Review on 🔌 ICStation Relay Power Switch Module with Optocoupler - 2PCS | High-Level Trigger | DC 3V 3.3V | For ESP8266 Development Board Arduino by Daniel Pesicek

They work well with 3.3V microcontrollers. In my limited testing they can safely and fairly reliably switch 12V/5A. I plan on going through them about 8 times Amplifier; So far so good, but hopefully not close enough to the listed values to cause problems in the long run. The only comment I have should be pretty obvious to anyone using a relay module like this, but I made that mistake and think it's worth calling out. The bare metal relay pins and screw terminals protrude at about the same height on the underside of the circuit board. So if you put this board on a metal surface with the power connected, everything will be shorted out and everything will likely break. . You're lucky if you only lose the relay module, so either pay attention to the metal surfaces or put foam feet on the boards.