ABSTRACT

Digital electronics deals with signals that take only two possible values, a high value, which we usually write as 1, and a low value, which is usually written 0. A truth table shows the output of the circuit for every possible combination of inputs. Every combinatorial circuit has its own truth table and every truth table can be implemented with a combinatorial logic circuit. A 1-input gate has two possible states for its single input, producing 22=4 possible 1-input gates. The linguistic complement of AND is OR. The output of an OR gate is true if ANY of its inputs is true. Individual logic gates can be constructed from MOS FET transistors. Manufacturers produce a variety of such gates in integrated circuit form, with anything from a few gates to billions of gates in a single package.