Connecting a Relay Module to a Microcontroller

[@kitkirkyen2002]

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

[@johnathanelkins4285]

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!

[@adrianrawlings2470]

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.

[@ramgo0]

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

[@hensonbl]

Awesome, thank you.

[@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!

[@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.

[@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.

[@flickmew99]

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

[@randyhill8472]

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.

[@SkydivingKiwi]

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

[@ocdtechtalk]

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

[@Joemama-km9np]

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.

[@lelilimon]

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

[@Ron-pe4bp]

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.

[@remist]

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

[@hensonbl]

Glad it helped!

[@AshokaRajalingam]

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

[@UselessDuckCompany]

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

[@wackojacko1997]

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.

[@raymondtang539]

Thanks for your video. Excellent explanation.

[@alexmcewen9594]

Very well explained. Thank you for posting this video.

[@sennabullet]

Very nice explanation. Thank you for sharing your knowledge !

[@alazyfrog5969]

Excellent video, and you solved my issue at 5:45, thanks a lot.

[@lastdraco1]

Adding this to my tool box!

[@michaelcostello6991]

Super video. Great clarity

[@matze2022]

Excellent video, thank you!

[@benjaminmelgar9327]

Great demonstration and so helpful thank the video.

[@arya8431]

thank you, great explanation of various module type and it circuit schematic

[@sarathisankar227]

It works when I did with external supply , helps a Lot

[@muhammadazamazam2931]

Bundle oF Thank,s For your supper good Explane every point from A to z Thanks Alot.

[@BuildswithBrian]

Thank you Brad, that was a very well explained demonstration

[@lesp315]

Thank you for the video. You nailed all of it.

[@tommytan8571]

this this most beautiful video. thanks for your parents for making you

[@XepRuduk]

At 7:29 it seems like the microcontroller is seperated from the relay? Can't you just have an external power supply going to the DC+ and DC- on high level trigger?

[@1986ah]

Very good explanation

[@axok]

this video is insane, thank you

[@merseytrainz]

Thank you for your video. Its very informative and interesting.

[@hensonbl]

Thank you.

[@anandjoshi8554]

@@hensonbl so if i am not using jumper to avoid any feedback> can i use same 12 v dc power supply source to give 12 v to jd vcc and same 12 v to vcc pin ...in DC plc output side ?

[@nguyenvantaihust]

It's very useful. Thank for your video

[@omkarkhade4602]

Great tutorial, thanks a bunch.

[@joshuaoduroadu5376]

Excellent video. Thanks for sharing and do make more videos like this.

[@hensonbl]

Thanks, will do!

[@halfaperson-co8jh]

helped a lot with my project thanks

[@barneycarparts]

Great vid Thanks for sharing you said: I created all of the wiring schematics in the video using Adobe After Affects.

[@saleemkhan-mx9jw]

Thanks for knowgable video sharing.

[@wonderwang1585]

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.

[@nevermind-wp3bf]

😂

[@praveenraj387]

Awesome explanation 😍😍😍👌👍

[@OnosTech]

Very explanatory. Many thanks.

[@odonusa007]

Dude, I was totally confused about these relay modules. I wish I had seen this before I bought some. Anyway, thank you. [Click -> Subscribed 😀]

[@sosscs]

at 4:22 , I don't understand why the protection diode have the small yellow animated dots going through it. Shouldn't the diode be reversed?

[@santiagocorrea783]

Great video, I definitely subscribed to watch more like this. It was a really good explanation.

[@hensonbl]

Thanks for the sub!

[@k4qdex]

quality tutorial, nice.

[@hensonbl]

Thanks!

[@popojunior4206]

Just came back to give you a like and subscribe. Great content.

[@kedarpuranik750]

Thank you for the video.

[@pableitor]

Great video but I think theres a bug in the relay 2 schematic at 6:22 . The optocoupler transistor output cannot be connected to Vcc, otherwise it is shorting the Vcc to GND when the opto is active , isn't it ?

