Polarity of Keyestudio W5500 Ethernet Development Board Power
I just wanted to put an answer here in case anyone else is looking for the power parameters of this device.
So the inside of the barrel connector is positive, and the outside is negative.
Thanks to the helpful comments, I went through with a multimeter, testing the LEDs, but i saw that the tiny amount of current flowing through the diode was enough to illuminate it. Once i worked out which direction the electricity flowed through the diode, i connected one lead of the multimeter to D4, and one to the ground and i saw that the diode illuminated.
This told me that since the black lead was connect to the ground and the red was on the other side of the diode, that the polarity must be (+) in the center and (-) around the outside.
I then cautiously powered up with 3v instead of the usual 7-12v and the diodes illuminated, which is good, i'm guessing they wouldn't otherwise, so then i powered it up with 7.5v and the board seems fine.
If anyone has a better way of doing it than this please leave an answer.