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2
Lab #2 Activity
Build the given circuit used to display numbers using a 7-segment display.
The schematics on the following pages show the circuit using a common anode
(CA) 7-segment display (M72) using the 74LS47 BCD to 7-segment active low
decoder and the common cathode (CC) 7-segment display (M74) with the 74LS48
BCD to 7-segment active high decoder.
1) Select one of the designs (CA or CC) □ CA
□ CC
2) Use the necessary datasheets
3) Show your instructor a schematic of your design (complete schematic showing
all the signals, name of signals, and pin numbers).
4) Simulate the circuit and show instructor the simulation result.
5) Build the circuit and show your instructor the working circuit.
Do not take
the circuit apart
as it is used in
lab activity #3!
3
Lab #2 Activity
a
A0
A1
A2
A3
(A0  A3 signals are generated
by using 4 Switches located on the
digital module card)
74LS47
BCD
To
7-seg
Decoder
active
Low
outputs
+5v
R 470Ω
g
CA 7-segment
display
Common Anode 7-segment display design
4
Lab #2 Activity
a
A0
A1
A2
A3
(A0  A3 signals are generated
by using 4 Switches located on the
digital module card)
74LS48
BCD
To
7-seg
Decoder
active
High
outputs
Ground
R 470Ω
g
CC 7-segment
display
Common Cathode 7-segment display design
5
Lab #2 Activity
6
Lab #2 Activity
74LS47 Connection Data
74LS47
7
Lab #2 Activity
74LS47 Truth Table
8
Lab #2 Activity
Common Anode: M72
9
Lab #2 Activity
Common Cathode: M74
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11
Lab #3 Activity
Build a circuit that will add two 4-bit binary numbers (A0A3 and B0 B3).
Use the 74LS83 full adder chip to perform this 4-bit addition.
Display the sum value using the common anode 7-segment display or the common
cathode display (M74 C/D) built in lab activity #2. As well, display the carry bit.
A block diagram of this circuit is shown on the next two pages.
1) Show your instructor a schematic of your design (complete schematic showing
all the signals, name of signals, and pin numbers).
4) Simulate the circuit and show instructor the simulation result.
5) Build the circuit and show your instructor the working circuit.
Do not take
the circuit apart
as it is used in
lab activity #4!
12
Lab #3 Activity
A D
S 0  S3
74ls83 4-bit
Full Adder
ag
Cin
GND
Cout
A3 A2 A1A0 B3 B2 B1 B0
Carry bit LED
Switches
(Digital Module)
BCD
To
7-seg
decoder
CA 7-segment
display
74LS47
R 470 Ohms
+5 v
Common Anode 7-segment display design
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Lab #3 Activity
A D
S 0  S3
74ls83 4-bit
Full Adder
ag
Cin
GND
Cout
A3 A2 A1A0 B3 B2 B1 B0
Carry bit LED
Switches
(Digital Module)
BCD
To
7-seg
decoder
CC 7-segment
display
74LS48
R 470 Ohms
Gnd
Common Cathode 7-segment display design
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Lab #4 Activity
Build a circuit that will add and subtract two 4-bit binary numbers (A0A3 and B0
B3). Use the 74LS83 full adder circuit, (used in lab activity #3), and add XOR
gates to perform the 4-bit addition & subtraction.
Display the sum value using the common anode 7-segment display or the common
cathode display (M74 C/D) used in lab activity #3.
A block diagram of this circuit is shown on the next two pages.
1) Show your instructor a schematic of your design (complete schematic showing
all the signals, name of signals, and pin numbers).
4) Simulate the circuit and show instructor the simulation result.
5) Build the circuit and show your instructor the working circuit.
Do not take
the circuit apart
as it is used in
lab activity #5!
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Lab #4 Activity
2’s Complement Adder &Subtract circuit
To 7-segment display circuit
from lab activity #3
74ls86
Carry bit LED
1717
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Lab #5 Activity
Build a circuit that will compare two 4-bit binary numbers (A0A3 and B0 B3).
Use the 74LS85 comparator chip to perform this 4-bit comparison.
Display, using three LEDs, whether A = B, A > B or A < B.
Use the adder circuit and the common anode 7-segment display or the common
cathode display (M74 C/D) used in lab activity #4.
A block diagram of this circuit is shown on the next two pages.
1) Show your instructor a schematic of your design (complete schematic showing
all the signals, name of signals, and pin numbers).
4) Simulate the circuit and show instructor the simulation result.
5) Build the circuit and show your instructor the working circuit.
19
Lab #5 Activity
A D
S0  S3
Cin
74ls83 4-bit
Full Adder Cout
+
─
BCD
To
7-seg
decoder
ag
CA 7-segment
display
74LS47
LED
R 470 Ohms
Common Anode 7-segment display design
74ls85 4-bit
Comparator
74ls86
A3 A2 A1A0
B3 B2 B1 B0
Switches
(Digital Module)
+5v
A<B
A>B
A=B
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Lab #5 Activity
A D
S0  S3
Cin
74ls83 4-bit
Full Adder Cout
GND
BCD
To
7-seg
decoder
ag
CC 7-segment
display
74LS48
R 470 Ohms
Common Cathode 7-segment display design
74ls85 4-bit
Comparator
74ls86
A3 A2 A1A0
B3 B2 B1 B0 Carry bit LED
Switches
(Digital Module)
Gnd
A<B
A>B
A=B
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