Review on 🔌 10pcs MakerHawk LM2596 DC-DC Buck Converter: High Efficiency Step Down Voltage Regulator, 3.2-46V to 1.25-35V, 3A Adjustable Power Supply Module by Andargie Waiker

The bottom of all circuit boards is dirty (first photo). Upon delivery, one of the devices in the bag was broken (second photo). Generally not the best quality. Although the units work fine. I recommend turning the screw fully counterclockwise before connecting the power supply. They are set at the factory to the highest voltage level. If you are using a low current power supply, plugging in that power supply will saturate the power supply. After connecting the power supply, turn the screw counterclockwise until you get the correct voltage. Requires a voltmeter or other means of measuring the output voltage. I tested this with 22V input and set the output to 5V, 9V and 12V. See the last three photos. I cycled the input power on and off and the output voltage seemed to stay constant. To test, I soldered pins to each connector and found that they fit well on the breadboard. The last photo shows the device that powers the Arduino Nano via Vin. Contact with controller output set to 9V.