Xiuxin 2pcs 5V 8 Channel Relay Module Board for Arduino PIC AVR DSP ARM

Used this with my Arduino/Elegoo set to control 110-volt circuits. Never had an issue with them.

The two 8 relay parts arrived quickly. Build quality was top-notch with all channels working on both boards. I used these to switch 12V at 4A and so far so good. The circuit board around the relay's common output pin is milled to isolate this pin from the 5V coil pins. The NC and NO output side pins are way on the other side of the relay package. The optoisolators ground, however, is routed all around the optoisolator, from the opto part output side to the logic level input side. Logic drive is active low so the digital board driving this would need only to wire a +5V logic and the logic device pulls a control input low to activate a channel. Anyhow, it looks like a missed opportunity to isolate relay coil emf kickback or a failing relay structure. The optoisolator output side, in all cases, still needs a +5V power source. Even with this in mind, I gave 5 stars because driving a small relay coil using a non-optoisolated driver would be good enough.

As another stated, these get stuck after a few months of operation.Pretty big headache and can certainly ruin any project you may be doing without notice!

Arrived with no documentation. They're active low. An inline current measurement showed about 3mA (.003 A) of current draw.

Overall these work fine.They are LOUD relays. I was frustrated that they don't have NO or NC marked. I mean, I can figure it out with a multimeter, but it would have been nice for them to be marked.

As usual, no instructions by manufacturer, have to rely on someone else's write-up.Power consumption of the relay coils on high side. Make sure you have a well regulated supply, or use a separate supply for the coils. There's a pin for it...

Used with a Wemos D1 Mini to control latching DC valves (fairly low voltage and current, 12V 2A or so). Have not tried high voltage. Trigger from 3.3V digital IO pins on the EPS8266 work great. Board itself needs 5V

Purchased 6 of these (3 2-packs) to drive a 40 channel christmas lights display off an arduino mega. Haven't built the display yet, but the boards all tested out fine. Dropped two stars from overall / ease because 2 of the boards got crunched in handling and I had to repair the pins, but after redoing the connectors, the boards tested fine.