I learned today that you can get a variety of digital circuits out of a chip by running the 5v VCC through a variety of steps in order to achieve a desired output.
XOR, NOR, and NAND gates, apparently, are inexpensive, and often make good trade-offs when it would be too expensive to add an extra NOT gate.
Digital outputs demonstrating the following boolean functions.
Double NAND = NOT
ab = ((ab)')'
NOR = NAND
a' + b' = (ab)'
XOR
(a'+b) = (aa)' + b
XNOR
ab = (ab)'(ab)'
XNOR 2
Boolean expression results in 1
(just plug in a and b to ground)
same truth for an XNOR gate)
