digital report botak

8/7/2019 DIGITAL REPORT BOTAK

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DIGITAL REPORT EED 2303

MOHD NURUL IZWAN BIN MOHAMAD EEE 10910 Page 1

OBJECTIVES

y To investigate the behaviors of all the logic gates involved in the lab experiment.y To make comparisons between the input and output between different logic gates.y To enhance students in becoming a little bit more experts in constructing digital

electronic circuits.

y To explore the output of a combination of more than one logic gate in a circuit.y To ensure that the students have all the skills and adequate knowledge regarding

logic gates.

y To ensure that students can analyze the truth table of the logic gates used in thecircuits manually or theoretically.

y To compare the results of the logic gates circuits theoretically and practically.y To indentify the reasons to the problems of where the output of the logic gates

circuits does not match theoretically and practically sometimes.

y To ensure that students can describe the operation of logic gates well.y To ensure that the students can analyze Boolean algebra well.y To ensure that the student can design combinational logic circuits well.


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INTRODUCTIONOF LOGIC

GATE

A logic gate is a combination of different electronic components, which takes one or more logic-

level inputs and produces a single logic-level output. Presently, nowadays many electrical

appliances are found to be able to receive commands for carrying out their specific tasks.

The appliances takes in information from environment, make a decision on the

information and then give out the result as an output. An electronic device that can be

used to perform this operation is called as logic gates.

In logic gate, there may be one or more inputs however there can only be one output for

one logic gates, unless in a circuit there are more than one logic gate combined together

to produce more than one output. The inputs and outputs of this logic gates are mainly

consisting of the digit 1 and 0 only. It is only when the inputs or outputs are at

HIGH condition it is considered as 1 and when in LOW condition, it is considered as

logic 0.

There are several classes of significant logic gates. Namely they are the AND GATE,

OR GATE, NOT GATE, NAND GATE, NOR GATE, X-OR GATE and X-

NOR GATE. These different gates bring different outputs from one another when the

same inputs is inserted or applied. In other words, different gates bring different

characteristics.


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Explanations practical test for task 6

Question task 6

a chemical plant needs a microprocessor-driven alarm system to warn a critical condition

on one of its chemical tanks. The tanks have four HIGH/LOW (1/0) switches that

monitor temperature (T), pressure(P), fluid level(L), and weight(W). design a system that

notifies the microprocessor to activate an alarm when any of the following conditions

arise

i. High fluid level with high temperature and high pressureii. Low fluid system with high temperature and high weight

iii. Low fluid level with low weight and height temperatureiv. High fluid level with low weight and high temperature

Explanations task 6

Task 6 is a question that needs us to design our own truth table and circuits based on the

conditions that has been provided to us as stated in the job sheet. After finish doing the

truth table, a Boolean expression is needed to be written from the truth table so that logic

gates construction can be designed from the expression. Finally, simulate the logic gates

construction in multisim to test its validity whether the output obtained from the multisim

circuit is as the same as the theory made earlier. Thus, the result is compared and the

result is valid as it is the same practically and theoretically. The results can be observed at

the job sheet given.


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Task 6

In this task I design this circuit used AND gate (7408), OR gate (7432), NOT gate

(7404), LED and switch. This circuit has 4 inputs that are T (temperature), P (pressure), L

(fluid level) and W (weight). The LED is to present the output of this circuit. To check

the answer refers to truth table.

TRUTH TABLE

INPUT OUTPUT

T P L W X

0 0 0 0 0

0 0 0 1 0

0 0 1 0 00 0 1 1 0

0 1 0 0 0

0 1 0 1 0

0 1 1 0 0

0 1 1 1 0

1 0 0 0 1

1 0 0 1 1

1 0 1 0 1

1 0 1 1 0

1 1 0 0 1

1 1 0 1 1

1 1 1 0 1

1 1 1 1 1

KARNAUGH MAP

TP/LW 00 01 11 10

00

01

11 I I I I

10 I I I

EXPRESSION FROM K.MAP = TP + TL + TLW


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CIRCUIT DESIGN BASED FROM EXPRESSION, TP + TL + TLW.

When L= 1 T=1 P= 1 W= X OUTPUT= 1

When L= 0 T=1 P= x W=1 OUTPUT= 1


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Explanations practical test for task 7

Question task 7

Design a combinational circuit that uses only NAND gates to implement a security

system for a TEXAS factory. The circuit has two inputs A (that is high when the

system is armed, low else) and D (that is high when the door is open, low else) and two

output G (green LED) and R (red LED). The circuit will operate as follows:

i. When the door is closed and the system is armed the green LED will beilluminated and the red LED will not be illuminated.

ii. When the door is open and the system is armed the red LED will be illuminatedand the green LED will not be illuminated.

iii. When the system is not armed, both red and green LED will be illuminated.

Explanations task 7

Task 7 needs me to design a combinational circuit that uses only NAND gates to

implement a security system for a factory. This task needs me to design and create the

circuit of logic gates based on the question that given on the job sheet. After that, a truth

table is written in theoretically. From the Boolean expression, construct the logic circuit.

This circuit is then simulated in multisim to test its validity. Lastly, the result that

obtained from multisim is valid as the theory results.


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Task 7

In task 7, I design this circuit used OR gate (7432), NOT gate (7404) as a combinational

gates for NAND gates, LED and switch. This circuit has 2 inputs that are inputs A (that

is high when the system is armed, low else) and D (that is high when the door is open,

low else). The LED is to present the output of this circuit. To check the answer refers to

truth table.

TRUTH TABLE

INPUT OUTPUT

D A G R

0 0 1 1

0 1 1 0

1 0 1 1

1 1 0 1

KARNAUGH MAP

A / D 0 1

0 1 1

1 1 0

G = A + D R= A + D

EXPREESION FROM KARNAUGH MAP, G = A + D, R= A + D

A / D 0 1

0 1 0

1 1 1


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CIRCUIT DESIGN BASED FROM EXPRESSION, G = A + D, R= A + D

When A = 0 D = 0 OUTPUT R=1 G=1



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CONLUSION

When I finish this assessment lab, I learn how to produce a logic gate using switch,

resistance and LED to determine the output. In this job sheet, I also learn about how to

describe the logic operation for logic that has 2 inputs and 3 input. The other thing that I

learn in this practical test that is how to design the circuit and how to understand the

operation of logic circuit by using the formula that we have learn in class before do the

practical test. To analysis the problem I have do using Boolean algebra to answer the

question and to find the problem at the circuit. I also learn a little why the circuit

sometime not fully functions. This happen because a problem by using the older project

board or the another equipment was broken. This assessment is good because it can give

the student very skillful after finish the practical. As in conclusion, this practical test and

lab assignment is to test the credibility and creativity of the students to describe the

characteristics of various logic gates and how to identify them. Apart from that, students

must also know how to analyze Boolean algebra and how to design combinational logic

circuits. By doing this assessment, all those criteria has been satisfied, however, there are

some circuits that the outputs are quite different from theory. This might due to some

reasons such as the flaw and slack of the project board and also the condition of the

electronic components used. Nevertheless, a comparison of the theory result and also the

practical is needed to be recorded so that the flaws of the practical circuit can be detected.


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REFERENCE

BOOK:

y Digital electronic (third edition) prentice hally Digital system (sixth edition) tocci prentice hally Longman Essential Physics SPM book by Yap Eng Keat and Khoo Goh Kowy Digital Fundamentals fifth book by Floyd

WEBSITE:

y www.wikipedia.comy http://www.geocities.com/templarser/gates.htmly http://www.technologystudent.com/elec1/dig3.htm


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