Combinational Circuits (5)

• A combinational circuit consists of logic gates whose outputs at any time are determined by the inputs using logic operations.
• For n input variables, there are 2ⁿ possible binary input combinations.
• For each binary combination of the input variables, there is one possible binary value

on each output.

•  Hence, a combinational circuit can be described by

1. a truth table that lists the output values for each combination of the input variables, or

2. m Boolean functions, one for each output  variable.

Combinational Circuit Analysis

• Analysis of a combinational circuit is the determination of the Boolean function that

the circuit implements.

• The analysis starts with a given logic circuit diagram and ends with a set of Boolean

functions or (equivalently) a truth table.

 Example: