How Realy works - Simple explanation

How Realy works - Simple explanation 

Basic definition :


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.

A relay is an electromechanical switch. It works in the same way as a manual switch, but instead of having to manually push the switch, you apply power to it to change the switch position.

This was the first component I learned about and it helped me to start understanding how to electronics works.

A relay consists of

• an electromagnet
• a mechanical switch

Electromagnet

An electromagnet is a simple device made up of a wire wound in a coil around a core of ferromagnetic material such as iron.This is a very interesting device and it is easy to build one yourself.

To create your own electromagnet all you need is a nail and some insulated wire. Wind the wire into a coil around the nail and apply power. Beware, it can get very hot if you have too few windings or too much voltage!

How it works

When a wire conducts current, it produces a magnetic field. If we wind a wire into a coil around a core of ferromagnetic material such as iron, we magnify this field and we get an electromagnet with enough magnetism to do some interesting stuff.

Mechanical switch

The relay also consists of a mechanical switch. It may look like this:

By User:Bisgaard, language neutral version by Teslaton (Modification of Image:Relæ3.jpg) [GFDL or CC-BY-SA-3.0], via Wikimedia Commons

When the electromagnet (1) is powered, it will break the initial connection between the middle (3) and the left (2) pin and create a new connection between the middle (3) and the right (4) pin.

On many relays there are at least two switches inside so that you can switch two devices at once.