Hi,
I would like to use the UNO in the car and need to make shure the voltage peaks from the car does not kill the board (And I do not trust the connector regarding vibration). Therefore I plan not using the UNO internal voltage controller but an external with according capacitor, coil and diode suppressing the voltage peaks. A LM2940 is the voltage regulator down to 5V.
Can I feed the 5V from the 2940 directly into the 5V pins on the board or does the UNO voltage controller on the board is being overstressed?