Oiyagai 4pcs 12V One 1 Channel Relay Module Board Shield with optocoupler Support High and Low Level Trigger

I found this to be a solid product, especially for the price. I wanted to be able to use it for an input of 3V or 5V logic. Of course, the supply voltage must be 5V. If you are using 5V like an Arduino, you can choose to use either logic high or low to operate the relay using a small jumper between pins as shown in the product photo. If logic low is chosen, the input pin will be at a logic 1 at about 4.2V. Driving that to a low or ground will operate the relay. Because that voltage is there at idle, an operation using a logic low CANNOT be used with 3V logic like a Raspberry Pi or ESP8266. When choosing a logic high to operate the relay, there is no voltage on the input. A logic high of either 3V or 5V will operate the relay. I measured the current draw at 1ma at 3V and 1.7ma at 5V. This is easily handled by the Arduino for 5V and the Raspberry Pi and ESP8266 for 3V logic. Therefore, ALWAYS using logic high operation for 3V logic.

Or should I have said in the title here that these are "The bees knees?" Either way, thus far these are exactly what I'd hoped for. Clearly the price is good, and they arrived surprisingly fast. But if they were of sub-quality who would want a bad product that's priced well and comes fast if they don't WORK? Pretty much nobody and as far as my order I found the quality to be excellent (i.e. They are solid and work as you'd expect them to.)So count me in as a very satisfied customer, with my thanks to the seller. :)

Used the 12vdc relays for my 12vdc charging project. One for the charging and other to cutoff the load during charging. In a different 12vdc project used a lm358 circuit to triggering the relay in a over voltage cutoff which would cutoff it main 12vdc supply so it could not restart.

Arrived as promised. Great Product.

Got them right on time, it does the job perfectly well.

come da descrizione, funziona molto bene, specie se si passa dalla modalità H alla modalità L

It works but unfortunately one of them was faulty

Works great.

Top quality immer wieder