What Is a Relay Module?

What Is a Relay Module?

A relay module is a pre-assembled circuit board that allows you to control large electrical currents and mains voltages using a microcontroller (like the one on the Bit Board) and some code.relay module They are found in home automation gadgets like curtains, washing machines, and robotics systems. They are also used in industries to control industrial machines and plants, HVAC systems, solar power generation, and security systems.

Relay modules come in many shapes and sizes, with different ratings and functions.relay module Some are designed for specific applications, such as a high-voltage or low-current switch. Others are able to control multiple devices in parallel.

The most important factor to consider when selecting a relay is its switching capability, which can be measured in amperes (A).relay module Generally, the higher the rating, the more current the relay can handle. The switching capacity of the relay is determined by its coil: when current flows through the coil, it creates a magnetic field that attracts a movable armature and opens or closes its contacts. When the coil is de-energized, the armature returns to its original position, which turns off or on the device connected to the NO or NC pins.

In order to operate the relay, an input signal must be applied to the pin connected to it. This signal can be provided by a physical button that is pressed to trigger the module, or a sensor that can detect an environmental condition and send a trigger signal to the relay. The signals are then converted to a digital output by the microcontroller, which sets the relay to an ON or OFF state depending on the state of the input signal.

Depending on the type of relay, there may be other components in the circuit to help protect it from damage. For example, some relays have a diode across the coil that helps keep away the back EMF generated by inductive loads when current supplies through the coil.

Relay add-on boards are available for a wide variety of popular microcontrollers, including the Raspberry Pi, and they can be attached directly to the GPIO ports of the microcontroller or the header pins supported by most SBCs. They are especially useful for projects that require the control of high-voltage or high-current devices.

The add-ons are typically supplied with an independent power source to drive the relay's electromagnet, which is connected through a jumper cap (blue in this case, but yours might be a different color) to the JD-VCC pin on the board. This configuration physically isolates the relay from the microcontroller, allowing you to use it on high-voltage circuits without worrying about safety risks. However, you should still be careful to only connect the relay to a circuit that can safely handle the amount of current it's being asked to switch. Adding too much load to the relay can cause it to fail or even burn out the contacts. This is why it's crucial to choose the right relay for your application, and why you should only use the highest-rated ones.