I used the following HW-221 with an UNO to convert the 5V from pin D13 to 3.3V:
But instead of measuring 3.3V my multimeter displayed 5v, 6v,11v ,etc.. it was growing so I unplugged all before it explodes.
Are the wires correct? I also tried to put 3.3V then 5V to the OE (Output Enable) pin but it changes nothing. Maybe the converter has a problem?
EDIT: I tried with another one and it works. The first was defective