How a Relay Works
A relay is an electromechanical switch. It works in the same way as a manual switch. It is very useful not only for turning the power of a device on and off automatically but also for switching higher power devices with a low power.
An electromagnet is a simple device made up of a wire wound in a coil around a core of ferromagnetic material. To create your own electromagnet, a nail and some insulated wires are enough. Wind the wire into a coil around the nail and apply power. Attention, it can be very hot if you have too few windings or too much voltage!
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.
Notes of caution: Always check the voltage and current rating of the relay switch. Some are designed for switching low voltages only, while others are meant for switching higher voltages.
For more information, please contact a representative at EPCB.