1. Digital Computers Logic Gates & Applications

2. Digital Computers Types of Material (Electric Conductivity) – Insulator Rubber / wood – Conductor Copper / Gold / Iron / Water – Semiconductor Silicon / Germanium – Superconductor ???

3. Semi-Conductor Devices Wire (conductor) Resistor Diode – Electricity can go in one direction – used in rectifier (AC to DC), LEDs Transistor – used in (Logic Gates) – A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. – Used as Amplifier & Switching device Logic Gates – NOT,OR,AND, NOR,NAND, XOR, XNOR Integrated Circuit

4. Logic Gates GateSymbolTruth Table NOT Boolean ExpressionA’ or A

5. Logic Gates GateSymbolTruth Table OR AND

6. Logic Gates GateSymbolTruth Table NOR NAND

7. Logic Gates GateSymbolTruth Table Exclusive OR XOR Exclusive NOR XNOR

8. Universal Gates – NAND NPN-Transistors and Resistor

9. Constructing Gates with NAND

11. Applications of Logic Gates Computation or Processing – Half Adder – Full Adder Memory – Flip Flop

12. Binary Addition – Two Bits – Tree Bits

13. Half Adder Logic DiagramBoolean ExpressionsTruth Table

14. Full Adder

15. ABC in C out S 00000 10001 01001 11010 00101 10110 01110 11111

16. Full Adder

17. Parallel Adder