I'm doing something in where I need to multiplex 6 7-segment displays. About doing it, I found things like this:
And things in where the same thing is done without the transistors, just by connecting the cathodes directly to pins of the microcontroller. What's the difference? When should I need the transistors? Is it because the microcontroller couldn't handle current for all the LEDs?
I'm using an Arduino with an ATMEGA328, if that's needed for something.