Chapter - 10: Combinational Logic Design

Logic Circuit

1. Sequential Logic Circuit
2. Combinational Logic Circuit

1. Sequential Logic Circuit

   The sequential logic circuits are those circuits which also contain memory elements. In other words, we can say that the basic element of sequential logic circuits is the flip-flop. Registers and counters are the example of sequential logic circuits

2. Difference b/w Combinational & Sequential Logic Circuits

In combinational circuit the output only depends upon the present input. Whenever we change the input then output will be changed. Whenever in sequential logic circuit output does not only depend upon present input as well as they depend upon previous output

3. Combiantional Logic Circuit

   Combinational circuits are those circuits which are composed of logic gates in other words we can say that the basic element of combination circuit is the logic gate. The examples includes: Adders, Subtractors, Comparators, Encoders, Decoders, Multiplexers & De-Multiplexer

   Design Procedure
   1. The problem must be defined properly wit clear logic definition. Determine the number of inputs and outputs and assign symbol for each.
   2. Describe the circuit in terms of truth table
   3. Write Boolean expression from truth table
   4. Minimize the Boolean expression
   5. Obtain NAND or NOR logic if required
   6. Draw logic diagram and verify the operation of logic circuit manually or through simulation
   Design Example:

   {see page 11 of DLD part - 1}