I'm playing with a 7 segment display.
The following works on my breadboard:
5V -> 330 Ohm Resistor (same row, row 9) 330 Ohm Resistor -> Com Port (row 9 to row 15) h led (the dot/row 17) -> ground rail
I get the dot to light up.
However, the following does not light up:
5V -> h led (the dot/row 17) Com Port -> 330 Ohm Resistor (Row 15 -> row 38). 330 Ohm Resistor to negative rail (row 38 -> negative rail)
I realize that the row numbers are meaningless -- things just need to be on the same row. I've included them to make it easier to visualize.
So basically, if the circuit goes:
5V -> Resistor -> Com, then I can use the ground wire to light up any part I want.
If the circuit goes Com -> Resistor to Ground, I can't use the 5V to light up any part.
I'm not sure why given that all the stuff is in serial?