Hi, Rafael.Welcome to the Arduino forum.The relay pin "signal" is connected to the Arduino pin your program controls to operate the relay. The program may set the pin LOW to turn on the relay, or it may set the pin "HIGH" to turn on the relay. The H/L jumper is set to match the way your program sets the pin.The VCC on the right side is where you power the relay, 12 volts in your case. All the grounds, 12 volt power and Arduino must all be connected together.The left side of the relay is for whatever you are controlling, but you already know that.Paul
You need to show which relay module you actually have. Not pictures of things 'like' what you have.
Hey, Paul.Thank for the reply!Does that mean I cannot connect an external power supply to this relay to make use of the Optocoupler (is that white 'thingy' an optocoupler?)? If not, does the arduino still gets isolated from the rest of the circuit?RafaelEDIT:This is the kind of relay I tried to mention:It has a JD-VCC, VCC and GND pins to connect an external power supply. Will mine work the same with the H/L pins or it is something completely different? :/
The black, square things are the opto-couplers. One per relay.Your external 12 volt supply connects to the VOC pin on the 4-pin header. The in1 and in2 pins connect to your Arduino, just as I wrote before. The 3-pin header on the left selects how your program turns on the relay. High active or LOW active.And all grounds connected together to make complete circuits.Paul
Ok, I think I got it now!Just two last questions: 1) Since my Relay (The red one with H/L level selection) does not have inputs for external power supply, will my arduino be isolated from the rest of the circuit? 2) On the right side, does the signal Voltage needs to be equal to the VCC Voltage? In other words, can I connect a 5V digital pin from the arduino to the Signal input on the relay, while its VCC voltage is 12V?Sorry for asking so many questions and taking so long to understand, hehe.Rafael
BOTH RELAYS HAVE INPUT FOR AN EXTERNAL SUPPLY!!!!!!Paul
I doubt you have a reason to bother using isolation. The modules already have transistors and flyback zeners. By the time you build something worth isolating, you might then have enough knowledge about electronics to know how.
You might be right. I am not really sure if I need to isolate it, since it is only 3 12V solenoid valves. I just heard someone suggesting using an optocoupler but I didn't really asked why. Anyways, I'll see how it goes without isolation.Thank you.Rafael