CONTROLLING 8 AIRCRAFT AVIONICS SYSTEM USING

5 SWITCHESSubmitted

ByRedhawan Raziur Rouf

Mohammad Abu NayemZeba Munawara

Shah Mahmud Yasin

CONTENT OBJECTIVE GIVEN PROBLEM CONDITIONS NECESSARY COMPONENTS TRUTH TABLE AND EXPRESSION BASED ON THE

GIVEN CONDITIONS LOGIC DIAGRAM SIMPLIFICATION OF THE DESIGN TRUTH TABLE AND GATE DESIGN OF SN74138 IMPLEMENTED CIRCUIT DIAGRAM RESULT CONCLUSION

OBJECTIVE

To solve the given problem Ensure better design Ensure economical perspective

GIVEN PROBLEM  Suppose in a commercial aircraft there are 8

main avionics system. Each system is switched ON and OFF by its own individual switch. Let for three of the systems, their ON-OFF switch has become unserviceable (faulty).The avionics systems are serviceable and can be operated individually. Design a logic circuit that fulfils the following conditions-

Utilize five systems to operate eight avionics systems individually. However, out of these five, one switch should be “Master ON” switch and one switch should be dedicated as “Master OFF” switch.

CONDITIONS 5 switches are to be used two of the switch should be dedicated for

“Master ON” and “Master OFF” three switches are to control the 8

systems

NECESSARY COMPONENTS

Trainer Board 3 to 8 decoder(74138) Inverter(7404) EX-OR gate(7486) Connecting wires 8 LEDs to represent 8 systems

TRUTH TABLE AND EXPRESSION BASED ON THE GIVEN CONDITIONS

D0, D1 …………D7 are outputs. A, B & C are the switches Expression: D= A’B’C’+ A’B’C+ A’BC’+ A’BC+ AB’C’+

AB’C+ ABC’+ ABC

Inputs Outputs

A B C D0 D1 D2 D3 D4 D5 D6 D7

0 0 0 1 0 0 0 0 0 0 0

0 0 1 0 1 0 0 0 0 0 0

0 1 0 0 0 1 0 0 0 0 0

0 1 1 0 0 0 1 0 0 0 0

1 0 0 0 0 0 0 1 0 0 0

1 0 1 0 0 0 0 0 1 0 0

1 1 0 0 0 0 0 0 0 1 0

1 1 1 0 0 0 0 0 0 0 1

LOGIC DIAGRAM

SIMPLIFICATION OF THE DESIGN

Implementing the earlier logic diagram is complex

Instead we used SN74138, which is a 3 to 8 decoder

The truth table and inside logic diagram for this IC is given.

TRUTH TABLE AND GATE DESIGN OF SN74138

IMPLEMENTED CIRCUIT DIAGRAM

IMAGE OF THE IMPLEMENTED CIRCUIT

RESULT

The system worked perfectly with three switches

The master ON and OFF switches worked perfectly without any malfunction

CONCLUSION

The system worked perfectly. Inverter was used to invert the logic low

output of the 3 to 8 decoder. In real life this circuit can be easily

applied and it will help the pilot to control 8 systems with three switches.