4pcs DC 12V Relay Module 1 Channel Relay Board with Optocoupler Isolation Support High or Low Level

These work perfectly fine with a 3.3 volt trigger. No problem at all.

I bought these to use for my CNC plasma table and it works great with no issues would definitely buy again if I needed to

Product works as expected . I have to used it to control solenoid using float value for aquarium. Connect the 12v DC power directly to +/- terminals of relay.. Connect one float wire to signal interface and other wire to positive terminal. Now you can use this relay to make it NC/NO based on your requirement

Relay module worked great for off grid camp house water system comprised of two 55 gallon drums located inside building. Filling from outside collection tank without constant monitoring can cause an unpleasant overflow! The relay with a fish tank level switch in each drum solved overflow risk! The connection terminal screws are very precarious! Should supply phillips driver that fits! Otherwise, happy with new install!

I use this device to provide a mute circuit in a bias T I made for a remote antenna pre-amplifier. A control line which goes to ground when my transmitter is activated, connected to the low input, triggers the relay. Works well. Edit: I have built two different mute circuits using this device. They work well. But a few learning points have emerged. As other reviewers have noted, the screw terminals merit close attention to ensure they have adequately secured the wires you connect to it. Secondly, there is a voltage present on the sense input equal to the supply voltage. It appears to be a very high impedance source. That phantom voltage may affect the circuit you have it connected to. It did in my case. I solved this by placing a Schottky diode at that input port, which isolated the other equipment. I still recommend this module. Just keep these other two factors in mind. They are easily resolvable.

I am very happy with these small devices. I only tried a few of them and they work great on my bench! Good price for 4 of them. Only negative thought is the screw terminals are not the best, they do work, but not very good. If the screw terminal does fail over time, I will just solder the wire in place and ignore the terminal. Update Mar 03, 2023: My only complaint is the mounting holes on the board. The board is too small and the holes are too close to the edge of the board, and too close to the terminals. Difficult mounting and using screws. They need to make the board "bigger" in size to allow more spacing for mounting.

Works really well, good quality

Working after correctly configured the the relay