A relay switch is an electrically operated switch that uses electromagnetism to convert small electrical stimuli into larger currents. It consists of a set of input terminals for a single or multiple control signals, and a set of operating contact terminals. Relays are used where it is necessary to control a circuit by an independent low-power signal, or where several circuits must be controlled by one signal. They can be used in a wide range of applications such as home automation, cars and bikes (automobiles), industrial applications, DIY Projects, test and measurement equipment, and many more.
Relays can switch one or more circuits, and each switch in a relay is referred to as a pole. The number of circuits a relay connects is indicated by throws. Depending on the number of contacts and number of circuits it switches, relays can be classified. There are several types of relays, including:
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Electromechanical Relays: These are the most common type of relays. They use an electromagnet to mechanically operate the switch contacts.
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Solid State Relays: These use semiconductor devices to switch the circuit. They have no moving parts and are faster and more reliable than electromechanical relays.
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Reed Relays: These use a small coil to control a set of contacts that are sealed inside a glass tube. They are very reliable and have a long life.
Relays can reduce the need for high-amperage wiring and switches, which are expensive and take up space. Therefore, switching to relays in electronic systems can be cost-effective and space-saving. Relays are normally used in control panels, manufacturing, and building automation to control the power along with switching the smaller current values in a control circuit.
