The 7403 IC package contains four independent positive logic, open collector, NAND GATES. Pins 14 and 7 provide power for all four logic gates
Outputs of one gate can be connected to inputs of another within the same chip or to another chip as long as they share the same ground. The figure to the left illustrates a basic circuit showing how to wire inputs and using LEDs to display outputs.
NAND GATE Logic-Rules:
If both inputs are HIGH then the output will be LOW, otherwise output will be HIGH.