Combinational analysis
All circuits fall into one of two wellknown categories:
In a combinational circuit,
all circuit outputs are a strict combination of the current
circuit inputs, whereas in a sequential circuit,
some outputs may depend on past inputs (the sequence of
inputs over time).
The category of combinational circuits is the simpler of the
two. Practitioners use three major techniques for summarizing
the behavior of such circuits.
 logic circuits
 Boolean expressions, which allow an algebraic representation
of how the circuit works
 truth tables, which list all possible input combinations and
the corresponding outputs
The Combinational Analysis module of Logisim allows
you to convert between these three representations in all
directions. It is a particularly handy way of creating and
understanding circuits with a handful of onebit inputs and outputs.
Opening Combinational Analysis
Editing the truth table
Creating expressions
Generating a circuit
Next: Opening Combinational Analysis.
