When building DIY projects, it doesn’t take long before you realise that simple circuits aren’t enough. While they work well for light things like LEDs, you need something that can handle higher capacity when you want to switch larger devices like motors, lights, or pumps.
What a Relay Does in an Electronic Circuit
In simple terms, a relay is an electronically controlled switch. Rather than manually flipping switches with your fingers, a relay does it electronically. This is useful in DIY electronics because microcontrollers and small circuits work at low voltages and, as such, can’t power bigger devices like water pumps, AC lights, or motors. For example, a typical controller might output only 5V with a very small current. While that might be enough to operate sensors, it is insufficient to power larger devices. This has made relays quite popular, and they are used in pretty much all automated systems in industries, buildings, and electronic equipment. When an electronic product receives a signal, it completes or disconnects a high-powered circuit. On one side, it uses low power, but on the other side, the current is high. This makes it possible for sensitive electronics or small ones like IOT to much larger or more powerful devices while still remaining safe.
Popular Relay Types Used in DIY Projects
You’ll find several relays with some minor differences or technologies, but they are mainly grouped based on the principle behind them. And in this case, there are only two major ones.
Electromechanical Relay (EMR): This is the traditional relay design, and it’s based on moving parts. It has a physical coil and an arm that moves when it needs to connect or disconnect a circuit. These relays are more common in DIY projects and even machines, mostly because they are more affordable and easier to understand.
EMRs are mostly used in basic home automation, robotic projects, and security systems. They make it much easier to identify issues within the mechanical parts, so fixing them is also easy.
Solid State Relay (SSR): The difference between SSRs and EMRs is that while the EMR has physical moving parts, the SSR doesn’t. Rather, it uses semiconductors such as thyristors and triacs to switch the load. When the relay receives an input signal, the semiconductor is activated, which then allows a high-voltage signal to pass through.
DIY Projects that Use Relays
There are so many projects that can’t do without the use of relays, including beginner and advanced electronic projects. This is due to the fact that they allow circuits to interact with larger electrical devices without damaging the control board.
For engineers who are developing prototypes, it has become a common trait to combine both the electronic components and the physical design elements, such as 3D modelling for electronics project enclosures. This allows the housing and protection of circuit boards, sensors, and relay models to be done properly. It also ensures accuracy with zero error during installation.
Choosing the Right Relay for a Project
Choosing the right relay for a project is very important as the wrong selection will fail to ensure safe and reliable operations for an electronics project.
Several technical factors should be considered before choosing one.
Voltage Rating
The relay used for this must be able to handle the voltage of the circuit it will control. If the relay’s rating is not up to the level of the voltage, the contacts may fail or become damaged. Think of it the same way a refrigerator stabiliser needs to match the same voltage as the fridge to prevent stress and early breakdown.
Current Capacity
This is basically the maximum electrical current the relay contacts will safely be able to carry. There are high-power loads like motors and heaters that draw a significant amount of current that can be too much for some relays to handle, especially during startup.
Switching Speed
Some applications need relays that can switch quickly. In this respect, while mechanical relays are suitable for many uses, solid-state relays are often better for high-speed switching because they have no moving parts.
Conclusion
In a nutshell, relays are easily some of the most useful components, whether you are working on a professional automation system or a DIY one. By using low-power control circuits to operate high-power devices safely, they make it possible to automate lighting, irrigation systems, motors, and many other applications. Understanding how relays work and choosing the right type for any project can, to a large extent, improve the reliability and the safety of an electronic design.