A relay is an electrically operated switch. It consists of a set of input terminals for a single or multiple control signals, and a set of operating contact terminals. The switch may have any number of contacts in multiple contact forms, such as make contacts, break contacts, or combinations thereof.
source/image(PrtSc): The Engineering Mindset
Relay works on the principle of electromagnetic induction.When the electromagnet is applied with some current it induces a magnetic field around it.A simple electromagnetic relay consists of a coil of wire wrapped around a soft iron core (a solenoid), an iron yoke which provides a low reluctance path for magnetic flux, a movable iron armature, and one or more sets of contacts.
When an electric current is passed through the coil it generates a magnetic field that activates the armature, and the consequent movement of the movable contact(s) either makes or breaks (depending upon construction) a connection with a fixed contact. If the set of contacts was closed when the relay was de-energized, then the movement opens the contacts and breaks the connection, and vice versa if the contacts were open.
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How relays work. In this video we look at how relays work, what are relays used for, different types of relay, double pole, single pole, phototransistor, solid state relay, semiconductor, flywheel diodes, Suppressor diodes, DPDT, Double Pole, Double Throw Relay, Double throw relay, single throw relay, latching relay, nc, normally closed relay, no, normally open relay, Electromagnetic, electromechanical relay.//The Engineering Mindset
