Thank you for your comment… I keep your idea for a professional retraining ... :)    

Bonjour, Juste pour le plaisir un lien vers une vidéo de ma réalisation de ce beau projet. Quelques embuches mais baucoup de plaisir. Patrick D.

What an amazing project! You seem to know quite a bit about electronics, I think you should consider working on dynamic road signs.

Hello Knulldulski, in its typical application circuit the LM3409 requires 4 resistors, 3 capacitors, a p-channel mosfet, a schottky diode (fast recovery) and a power inductor additionally. Compare this to 2 resistors and a transistor and you probably know the answer. The LM3904 may be a good solution in automotive mass applications where you can spend multilayer boards with aluminium or copper inlays for better heat spreading, but clearly not for something handwired as a single test fixture in a DIY lab. klausb

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