A relay is a device that allows you to switch power or voltage to different circuits. It is very common to find them in many electrical appliances such as lights, switches and even motors.
The way a relay works is by using a coil that acts as an electromagnet. When current flows through the coil the electromagnet attracts a pole iron in one of the terminals inside the relay. When the electromagnet is removed the pole iron reconnects with a second terminal.
Relays come in a variety of shapes, sizes and voltage ratings. They can also be used to control other devices such as LEDs and buzzers. They can be very useful and are often rated to handle a huge amount of current and voltage.
How to Connect a Relay
There are a few important things that you should know about connecting a relay. The first is how to identify the pinout on a relay so that you can wire it correctly.
For this, you should use a multimeter and a continuity tester that will give you either a NO or NC reading. Once you have these two numbers, you can then start putting the relay in place.
You should then make sure that the coil wires connect to the right pins on the relay socket. This is important because if you don’t, your relay may not work properly.
Once you have the coil wires hooked up correctly, then it’s time to turn on the relay. This will energise the relay coil and cause it to throw its contacts, allowing you to control different circuits.
The coil can be energized with any voltage or current, but most commonly, the relay coil is rated for a specific DC or AC power supply, depending on the relay. This is because the voltage and current needed to energise the relay coil varies depending on the coil’s design.
To energize the coil, you can use a transistor that is driven by another circuit or a relay driver IC. The transistor and IC will both need to be able to amplify the supply voltage and current to drive the relay coil on and off.
In addition to this, you should be able to switch the power to the relay from one of your circuits, which will enable you to control the relay in an automated manner. For this, you will need a microcontroller (such as an Arduino) that can send signals to the relay.
Alternatively, you could also use a switch that allows you to manually turn the relay on or off. However, this is more complicated and requires you to use a microcontroller, which might not be suitable for every project.
If you want to get a feel for how a relay works, then a simple circuit will be enough. The circuit will need a 5V supply, which can be controlled by a transistor and a switch.