I purchased these in the link below the price and size are correct. for the life of me I can't figure out how this thing works.
AC DC Power Supply Buck Converter Step Down Module
I was reading that a simple voltage divider could do this but I believe that was higher voltage dc to lower voltage dc not AC
This device is sufficiently cheap and small enough for me. I want to add it to a pcb with wire terminals for the ac input and then I need to route the lower voltage. (for the life of me I don't see an in or out on this thing)
I would not mind building my own circuit if it's cheaper or smaller.
Please let me know
Since you received no schematic with these boards and no user manual as to how to use them
I would suggest that you not use them.
You could attempt to draw the schematic by going by the traces on the PCB.
The PCB may only be front and back and not have more layers internally.
If you happen to have an oscilloscope and a good voltage meter you could take voltage measurements and look at the various signals present on the board to determine if they are indeed worth using.
In looking at these more closely there is one piece of information that is absent, How many amps can this provide?
There is no amperage rating.
It is a glaring omission.
If you can return to amazon and find a wall wart for the arduino.