This article shows how to make Relay Module that can be used for Arduino and other applications such as circuit boards and other DIY projects. With this tutorial you will be able to make a relay module yourself.

So what is relay? A relay is an electrically operated switch. It consists of a set of input terminals for a single or multiple control signals, and a set of operating contact terminals. The switch may have any number of contacts in multiple contact forms, such as make contacts, break contacts, or combinations thereof.

What is relay module?
A relay module is a set of components that is electrically operated and works based on a signal. That can be connected to an Arduino or a transistor and or any other application that the output is a signal or a voltage. Same as relay the relay module is used to control high voltage electronic devices. A Relay module is a mechanical switch which is electrically operated by an electromagnet. When the electromagnet is activated with a low voltage, that can be 5 v, 12 v, 32 v, … it will triggers a mechanical arm that pulls a contact to make a connection between two contacts. Relay modules are used for high voltage controls, and big loads. Relay modules has low power lose in a circuit. In other hands they are slow and they are not quick as transistors.

Modes of connections:
Normally open state (NO)Normally closed state (NC)CommonNormally open (NO) In the normally open state, connections are open and do not allow current to pass through. And the initial output of the relay is low. In this state, the common and the normally open pins not connected unless relay is switched on. Normally closed state (NC) In the normally closed state, the connection are normally closed and both are connected to common pin and the initial output of the relay will is high when it is not powered. In this state, the common and the normally close pins are used.