HiLetgo 2pcs 5V One Channel Relay Module Relay Switch with OPTO Isolation High Low Level Trigger

I've attached a photo of the relay module schematic. I Ohm'd and traced it out. Now the function of the 2-pin jumper is fairly clear. In my case, I want the coil to be active when the input (IN) is a logic high (3.3V) from an Arduino. Thus, I want the jumper as shown in the schematic (photo).

Wiring was super intuitive and everything just worked. I was able to power, ground and provide signal all from Arduino and then pull 12V DC from a 4A dedicated power source and connect it directly to the 12V DC magnet when the relay receives a signal. Perfect solution for my secret bookcase door project!Only note was that the relay screws needed the perfect sized screw driver because it felt like it was going to strip with the one little screwdriver I use for everything so I had to get a new small screwdriver kit and then i was able to repeatedly install and change configurations on this board without any problem.

Used for Ham Radio Amp InterfaceI needed to isolate the radio from a vintage Linear ampthis is perfect,used on a SB200 and an Ameratron linear amp.I used a 12 volt one powered by a 12 volt power supplyand I used the 5v one for battery powered interface.

I ordered 8 of them but even tho you can change the switching from high to low (very cool feature btw), you cannot use them with a RC Remote control unit (ex: Flysky or similar).

With the caveat that its only been running a few hours, seems good so far. Very simple and easy to connect to my 3.3 Volt Arduino Nano 33. I used 5 volts to power the relay and a 3.3v pin for signal and that seems to work just fine.If I wanted to nitpick, it would be nice if it had solder holes and not just screw terminals. Screws are good for my breadboard prototype; not so much on my final design. So I will try to remove the screw terminals by de-soldering.

As per usual another solid product from HiLetgo. I have been ordering from them since 2020 quite often. It started out because of the price and reviews mostly good. Now I always try and use this company from resistors to diodes to relays ect. I've only received 1 bad ESP32 and all it took was a soldering iron and 30 seconds and I was on my way. I ordered their relays 3 years ago and the same ones are going strong. So; I ordered these and wasn't let down upon opening.

I am using this unit to trigger a plasma cnc setup. Connecting and setting up the unit is simple and easy. Just look at the marked input and output connections and your all set!

Lasted a little over 1.5yrs