Controlling tiny LEDs with an Arduino can be a fun project to kick off your journey learning DIY electronics. But do you know what’s even more fun? Powering light bulbs with a custom-built Arduino project: large, high-power, room-enlightening light bulbs!
However, the Arduino can’t emit more than 5V from any of its pins, let alone enough to power a light bulb that needs 30 to 40 times the voltage for an LED. That’s why you’re supposed to use a relay module instead. Here’s how to do that with your Arduino.
What Is a Relay Module?
Relays have two kinds of terminals: one that’s high-voltage tolerant (think 220V) and another that only accepts low-voltage output.
When you pass an electric current through the low-voltage pins, you’re powering an electromagnet that pulls a “switch,” turning it either on or off, depending on the configuration you’re using.
An SPDT relay always has six pins: typically with three male headers for connection to the Arduino and three screw terminal pins to connect to mains electricity.