Ok, so this is my first post since I'm new to this forum and new to electronics. (tried the search and unfortunately ddnt find something to help with my prob) I have a homework-activity on Computer Interfacing subject. And my problem is connecting, not really connecting but lighting-up my seven segment though a SN74LS47N IC. I'm pretty sure I connected the IC-to-7segment right, when I tested my seven segment using a multi-tester, it lits up which means it's OK and functioning. I also tested my SN74LS47N to check if it's functioning but it's ok also. I just dunno why it won't lit up when I put the things together. My supply is roughly 5v (from a parallel port), if I'm not mistaken. And no, my parallel port is not the prob since I use it to test our previous activity and it worked fine. Here is my schematic diagram, I already asked a friend and told him bout my materials but wasn't able to show him my schematic. He says it could be my resistors. Am I using the right resistors? or I got the wrong ones? Since 7 segment is also are LEDs put together, how come my previous activity worked fine using same resistors connected to an individual LEDs? I need some enlightenment.. please help tnx EDIT: forgot to label the Vcc of the IC. It's also 5v.