I bought two of these and they work exactly as advertised. Great quality build; highly recommended.
I also had technical questions about powering LED's and how to get the highest possible efficiency for my application. Enrico went above and beyond anything I could expect. He looked at alternative parts I was considering, caught some "gotchas" I had missed, examined my schematic and offered a ton of advice for my particular circuit. He's very responsive, and his expertise is top-notch.
July 22, 2018
Useful product, works as advertised. Quality construction.
Works very well as a constant current power supply for LEDs. I would like to make a couple of suggestions: 1) Explain how the LED forward current, Ifw, is determined. I had to go all the way to the LM3405 to get this. Not hard but will be easier for beginners to explain this. The forward current is set by R1 according to the formula: Ifw = 0.205 / R1, or R1 = 0.205 / I For example if your LED needs 500 mA, 0.5 A then R1 = 0.205 / 0.5, R1 = 0.41 Ω
2) If you ever re-spin the board and since there is some space available, maybe add some extra pads or holes to make it easier to experiment with R1. Since the values are very small a few pads in parallel may help to get the needed value. In my case I needed 360 mA, R1 = 0.57 that was approximated with a 1 Ω in parallel with 1.5 Ω