CHAPTER 5 Combinational Logic Analysis

Digital FundamentalsDigital Fundamentals

CHAPTER 5 CHAPTER 5 Combinational Logic AnalysisCombinational Logic Analysis

Basic Combinational Logic CircuitsBasic Combinational Logic Circuits

Basic Combinational Logic Circuits Basic Combinational Logic Circuits

• AND-OR LogicAND-OR Logic• AND-OR-Invert LogicAND-OR-Invert Logic• Exclusive-OR LogicExclusive-OR Logic


• AND-OR LogicAND-OR Logic


• AND-OR Invert LogicAND-OR Invert Logic


• Exclusive-OR LogicExclusive-OR Logic

Implementing Combinational Logic Implementing Combinational Logic

Implementing Combinational Logic Implementing Combinational Logic

• From Boolean expression to logic From Boolean expression to logic circuitcircuit– Given a Boolean expression, create a Given a Boolean expression, create a

logic circuit that implements that logic circuit that implements that expression.expression.

• From truth table to logic circuitFrom truth table to logic circuit– Given a truth table, create a logic circuit Given a truth table, create a logic circuit

that implements that table.that implements that table.

The Universal Property The Universal Property of NAND and NOR Gatesof NAND and NOR Gates

NAND and NOR gates are “universal” because they NAND and NOR gates are “universal” because they can used to produce any of the other logic functions.can used to produce any of the other logic functions.

The Universal Property of NAND GatesThe Universal Property of NAND Gates

• NAND Gate as an InverterNAND Gate as an Inverter


• Two NAND Gates as an AND GateTwo NAND Gates as an AND Gate


• Three NAND Gates as an OR GateThree NAND Gates as an OR Gate


• Four NAND Gates as OR GateFour NAND Gates as OR Gate

The Universal Property of NOR GatesThe Universal Property of NOR Gates

• NOR Gate as an InverterNOR Gate as an Inverter


• Two NOR Gates as an OR GateTwo NOR Gates as an OR Gate


• Three NOR Gates as an AND GateThree NOR Gates as an AND Gate


• Four NOR Gates as an AND GateFour NOR Gates as an AND Gate

CHAPTER 5 Combinational Logic Analysis

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