Hello, Please see the attached schematic. I'm trying to construct a 5x7 LED Matrix (Column scanning) where each module has 4 LEDs. Please let me know if the calculations for the NPN-2n4401 are correct and if you think that this setup will work. Calculations derived from the equations here
Each row will only power 1 module at a time @ 20mA -> handled by the 2n4401 (20mA x1 = 20mA) Each column will sink up to 7 modules at one time -> handled by the ULN2803 (20mA x 7 = 140mA)
I feel like the calculations are well within the hardware's capability, I'm more worried with a flaw in the setup.
Thank you for any advice!