I am in the midst of trying to figure out how to best switch the power input between getting power from the serial connection (i.e. bootloader / programing) vs. getting it from external power (5VDC). I have seen other implementations such as the RBBB rely on nothing more than strip headers to accomplish this, i.e. a 3-in 0.1" strip header with a shunt. However, what are the power limits of such headers and shunts? If a maximum current of 1A were to pass through there @ 5VDC, would it be safe?
When looking through datasheets on slide switches and other alternatives, should I be focusing on the ampere rating or would VA be more applicable since my voltage is so low? I'm inclined to limit myself via amps because I'm cautious...
would it be safe?
There is no danger involved with 5V @ 1A at all, being safe is not a problem.
The problem is the voltage drop, each connector has a finite resistance and current flowing through that causes a voltage drop. At some point someone takes a view that for a certain current the voltage drop is unacceptable and so says that what the current limit is. But in these situations it is not a limit as such, nothing is going to go bang, nothing is going to burst into flames.
When dealing with pin headers and power it helps to parallel up two or three when you can. I have used two gold plated pin headers to connect a current of 5A for my 3D printer extruded heater and I don't notice any heating up of the connectors.
Thank you, Mike!
I also wanted to thank you for your suggestions regarding the protection of the Analog input on your site.