Relays are probably one of the most reliable and useful pieces of equipment in the market today. They are used in many applications that require some type of switching of a higher current electrical circuit. Simply put, a relay is a remote controlled switch.
Picture your traditional wall switch that controls the light to your bedroom. With the simple flip of the plastic switch, you can turn on and off the power to your bedroom lights. Even though it is a simple flip, you are controlling the flow of electricity to your light bulb.
Depending on how many bulbs you are lighting, you could be sending many amps through your switch.
Your relay operates in a very similar manner. Your relay is a switch that can be commanded to turn on and off. Different relays are rated for a variety of amps, so the styles are based on their intended application. The only difference between a relay and your bedroom switch is that the contacts inside your bedroom switch are moved by the plastic handle you move with your finger. The relay’s contacts are moved by a small electromagnet inside the relay housing.
Each relay has two basic parts, a magnet and a switch. Inside the relay, there is a small metal core with a very fine wire wrapped around this core. When no electricity is applied to the fine wire, the relay contacts remain in their spring loaded position. When electricity flows through the fine wire wrapped around the metal core, an electromagnetic field is created causing the metal core to turn into a magnet. It’s not a very strong magnet and will only attract metal that is very close to it, in this case, the metal contact switch inside the relay housing.
The magnet is strong enough to overpower the spring on the contact switch causing the switch to close. When power is removed from the fine wire, the magnetic field turns off and the metal core becomes just a piece of metal again. The spring pulls the metal contacts apart and the relay turns power off to the device it was operating.
The electromagnet portion of the relay uses a very small amount of amps. Because the magnet and switch never make contact with each other, a low amp switch or circuit can be used to control the relay which can handle a very large amount of amps.
To use the analogy of your finger again, you can use your finger to either turn on your bedroom lights or the gigantic lighting towers you find at a football stadium to illuminate the field. There are huge differences in the amount of power going through the switches, but you’re still using a finger to turn them on and off.
We hope this helps to better understand what relays are and how they work. If you plan on using them in your applications, there is a little more information you will need to know regarding the proper wiring of the relay. This information was left out of this guide to not get too technical and cause confusion. Please contact us and we will be more than happy to explain the next few steps.
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