1. Logic Gates How Boolean logic is implemented

2. Transistors used as switches to implement Boolean logic: ANDOR Logic with Transistors

3. Logic Gates Digital electronics : design of binary systems Gates are basic building block: – One for each of 6 Boolean logic rules at tip means NOT

4. Not Plus one additional gate NOT gate reverses a signal InputOutput 01 10

5. Combinations Output of one gate can serve as the input to the next gate Use to produce new logic: – Ex: Two ANDs used to make a 3 input AND Interactive Interactive

6. Combinations Can also create basic gates from other ones Ex: AND fed into NOT same as NAND

7. NOR and NAND gates are universal – Can be used to make any other gate Ex: AND made with NORs: Interactive Universal Gates

8. NOR gates can be single transistor – Electrically simple to design – Apollo’s mission computer was built exclusively from NOR gates NOR Universal Gates

9. Useful Circuits: Simple Memory Decoder HalfAdder

10. Building A Truth Table Inputs are always the same (need every combo) – You figure out outputs: More inputs = more combinations 3inputs = 8 rows 4 inputs = 16 rows etc… Input0Input1Output0 00? 01? 10? 11?

11. Using the Circuit Simulator Always start with DC power Use Toggles as inputs – Click name below components to rename Use LEDs as outputs Wire by dragging from one connector dot to another

12. OffOn Using the Circuit Simulator Red connector dots have power, black do not – Top input has power at output – Bottom input is not letting power through Toggle switches are “On” when light part is at bottom: