid flow line while fluid is flowing therethrough. A portion of the light is directed to a monitoring photodiode prior to reaching the fluid flow line. A detector photodiode is positioned to receive light passing through the flow line, the hydraulic fluid flowing therethrough and out of a second window. A trap is positioned between the hydraulic fluid flow line and the detector photodiode to prevent the direct rays of light from reaching the detector photodiode while permitting scattered light to reach the detector photodiode. A reduction in the amount of light reaching the detector photodiode results in an alarm being activated.

Abstract: Apparatus for monitoring particles in fluid systems in which a detector has electrical contacts that are bridged by particles captured from suspension in the fluid. Upon detection of a particle, a control microprocessor stores a predetermined quantity of electrical energy on a capacitor, which is then discharged through an inductor to burn off the particle at the detector. The burn-off charge and return lines from the charge storage capacitor are un-grounded, and are connected by respective electronic switches through relay contacts to the conductors connected to the chip detector. The relay contacts are also connected to the inputs of a differential amplifier for detecting presence of a chip bridging the detector contacts and monitoring continuity of the conductors to and from the detector. The relay is powered by system voltage, and in the event of system power failure connects the chip detectors directly to warning lamps on an operator panel.

Abstract: A spring contact switch for a printed circuit board includes a flexible spring contact member affixed to a circuit board at one end and operatively available at an opposite end and an electrical component affixed to the circuit board with a lead member forward for contact by said flexible spring contact member.