Students' Guide to Information Technology, 2nd Edition

Students Guide to Information

Technology

Combining logical operators

We can combine these logical operators (and the circuits which

represent them) in any number of ways. For example, Colin may

decide to go to the camp if:

(A OR B) AND NOT (A AND B) = 1

This means that he will go to the camp if

A OR B = 1, i.e. Ann or Barbara go

AND if

NOT (A AND B) = 1, i.e. if they don't both go.

So he'll go with one or the other but not both!

The truth table for this can be built up in stages. The first stage is to

construct the value for A OR B and NOT (A AND B). The second

stage combines these two first-stage results using the AND operator.

Here's the