Electromagnetic relays are switching devices that utilize induction to perform a specific task within an electrical circuit or system. The electromagnetic phenomenon is used to create a magnetic field, which is then focused and used to open or close circuits and even perform mechanical functions.
An electromagnetic relay uses the principle of induction to control electronic circuits and devices. A coil of wire sets up a magnet field that is concentrated around a core. This magnetic field is used to physically open and close circuits or activate armatures for mechanical work. One of the key advantages of electromagnetic relays is that they are electrically and physically separate from the circuits they control. Another distinct advantage of relays is their ability to switch circuits. This ability eventually has given rise to more powerful and faster electronics, including the modern computer and microprocessor.
The switching capabilities of the relay are what eventually led to the modern information age. The simple on or off status of the most basic relay has been at the core of communications since the advent of the telegraph and is now responsible for the speed and accuracy of modern electronic devices. Relays are one of the fundamental parts of nearly all electronic components and are found in sizes ranging from microscopic to those capable of moving heavy machine parts.