[@haywardhaunter2620]

Nice catch. I'm guessing the board has a third resistor to limit the current through that path, but that it was inadvertently left out of the schematic. I love that someone took the time to explain the differences between the relay modules designs. I know a few people who think they're all the same, so they just recommend people always buy the cheapest.

[@farhat143ash]

very good video ! Thanks!!!

[@garymazzataz9350]

thanks for the video, now i know what the JD-VCC is used for i was going to use this relay for turning on a second PSU for computer as before i just use a relay and diode drive 12v dc from the main PSU and been working ok for years i just like to add a bit more protection

[@repairchannel]

Superb. Thank you!

[@frankp.2831]

Thank you for the excellent and clear explanation. Regarding relay module two, would it be possible to isolate relay and signal power by discarding the jumper and applying DC+ to the DC+ terminal for the relay coil (or the LOW pin of the 3 pin jumper) and signal power to the middle pin of the three pin jumper (either DC- or DC+ depending on whether we want to trigger high or low). Edit: I tried it and it works!

[@rafagarcia5880]

Hi Brad, From what I understand, if I'm not using an external power source, it's not possible to reverse the pins in order to activate the relay when the pin is high or is it? I'm talking about what you discuss at 5:35 of the video. Thank you for this really great video, I've understood a lot thanks to you!

[@odiliomartinez6811]

This is a great video...question...is there another way to set the relay from input low to input high?, the option you mentioned would only work with a single relay board, i'm using a dual relay board. already try to set the output GIO pin to high but it did not work... thank you

[@mowtown75]

Thanks, it helped me with solving the problem of the light being on when the relay lost power. I left one wire in the centre then moved the other to the opposite side, (which made no sense based on the Com, NO, NC schematic you showed). I then had to change my code to send LOW to actuate, and the HIGH to turn off. My wires are therefore now in I_ ( whereas before they were in ( _I where ( is the centre. Hmmm what I have done works for me but makes no sense to me.

[@zandanshah]

Very well done.

[@jaimecasimsiman3581]

Thank you for this video sir it so related for what im seaching. Can i use this board sir from audio out of the cctv camera so that i can trigered 24 volts alarm and lights from the output of module thank you

[@RayAteMushrooms]

Best video about relay so far, I wonder is it necessary to use opto-isolator when they share the same ground or even same source? Also it would be great if you also mention the resistor values.

[@AztecWarrior69_69]

You want him to list ALL of the resistor values for EVERY relay module out there?

[@RayAteMushrooms]

@@AztecWarrior69_69 Yes, it’s necessary for a schematic. I can send you those values if you want.

[@arun.sekher]

Thanks for the video, very informative. I would have liked to see the optocoupler based relay driver schematic with component names and values so that I could have tried making my own in a custom PCB.

[@Ron-pe4bp]

2:00 Can you really be sure those 3mm -wide traces can carry more current that the 1-1/2 mm wide ones? Can you know the thickness of the copper somehow? Excellent video, btw.

[@anatoliytrifonov9812]

Will be good to have the calculation on the resistor, diode, transistor.

[@RandomTorok]

I've got a small digital relay that I can't get to work on 5 volts. It takes a trigger larger than 5 volts to cause it to go high. I've currently got a 12 volt battey pack triggering it. So I've got the 12 volt battery pack acting as my mains current going to an LED. 5 volts coming into the relay side. And a line from a switch to the 12 volt on the trigger. When I hit the push button 12 volts goes to the trigger and triggers the relay allowing 12 volts to go to the LED. The relay is supposed to handle mains current but I doubt that I want to use mains current to trigger it.

[@marcello4258]

really useful brad thanks for that. can you give us some tips how to find good quality relays? dealing with 230V I want to avoid bad quality components which may cause a fire in case they break.

