How Does a Electronic Relay Work?

Introduction

Whenever you use any electrical equipment in your home or at work, an electric relay is responsible for allowing it to work. An electrical relay exists for one sole purpose: To allow the electricity needed to flow to a certain point that will then allow the equipment to work properly.

Parts of an Electronic Relay

There are four basic parts of an electronic relay. The first is the armature, which moves up and down. When it is up, the pathway is open and no electrical current can move forwards; when it is down, the pathway is closed and therefore allows the electrical current to move smoothly through to the next point.
The second part is called the electromagnet. Like a magnet, it pulls the armature to it when it senses even small amounts of electricity. This allows the armature to close and therefore the electrical current to move through it.
The third part of an electronic relay is the spring. This keeps the armature open to keep electricity from touching the electromagnet.
The fourth part are the electrical contacts. While there may be several located along a path where an electrical current moves, at the point where the relay is located there are two. These ensure that the current can continue to move along the intended path.

Electrical Current

The electrical current comes to the electrical contact on one side of the armature, then travels up the armature. At this point the armature is open, or up, and there is no connection yet.

Attraction to the Magnet

At this point the electromagnet senses and begins to pull the electrical current towards it. This process allows the armature to be pulled down by the attraction the current has to the magnet. The spring is pushed down in the process, allowing the armature to close and initiate the contact.

Making Contact

At this point, for the electrical current to continue, electricity finds the electrical contact and is allowed to continue on its path towards its destination.

Back to the Beginning

Once the electrical current is shut off, the magnet no longer has anything to attract the armature down to it. This results in the spring pushing the armature back up and the path is once again open.