Newbie level 1
I'm new to Electronics , i want to build a keypad which can display 0-99, by using 7400 IC series , so far i manage to build it to display a single digit using 7447 , 7 segment display, 7404 , 74147. I came across this project **broken link removed** and now I'm trying to figure out how to use 74157. Please help me . How can i multiplex this display using 74157?