[@veda6165]

Is it possible to use a relay module to programatically switch power source of arduino from a DC power supply to an external battery without loosing power on the microcontroller, thus making it uninterrupted? I hope you can help me.

[@ezekielchery6892]

Is it okay to use the relay with the high and low switch with an external 5v power supply while sharing the ground from the relay/power supply and microcontroller. Im trying to connect my xiao rp2040 which is 3.3 volt and a 5v 30a relay.

[@RixtronixLAB]

Nice video, thanks :)

[@EnduroNerd]

This was a great tutorial. There is just one big problem with this safe option (8:20). You have THREE power sources hooked up!? I am trying to create a small project where I drive a traffic light from and arduino. I have a dual relay board. I really don't want to have 3 power cables running from the device. Ideally, I'd like to plug in my 240v mains and have it run the full system. Please could you create a demonstration to show how you would accomplish this in a safe manner (for me and the electronics).

[@EnduroNerd]

Please bare in mind that I have no formal electrical training. I have bought a few ardiuno starter kits and have bought what I think the necessary components are to get this all to work.

[@Ell-HR]

I know it's been almost a year but an answer is better than no answer so: First, you need to convert the 240v to 5v to power the relay module and arduino. If you want to fully isolate it, you'll need two 5v power supplies or one that outputs two isolated rails. One of these will power the arduino and the other the relay board. Power to the power supplies can be provided by your incoming mains that you are switching with the relays. This will let you switch it off of a single unit without any external supplies.

[@JeffMusicFL]

Thank you for the video Brad! I'm wondering if I can use a single power supply to power both the relay coils (JD-VCC jumper removed) but also the arduino. I guess technically the arduino wouldn't be completely isolated from the coils BUT at least the coils would be getting their power straight from the power supply instead of possibly overloading the VCC pin on the arduino right? I'd also like to know if I could possibly go a step further and use that same power supply to also provide the power on the relays themselves (only intending on turning on 5mm LED's) so basically I'm trying to use a single power supply to power the arduino, the relay coils, and the LED's connected to the relays. Starting to think maybe I could've just gone with a different module like something using mosfets? Still kind of a beginner so any suggestions are welcome! Thanks for your time!

[@rubenvaneupen7327]

Can you explain how to connect the high voltage DC circuit? I want a 12V circuit: so - from the battery goes directly to the load -. And + from the battery goes first to com pad on the relay, then the the NC pad on the relay (if you want normally closed) connect to the + side on the load. Is that correct? My relay does not seem to have an external power supply input. Only 5V from the receiver servo wire.

[@Hollywood4Fun]

I have the red relay. I'm trying to figure out how to get it to replace the trigger on my plasma torch for CNC use. I have the MKS DLC 32 control board. The instructions suggest I use the spindle output as the trigger source. The debt connection is 24 volts since it outputs whatever the power supply is. I just want to use that 24 volt spindle connection to trigger the relay which will finalize the wire connection to the plasma machine. Can you tell me how to do it in terms that a caveman could understand? Thanks. There's two wires that travel from the plasma machine to the trigger on the torch handle. Squeezing the trigger simply closest the connection. That's all I'm trying to do.

[@eddiemolina657]

Is JD-VCC is the (+) terminal for the collector of phototransitor, anode of the diode & P2 of relay? Pls reply

[@AztecWarrior69_69]

What software did you use to create the animations.?

[@Presso99]

educational video... thank you

[@hensonbl]

Thanks for watching!

[@ArchyGameDev]

Awsome video. Can you do a tutorial on how to read schematic and electronic?

[@hensonbl]

Thank you. I appreciate the recommendation.

