Magnetic chip detectors (MCDs) are used to detect metal chips, shavings or particles present in aircraft engine lubrication systems, hydraulic systems and gearboxes. The presence of metal particles may be an indication of wear. MCDs can provide an indication that maintenance is needed or an early warning of impending failure. The MCDs contain magnets incorporated into an electronic circuit. The magnets attract and collect metal particles until the circuit is closed, which results in a remote indication, such as a caution light on an instrument panel, that chips have been detected.