2. TODAY YOU ARE LEARNING....... 1. to explain why data is represented in computer systems in binary form 2. to understand and produce simple logic diagrams using the operations NOT, AND and OR 3. to produce a truth table from a given logic diagram.

3. LOGIC GATES

4. SOLVE THESE LOGIC PROBLEMS  http://www.think-logically.co.uk/lt.htm http://www.think-logically.co.uk/lt.htm  Starter - http://www.logic- puzzles.org/game.php?u2=259141ce8e168b457b53b6b9d9a8bceehttp://www.logic- puzzles.org/game.php?u2=259141ce8e168b457b53b6b9d9a8bcee  Starter 2 - http://www.logic- puzzles.org/game.php?u2=a4d4c77ef9e37009fb233bf8f170a395http://www.logic- puzzles.org/game.php?u2=a4d4c77ef9e37009fb233bf8f170a395  Further Reading http://www.ee.surrey.ac.uk/Projects/CAL/digital- logic/gatesfunc/index.html#orgatehttp://www.ee.surrey.ac.uk/Projects/CAL/digital- logic/gatesfunc/index.html#orgate

6. AND GATE Input AInput BOutput (Q) 00 01 10 11 Produces an output only if both inputs are on

7. CAN YOU DRAW A CIRCUIT THAT WOULD ACT LIKE AN AND GATE?

9. OR GATE Produces an output when one or the other input are active…. Input AInput BOutput (Q) 00 01 10 11

10. CAN YOU DRAW A CIRCUIT THAT WOULD ACT LIKE AN OR GATE?

12. NOT GATE A NOT gate inverts its input Input (A)Output (Q) 0 1

13. CAN YOU DRAW A CIRCUIT THAT WOULD ACT LIKE AN NOT GATE?

14. SOME EXTRAS TO FRY YOUR BRAIN

15. NAND IS AN “INVERTED AND GATE”

16. NOT AND = NAND Input AInput B A.B Output (Q)=A.B 00 01 10 11

17. CAN YOU DRAW A CIRCUIT THAT WOULD ACT LIKE AN NAND GATE?

18. A NOR gate is simply an inverted OR gate. Output is high when neither input A nor input B is high:

19. NOT OR =NOR Input AInput B A+B Output (Q) A+B 00 01 10 11

20. CAN YOU DRAW A CIRCUIT THAT WOULD ACT LIKE AN NOR GATE?

21. An XOR gate is constructed similarly to an OR gate, except with an additional NAND gate inserted such that if both inputs are high, the inputs to the final NAND gate will also be high, and the output will be low.

22. XOR – EXCLUSIVE OR Input AInput BOutput (Q) 00 01 10 11

23. CAN YOU DRAW A TRUTH TABLE?

25. NOT GATE

26. AND GATE