[@hamoudihamoudi-gh5xy]

l have quation ,you can put the GND of optocoplor with the GND of the transistor. thanks

[@starstar71981]

What is better for a 12v vehicle application say 3amp. A standard automotive spdt or a microcontroller. Been trying to find a comparison but I can’t. Just knowing that the automotive relay uses electromagnetic only. Thank you

[@Mrmath76]

Nice video bro would you please explain us how the nrf433 hz relay module does work🙏

[@robinhooodrh13s23]

You give me a great vision thanks a lot But do you have explanation for this? When I turn on the Arduino board esp8266 and at same time connected to doubled relay WiFi can't connect Only connect if I unplugged gnd and 3v pins So each time I want to turn on board must unplugged gnd and 3v pins

[@garrybrewster5821]

either NPN or PNP will work for me switching RF signal inputs and outputs

[@screeningstudio3868]

Hi thanks a lot. Thanks to you the relay is working on and off according to the job, its all work fine, but when i turning on my plasma cutter, the relay only work about 10% of the project then my stepper motor suddenly stop moving and on the lightburn its show busy and pause, is it because the relay is 10 Amp maximum and the plasma cutter i use is 40 Amp? Is there any way make it work?

[@aatmajbarbhaiya3228]

what if i have to use a 15-0-15 V at 300mA rating transformer connected to a IC L7805CV Voltage Regulator operating at 5V DC output?! i did this but it resulted in a humming sound when the relay was turned ON, and heating of the IC circuit.

[@bourgeoise2350]

nice.. do you have circuit diagram of this?

[@simoncote3429]

Hi, please, can you get a 5VDC output? i want to use this as a safety relay so i want 5VDC in, 5VDC out

[@contextualcoding1884]

Awesome!

[@mikelunsford7462]

What type of signal activates the relay? 1 vdc? A frequency? Or any detection on signal? Does anyone know off hand. I'm not driving mine with Arduino, I'm using BT

[@joew4202]

You would need a 24 volt signal to activate a 24 volt relay

[@mishatagavor]

What are the chances of tarying a fire by connecting 110v to this full time using this as an interruptor for a power strip?

[@WhiteHairOldMan]

Best video I found to describe these boards. Are there any other benefits to using a separate power supply on the JD pins? I'm controlling five 24vac solenoids. Tripping them with a delay of 1 to 2 seconds between each solenoid. I'm having weird issues with the delays hanging (locked up) or acting like there is no delay where a few of the solenoids will trip like there is no delay. I'm thinking something is feeding back into my Arduino that is causing this problem and was wondering if I isolated the power that this might help.

[@hensonbl]

Thank you. One of the first places I look when I start to see unexpected activity is "power". When your micro isn't getting enough power or you are trying to draw to much power from the board, it will start to act in unusual or unexpected ways. If you are not using a separate power source to supply your relays, how much total current are you trying to pull from the board? Do you have all of the relays in an active high or active low state?

[@Rimsey1966]

Have you got a flyback diode or suppressor on the load side?

[@cyber_john]

Hi Brad, what software suite did you use to create this video?

[@hensonbl]

Adobe Premiere and After Effects

[@jam2031]

cant i connect an external power supply to the dc+ pin in relay module 2? or external power supply to dc- and dc+ for that matter?

[@last1standing22]

Did you ever find an answer because I have the same question ?

[@jam2031]

@@last1standing22 no i haven't, can i ask why are you asking this? why dont you just use module 1?

[@saintpeter1802]

hello teacher What is the wire that goes into the roller? Is it phase or negative? or doesn't matter

[@dhiu17]

could you tell me how to calculate the 2 resistors in the relay one circuit?

[@charlesbenedictt.durano1510]

Awesome! Can the relay be the cause why my arduino keeps crashing? Im using it on my lamp and ac motor

[@Dralsoft]

Is it possible to power the arduino from the relay?

[@Supriyadi17]

How to implement this method in multiple relay?

[@hensonbl]

You could drive multiple relays with an external power supply, and then turn them on and off with different GPIO on the micro. This would require utilizing the relay that enables you to separate VCC and JDVCC.

[@gabrielsiciliano6730]

All my comments based on Relay Module One. Tks.