I am using an Arduino Uno together with a L293D motor driver to power 3 tiny motors.
The problem is that when I connect it with the PC via the usb cable I get 5v on the external power pins. I removed the VIN jumper as instructed.
Is it normal behaviour?
It annoys me because I have a 12v led switch to power the PSU that feeds the external power of the L293D and it is always lit by USB power.
If it is normal behaviour... how can I stop the 'backwards' power?