Presentation slide basic information AND + OR + NAND + NOR + EX NOR + Application Other EASA Part66 slide and note can be found here : http://part66.blogspot.com

1. 5.5 LOGIC CIRCUIT

2. LOGIC SYSTEMS
• System performs calculation or makes decisions
• A logical operation on one or more logic inputs
and produces a single logic output to make
decision.
• Using electronic component that can conduct
electricity based on a rule either analog or digital.
• Primarily implement using diodes or transistor
acting as electronic switch

3. POSITIVE AND NEGATIVE LOGIC
• Binary digits are use for the input in logic gate
• Positive logic : Low voltage = 0
High voltage = 1
• Negative logic : Low voltage = 1
High voltage = 0
* Normally use positive logic

4. OR GATE
IF GOT 1 = RESULT MUST BE 1
X A B X
0 0 0
0 1 1
1 0 1
1 1 1
X = A + B

5. AND GATE
IF GOT 0 = RESULT MUST BE 0
A B X
0 0 0
0 1 0
1 0 0
1 1 1
X = A.B

6. NOT GATE
A X
0 1
1 0

7. NAND GATE
A B X
0 0 1
0 1 1
X
1 0 1
1 1 0

8. NOR GATE
A B X
0 0 1
X
0 1 0
1 0 0
1 1 0

9. EXCLUSIVE OR GATE
A B X
0 0 0
0 1 1
1 0 1
X
1 1 0

10. EXCLUSIVE OR GATE
C B A X
0 0 0 0
0 0 1 1
0 1 0 1
X 0 1 1 0
1 0 0 1
Any ODD number of Inputs gives X 1 0 1 0
1 1 0 0
1 1 1 1

11. EXCLUSIVE NOR GATE
A A B X
X
B
0 0 1
0 1 0
X 1 0 0
1 1 1

12. GATE TABLE
EX- NOT
A B OR NOR AND NAND EX-OR
NOR A
0 0 0 1 0 1 0 1 1
0 1 1 0 0 1 1 0 1
1 0 1 0 0 1 1 0 0
1 1 1 0 1 0 0 1 0

13. UNIVERSAL GATE
• NAND gate is universal gate
• It can make another gate
NOT GATE AND GATE
OR GATE
B

14. IC - INTEGRATED CIRCUIT
Quad 2-input AND Gate 7408

15. ADDERS
• An adder or summer is a digital circuit that
performs addition of numbers.
• For new processor, adder are use to calculate
addresses, table indices (database).
• The most common adders operate on binary
numbers

16. HALF ADDER CIRCUIT
• Required 2 input and provide 2 output
• Combination of an exclusive OR and an AND
gate
A B SUM CARRY
0 0 0 0
0 1 1 0
1 0 1 0
1 1 0 1
SUM = A B
CARRY = A . B

17. FULL ADDER CIRCUIT
• Required 3 input provide 2 output
• Combination of 2 half adder and OR gate.
INPUTS OUTPUTS
A B Cin Cout S
0 0 0 0 0
1 0 0 0 1
0 1 0 0 1
1 1 0 1 0
0 0 1 0 1
1 0 1 1 0
0 1 1 1 0
1 1 1 1 1

18. AIRCRAFT LOGIC CIRCUIT
• LANDING GEAR WARNING CIRCUIT

19. AIRCRAFT LOGIC CIRCUIT
• FLIGHT DIRECTOR GYRO FLAG
- drop when gyro system malfunction either
loss of vacuum or electrical signal
Error Flag

20. GYRO FLAG SYSTEM

21. SERVO ALTIMETER OFF FLAG
• Correct operating when sin outputs (‘0’) and the cos
outputs (‘1’).
• When total output is 1, it will energising the OFF Flag
coil, removing the flag from view.