Connecting a Relay Module to a Microcontroller

Today we are driving high current high voltage applications using only a microcontroller and relay. To accomplish this, we are going to take a closer look at a few different types of relay modules you might find across the Internet. We will first go over the components and connections available on each module, then we will go over the schematic to get a better understanding of how each module works, and finally we will demonstrate how to connect these modules into our circuits. Throughout this video I will touch on important considerations to mindful of to ensure you don’t damage your microcontroller or worse the item connected to the relay.

00:00 Intro
00:39 Hardware Overview
02:56 Relay One Schematic
06:22 Relay Two Schematic
07:53 Relay Three Schematic
08:20 Demo with External Power Supply
09:52 Demo without External Power Supply
11:19 Recap

Hardware:

Helpful Links:

[kitkirkyen]

This is the best explanation of relays that I have ever encountered for so long. Thank you so much sir for this.

[johnathanelkins]

Thank you for this video! Every other video I've found has only explained how to plug in a couple wires. You actually explained how things work and why they're set up in a certain way, which is exactly what I needed. Thank you!

[adrianrawlings]

Best explanation I've found for the relay module. You covered the technical stuff in depth without over-complicating it.
You covered the traps well, which was what I was wanting to know. I've worked with relays in industrial applications, so I had my suspicions about the jumper. Thank you for confirming the internal circuitry on this.

[ramgo]

Finally, the mystery between the relay modules are resolved for me, Thanks!!!!

[Manu__R]

I've been trying to find a good explanation of how to wire these relays, the 3 pins on the load side confused me, but you cleared it up really nicely. Thanks!

[Joemama-kmnp]

Refreshing to see a clear video on the subject. One thing to note and I wished more presenters did was talk to their audience like we are just home DIY's not knowing schematics and just visually seeing how to wire everything together. I've never used a breadboard so wouldn't even know where to plug something into it. We just want the pertinent info and move onto another subject.

[omehoque]

This is a high-quality educational video. It is unique in the sense that it describes the physics inside the relays. In addition, it shows three different ways of connecting the relay module at 3:31, 5:10 and 5:52. Thank you very much for the video.

[markharrisllb]

I don’t care what your subject is all the best teachers have passion for their subject. We saw that in spades here along with very clear explanations.

[ocdtechtalk]

Excellent video. Rare to see an explanation of the circuit with cause and effect.

[randyhill]

Great video Brad. Thanks. I was really struggling trying to understand how the jumper in the Relay Module Two unit actually worked. I didn't realize that the optocoupler input was bi-directional. I know this video is a few years old and that most of those watching aren't going to build their own circuits from this tutorial, but I think there is an issue with the circuit diagram for the Relay Module Two. I'm pretty sure that you need a resistor between DC+ and the optocoupler or the optocoupler will sink as much current as DC+ will give it, causing it to burn out. I know there is one in the actual unit.

[flickmew]

you are my lifesaver for understanding relay module, I was about to make the diagram in everycircuit and when I try to run it, the page says I gotta pay, so I was lil bit frustated, then I finally watch this video, thanks sir

[Ron-pebp]

Very good treatment of hard-to-find info!
On "Relay Module One" and connecting a/the GPIO Pin to VCC so you can have the relay turn on when the GPIO pin is HI. (starting at around 5:30):
Nice for modules with only one relay. But my multi-relay modules only have one VCC pin.

[SkydivingKiwi]

Top quality. Clear and concise. Thanks for the video!

[wackojacko]

This was a really clear video, well-explained. In particular, I was interested in understanding what JD-Vcc was doing and why the jumper is there/not there. Thank you.

[shigarfmashaam]

Brad, I really want to see more videos like this. If it is luck or what, I was trying to figure out a way to operate my relay with active high signal and I found this video right here. You have been a huge help. Subscribed.

[remist]

i tought theres nothing to learn about driving relays .. but i was wrong so much informational video!! thanks :)

[UselessDuckCompany]

I have been looking for exactly this! Thanks for making this.

[AshokaRajalingam]

Brad, Thanks. So helpful. You saved my board.

[wonderwang]

After I destroy 2 esp32 boards, luckily I found this to let me not third boards. It may draw to much current by coil to wreck them before I test any project.

[lelilimon]

Amazing explanation, after viewing, rushed to watch for more of the similar explanations and... daamn