The meaning of RELAY is a supply (as of horses) arranged beforehand for successive relief. How to use relay in a sentence. The relay is the device that open or closes the contacts to cause the operation of the other electric control. The main working principle of the relay is the electromagnetic attraction. A relay is an electrically operated switch that can be used to control an electrical circuit. It typically consists of an electromagnet that, when activated by an electrical current, attracts a movable contact (or contacts) to close an electrical circuit. Relays are used in a wide variety of applications, such as controlling the operation of motors, lighting, and other electrical devices, and can be used to amplify electrical signals or to switch high-voltage or high-current circuits with a ... To summarize, a relay is a simple electromechanical device used to control electrical circuits by opening and closing contacts in response to an external signal.
