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Question: How do you adjust the output voltage of this converter to a desired voltage, say 4V for example
Document: I tried a few other buck converters while attempting to drive a dozen micro servos, and they would all overheat when trying to run that much current. I'm using this to get 3.3V to 12 TowerPro SG90 micro-servos, and it does a great job while not warming up very much at all. This is a little bit larger than the other converters I tried, but it's worth it, and easy to adjust the output voltage if you have a voltmeter handy.
This little converter works great. I'm using it to reduce the speed of a couple of 24 volt high power fans. It doesn't mind the inductive load and the output has relatively low ripple on the scope. Under load it warms a little. My only complaint are the cheesy wire connectors for input and output. They are flimsy and not mounted well to the board, so they twist when you clamp down on the wire.
This converter is accurate and consistent. I set my output at 5.1v and the converter reliably puts out 5.1v regardless of the input from the vehicle (13.5v while the engine is running, or 12.7v when the engine is turned off).The only thing I don't like about this converter (other than it not being domestic) were the wire clamps for the inputs and outputs. I found the mounts to be highly unreliable.
This converter work just as it is supposed to, it is compact and doesnt put off much heat. I purchased 3 units. They appear to be very sensative to shorting. Easily toasted. But that said,  ive been using the other 2 for several weeks without issue.
Puts out 5.5V from my car electrical system's ~13.5V. It has an adjustment on it, but I wasn't sure how to adjust. I think I know now but instructions would have been nice.One of the screw terminals for the input was stuck, so I de-soldered the terminals from the board and just soldered the wires from my hub directly to this convertor.
This unit works very well. I adjusted the voltage down to what I needed, and it has remained rock steady since then, no fluctuation.
This was perfect for my remote power to camera application. I read that the terminals were poor but I found them to be solid and hold well, the unit keeps a very steady voltage (7.52v) for my camera supply. Long use did not cause any heating of the heat sinks.
This units is just what i needed! I needed to be able to use my computer power supply 12v rails to power some water pumps and some fans attached to radiators. I wanted the fans to run slower and quieter, so I could turn down the voltage to the fans to 7v with ease! I have big radiators with big fans that pull 100W at 12v, and they were too loud and overkill for most situtations, but now its perfect! Voltage holds stable for the most part.
They are close together and easy to short if you're not careful. It's still worth 5 stars. I'm buying 2 more.
One of the heat sinks / transistor gets way too hot, even at half the rated current. The blue screw-down terminals are cheap; the plastic on one came cracked and both are haphazardly mounted.I would not buy this again - I'd rather build my own in the future.
Answer: You can adjust it with the potentiometer on the board, but you are going to need a small flat head screw driver and a volt meter to do it, there is no voltage read out on the board itself.