Contact is the current-carrying parts of a reed contact that engage or disengage to close or open electrical circuits. This area is plated or sputtered with Ruthenium, Rhodium, Tungsten or other material.
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An electrical contact is an electrical circuit component found in electrical switches, relays and circuit breakers. Each contact is a piece of electrically conductive metal. When a pair of contacts touch, they can pass an electrical current; when the pair is separated by an insulating gap, then the pair does not pass a current. When the contacts touch, the switch is "closed"; when the contacts are separated, the switch is "open". The gap must be an insulating medium such as air, vacuum, oil, SF6 or other electrically insulating fluid. Contacts may be operated by humans in push-buttons and switches, by mechanical pressure in sensors or machine cams, and electromechanically in relays. Contact materials are usually composed of superior conduction materials such as silver or gold. Cheaper metals may be used to reduce costs for the main contact bump and plated with superior metals.
Even when contacts are separated, there may be a conductive path due to arcing or a glow discharge.