Firstly, apologies for these basic questions.
I've got a 10A V5 power supply that's primarily there to power a bunch of LEDs but I wanted to also use it to power an arduino mega 2560. I read that:
5V.This pin outputs a regulated 5V from the regulator on the board. The board can be supplied with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it.
I'm a bit concerned that it's not advisable to supply power to the 5V pin. Is it just because you could get the polarity and voltage wrong and wreck your arduino or is there something else to be concerned about? If it's the later , should I create a USB B cable with 5V coming from my power supply?
The next question I have is, if I'm powering the arduino through 5V and then want to program it through the USB can I keep the 5V pin connected and let the arduino choose the power source or must I always disconnect it before connecting the USB cable?
(I'm trying not to blow up my arduino mega)