ABSTRACT
The main aims are to introduce basic techniques of combinational logic: To express the inputs and outputs of a system in binary form; To develop the relationship between these inputs and outputs as a truth table; To simplify the Boolean expression using algebra or Karnaugh maps; and to select suitable electronic devices to implement the required function. To see a little more clearly what combinational logic is, consider the example of a protective interlock designed to guard against misuse of an industrial machine. Suppose that there are three conditions to be satisfied before operation is possible: The workpiece is in position, adequate lubricant is available and a safety guard is in position. The function of the interlock is to check the conditions to see whether they are satisfied, and if they are all satisfied the power will be connected to the machine.
