Review on ⚙️ Adjustable Onyehn Voltage Controller 1803BK by Dave Cavazos

Connecting these modules is simple: there is +/- for power and +/- for load. In my case, the load was a 30mA 80mm fan (that's a milliamp, not an amp). The polarity of the power supply and the fan must be observed. Two modules died instantly. One smoked, the other smelled hot, then stopped. I wouldn't waste your time and money on this. They are complete rubbish.