Help to ac regulativ by arduino

Hello

I started a new little model railway club where we're going to run with an analog system, not digital yet, and I have in my mind to do some control with an Arduino driving the flow and it is ac voltage research and I would hear about there are some who know where I can get a diagram for such a regulator and it should work between 0 to 18 volt :slight_smile:

Regards

Tjalfe