Drexel University
Electrical and Computer Engineering Department
ECE 200 – Intelligent Systems
Spring 2004
Lab 2. Combinational Circuit Design
Dinesh Obalappa and ECE-200 Staff
Introduction:
In this lab, you will use the Pencilbox Logic Designer to design, build and test a
Combinational Logic Circuit. You will apply the techniques you have already learned for
designing logic circuits.
Objective:
a) Become familiar with the Pencilbox Logic Designer, the integrated circuit (IC)
chips and building a digital circuit on a breadboard.
b) Design a combinational logic circuit involving three inputs.
c) Build and test the combinational logic circuit using the Pencilbox Logic Designer.
Procedure:
Read all of the information about the Pencilbox, the Integrated Circuits, the Bread
boarding instructions and the Control Panel from MiniLab1 manual and make sure you
have familiarized yourself with the Pencilbox Logic Designer. Pay careful attention to
the layout of the pins on the IC chips, the connectors on the Control Panel, use of the
light emitting diodes (LED’s), etc.
Read this instruction sheet completely and make sure you understand the goal of this
MiniLab. Before building your circuit in the Lab, complete the Prelab form at the end of
this manual, get it signed by the Lab Assistant in Room 7-205 and turn it in with the Lab
Report for this experiment.
You are given the following “mystery sigma” which defines a logic function F of three
variables X, Y, and Z. Your goal is to design, build and test a combinational logic circuit
which implements the function.
F(X, Y, Z) = ∑(X, Y, Z)(3, 4, 6, 7)
Remember that NAND gates and NOR gates are the universal gates since any digital
system can be implemented with these gates alone. So make sure your design has only
NAND gates or only NOR gates, and not a combination of the two. Extra points will be
given for use of fewer gates/chips. Make sure to test every chip before building a circuit.
The report for this lab is to follow the same format as that for the first lab.
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Drexel University
Electrical and Computer Engineering Department
ECE 200 – Intelligent Systems
Spring 2004
Prelab
Name:________________________________________________________
Read the instructions in the previous sections of this manual and also the previous
manual. Pay careful attention to the layout of the pins on the IC chips, the connectors on
the Control Panel, use of the light emitting diodes (LED’s), etc. Complete this form, get
it signed by the Lab Assistant in Room 7-205 and turn it in with the Lab Report.
1)
2)
3)
4)
5)
6)
7)
List the minterms of F _____________________________________________
List the maxterms of F _____________________________________________
List the minterms of F ____________________________________________
What kind of gates does a 7400 IC chip have? How many?_____________
What kind of gates does a 7402 IC chip have? How many?_____________
How many pins do each of the above IC chips have?__________________
In each of the above IC chip, which pin is Vcc?
Which pin is
Ground?____________________
State DeMorgan’s theorem for three variables:
8)
_______________________________ ______________________________
9)
Draw the implementation of OR and AND functions using NAND gates:
OR
_____________________________
10)
AND
________________________________
Draw the implementation of OR and AND functions using NOR gates:
OR
_____________________________
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AND
________________________________
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Drexel University
Electrical and Computer Engineering Department
ECE 200 – Intelligent Systems
11)
12)
2/12/2016
Spring 2004
Design the Mystery Logic circuit which implements F using only NAND gates
or only NOR gates. Draw the logic diagram (using gate symbols) for your
implementation.
Draw the circuit diagram (using ICs) for your implementation. Label all the
Vcc, Ground, Input & Output pins and show the interconnections.
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