Youmile 5 pcs AC-DC 12V 450mA Buck module Power Supply Buck Converter Step Down Module 5.4W Transformers with red and black cable

Installed it. Tested it. Worked fine. There's a nice bright green Led to let you know it's working. Ive got one controlling a heating element.

I've used similar switched mode power supplies and they tend to be of a similar design (the data sheet for the controller chip can be found on the internet). First off, it does not come with (or show) CE compliance so safety could be a concern. Missing is either a input fuse or more typically, a fusable resistor; power factor correction etc but then this is a minimal cost design. One concern is with the transformer construction - I did a windings isolation test to 600 volts with no insulation failure so a pass on the tested unit. Typical failings over time are the input and output electrolytic caps and the good news here is with the input cap indicating a higher than expected temperature max rating. Optical feedback is used for output regulation and the PCB has isolation slots where required. In use, the test unit has now run continuously for over 500 hours and operating temp has been fine (not in an enclosure) so looks good for DIY type use, with the standard precautions taken.

Perfect for low current audio projects

Voltage too high, 13.8 voltage. I burned my arduino pro min board.

Although small and should supply enough power for an IoT device, I was hoping that they were switched mode PSU's. However, they are simple linear PSU's with a 220VAC transformer and basic full wave rectifier plus electrolytic capacitor smoothing. Output voltage appears to be regulated by a simple zener diode (though I havn't checked the part number). Thus they do not fit the purpose intended. I had intended that the safety issue of the presence of lethal voltages could be addressed by encapsulating this PSU but I am now looking for a fully encapsulated switch mode PSU.

Positives:- Works well- nice 5v output- the spacing of the AC is 5.08mm for standard terminals to fitNegatives:- Not enough clearance for the 5.08mm PCB terminal to sit on top of the pcb. Works fine at the bottom.- not enough clearance for the green capacitor, it sits 5 miles over the pcb… You need to bend it and place the capacitor the way it is set on the product pics, i.e. the body of the cap is parallel to the pcb.For the price, I’m happy with the module, despite the component clearance issues.I’ll be using it for ESP32 and 8266 projects, so this is ok wattage-wise and can fit in a small junction box. If I find any issues I will report back.

4 stars, one pcb come with output shorted, otherwise they are good and cheap.

Voltage too high for my Arduino project.