Circuit Design Example: Add one to a 2 bit binary number

- Problem description:
Construct a circuit that has 2 inputs and 3 outputs, the 2 inputs represents a 2-bit binary number and the 3 outputs represents the value that is equal to the input number plus 1.

- First, we find the boolean function (in table form) from
the description above:
a b z _{2}z _{1}z _{0}- - + - - - 0 0 0 0 1 0 1 0 1 0 1 0 0 1 1 1 1 1 0 0 - Now we can apply the circuit construction algorithm
on
**each of the columns**to obtain the circuit: - You can experiment the circuit with this demo file:
click here
- Notice that
**individually**, the logic functions for each of the outputs z_{2}, z_{1}and z_{0}, is not very meaningful. But**joinly**, they represent an outcome that is equal to the input + 1.