Electrical charge sensors measure electrical charge in electrical components such as electrical relays and electrical sensors. An electrical relay is an electrical component that completes or interrupts a circuit by physically moving electrical contacts. An electrical sensor consists of two main elements: a detector and a platform that communicates with the detector through an active interface. Electrical charge sensors are just one type of electrical sensor. Other electrical sensor types include charged coupled device (CCD) or CCD image sensors, electrical field strength sensors, and electrical capacitance sensors