Electronic Relays: Explained.

 

Electronic Relays:

                Relays are one of the most simplistic components but they are also one of the most important because relays are the link between low-powered digital electronics and high-powered devices. Relays allow digital circuits and digital microcontrollers to switch high-powered devices on and off.

Structure:

A relay basically consists of a coil that builds up a magnetic field. When current is passed through it so what happens is if I run a small amount of power through this magnetic coil which would be inside a relay it actually generates a small magnetic field that will actually magnetically pull a switch into the closed position to allow current to flow from the other side and I'll demonstrate this now what we actually have here are two different circuits and the only thing between them is this relay they're actually both electrically isolated meaning that this side of the circuit is not electrically connected to this side of the circuit so I have a DC power source here which is running at 3 volts and on this side of the circuit I have an AC power supply which could be high power it could be the full AC mains voltage could be 120 or 240 volts and it's connected to this lamp so what happens is by switching on this circuit which could be me switching it on or it could even be a digital microcontroller that switches it on based on a program of instruction that I give it but for the sake of simplicity I'll be turning the switch on the low powered side and just have a look what happens so you can see what's happened here I flip the switch on the low powered side which is a completely separate circuit you can see the electrons do not flow to this side and the switch on this side here was magnetically attracted and towards the coil on the another side because there is now a magnetic force pulling this switch towards this closed position so it's allowed this AC circuit to run this lamp and the lump is  flashing because it is AC and it is running in slow motion in the real life that lamp would be flashing so fast you wouldn't be able to see it so let's just have a closer look at that again focus on this portion of the screen and on the low powered side I'm going to flip the switch and watch what happens the switch was magnetically attracted towards the coil but both of these circuits maintain complete isolation they are two separate circuits now the reason why relays are so significant is because it allows digital devices processes in computers that run at a very low power to control high-powered electronic devices such as motors heavy industrial machinery and many other things basically allowing computers and microcontrollers to interface with these much larger devices and there is an example of this which I will show in the future where I used an Arduino which is a low powered device which runs off of five volts I used an Arduino to run a bit of code that interfaced with Bluetooth from my phone and that meant that I could send a command from my phone to the Arduino which would then activate a relay and then the relay would turn my bedside lamp on and that's what relays are for small projects like that to huge industrial high powered devices, you will find relays in many places they are the main component allowing low powered digital electronic devices to control any other high powered device or appliance