MP1584EN 5pcs Mini 5V Buck Converter Board - 5-30V to 5V, 1.8A Output, Small Size, Black

I have used a couple of this for some esp32 projects where I need 12v to power LED. I have used this to regulate the 12 V to 5V and power an esp32. Something I like is that they are very small.

I used this as part of an ESP32-Cam project and found that it performed much better than a similar unit with adjustable output from eBoot -- even though they both use the same MP1584EN chip. In my case, a super capacitor was supplying the input voltage and when the voltage dropped too low this board with fixed output voltage shutoff. The adjustable version did not which meant when power was restored, the ESP32-Cam was not functional until a reset. Because this board cuts the power, when power is restored the ESP32-Cam starts up normally and is fully functional. This could be a consideration for solar powered projects as well.

Compared these with multiple other units to test with a low current draw and this was this best I tested. With a 12.02V input, the unit output 5.174V, and at a current draw of 24.44 mA from the output side, the input side had a draw of 12.36 mA, which gives about an 83% efficiency. At 475 mA on the output side, the input was at 220 mA, which is approximately 91% efficient. With no load, the current drain was 806 µA (at 12.02V). The results of how well these inexpensive boards performed were a surprise, as were the poor results of more expensive buck converters, such as Adafruit's MPM3610 board.

... so it's cumbersome to breadboard.You CAN solder in some pins & bend them to sorta fit a 0.1" grid.Holes are 8mm x 14mm, so 0.315" x 0.551".To quote Austin Powers: "Seriously, who does that?"Would it have killed them to make the pins 0.4" x 0.6" ?

I have a few hundred partly used C batteries that are all at about 1.4V from a piece of medical equipment that requires a fresh set every day. This regulator lets me hook up six of them at 8.4V and drain them to under a volt each, giving me a constant 3.3-ish volts the whole time.I didn't read the title and description (4.7V-23V) closely enough and started with three batteries at 4.2V, which caused the regulator to output only 1V. I contacted the seller and they replied very quickly and even tested some regulators at 4.2V to verify my results even though I clearly misread how to use them. Very impressive response!

I got the 5v model, and have tested a few, they output 4.72 volts under no load, this is just barely within range of what most USB devices will tolerate, and I'm sure it will drop under any load. They are nice and small but don't work very well. The resistors are too small to manually replace.

I was planning on soldering pins into the holes to use on a breadboard, but it looks like I can only add one pin to hold it stable in the breadboard, then solder wires to the other three holes and crimp pins on the ends of the wires to go in the breadboard.

Running from 9v these little buck convertors produce a steady 3.3v output no heat issues or failures at around 70% duty cycling.