With many electrical systems requiring higher power than what a microcontroller can provide, the relay module finds use in a lot of different applications. So, what exactly is this useful little device and how does it work? In this article, you will learn the following about the relay module:
- Relay module meaning
- Relay module function
- Relay module working
- Relay module uses and price
What is a Relay Module?
Relay modules are simply circuit boards that house one or more relays. They come in a variety of shapes and sizes, but are most commonly rectangular with 2, 4, or 8 relays mounted on them, sometimes even up to a 16 relays.
Relay modules contain other components than the relay unit. These include indicator LEDs, protection diodes, transistors, resistors, and other parts. But what is the module relay, which makes the bulk of the device? You may ask. Here are facts to note about it:
- A relay is an electrical switch that can be used to control devices and systems that use higher voltages. In the case of module relay, the mechanism is typically an electromagnet.
- The relay module input voltage is usually DC. However, the electrical load that a relay will control can be either AC or DC, but essentially within the limit levels that the relay is designed for.
- A relay module is available in an array of input voltage ratings: It can be a 3.2V or 5V relay module for low power switching, or it can be a 12 or 24V relay module for heavy-duty systems.
- The relay module information is normally printed on the surface of the device for ready reference. This includes the input voltage rating, switch voltage, and current limit.
Relay Module Function
What does a relay module do? The relay module function is mainly to switch electrical devices and systems on or off. It also serves to isolate the control circuit from the device or system being controlled.
This is important because it allows you the use a microcontroller or other low-power device to control devices with much higher voltages and currents.
Another relay module purpose is to amplify the control signal so that it can switch the higher currents using only a small out of power from a microcontroller.
Relay Module vs. Relay
It is also important to note the difference between a relay vs. relay module. A relay is a single device that has an electromagnet and a switch, or it can be the solid-state type.
A relay module, on the other hand, is a board that has one or multiple relays on it and several other components to provide isolation and protection.
Because of its modular construction, this type of switching and control device can be many different configurations. It can be a single-channel relay module for a single load or it can be a multi-channel device with multiple relays to control several circuits.
Relay Module Working
How does a relay module work? The relay module working principle is actually quite simple. It uses an electromagnet to open and close a set of electrical contacts. Here is the sequential working of relay module devices for easier understanding:
- The typical relay module connection points include an input side that consists of 3 or 4 jumper pins, and an output side that has 3 screw terminals.
- When the control signal is applied to the input side of the relay, it activates the electromagnet, which attracts an armature.
- This in turn closes the switch contacts on the output (high voltage) side, allowing electricity to flow and power the device or system that is connected to it.
- To prevent flyback voltage from damaging the relay module circuit and the input device, a diode is often placed in parallel with the electromagnet coil. This diode is known as a flyback diode. It allows current to flow in only one direction.
- When a higher level of isolation is required, an optocoupler is used. An opto-isolated relay module has the photoelectric device on the input side, which is used to control the electromagnet’s switching action.
Relay modules are available with either normally open (NO) or normally closed (NC) switch configurations.
- A NO switch is open when the electromagnet is not activated, and closed when it is activated.
- An NC relay switch, on the other hand, remains closed by default, and only opens when the relay is activated.
Relay Module Uses
Relay modules are used in all sorts of applications, from controlling lights and motors to more complex systems such as automation processes and safety or security systems. Here are just a few examples of the relay module uses in different applications.
Home Automation Relay Module
Relay modules are also used in home automation systems to control lights, appliances, and other devices. The home automation relay module is often used with mains electricity. So it’s mostly rated for 10A or less for maximum current, and up to 250V AC.
Industrial Relay Module
In industrial applications, the industrial relay module is used to control machinery, process controls, and other industrial equipment. Other relay module uses in industrial settings include lighting control and the control of alarm or security systems.
Automotive Relay Module
Relay modules are widely used in automotive applications. The automotive relay module controls things like headlights, turn signals, and even the starter motor. A car relay module is also found in many other automotive circuits such as those that operate remote starters or theft alarms.
Arduino Relay Module
Hobbyists often use a relay module with Arduino in their projects. An Arduino is a microcontroller board that is widely popular in DIY electronics projects. The relay module, when paired with an Arduino, can control various appliances and devices.
