Logic gates
Task 1 – truth tables!
A truth table is a way of showing what outputs a logic gate can give if it receives certain inputs.
Using logic.ly, connect each of the following logic gates to a switch and a light bulb. Then see what
positions each switch will need to be in to make the light bulb turn on. See the image below for an
example:
What position will the switches
need to be in to make the light bulb
turn on?
TIP: In these
truth tables, a 1
means ON, and a
0 means OFF
Complete the truth tables for each of the following logic gates:
AND
Input A
0
1
0
1
Input B
0
0
1
1
OR
Output
0
0
0
1
Input A
0
1
0
1
Input B
0
0
1
1
NOT
Output
0
1
1
1
Input A
0
1
0
1
Output
1
0
1
0
Extension…
Go on the web to find out three more logic gates, and paste their images below. Then, draw truth
tables out for each of them!
Task 2 – logic diagrams!
For each of the sayings below, construct a diagram in logic.ly, then use the FS Capture Tool to paste
it into the box below:
A bachelor is not married
Create switches for the following input(s)
Create light bulb(s) for the following output(s)
Bachelor?
Married?
Paste your diagram below:
Every good boy deserves fudge
Create switches for the following input(s)
Create light bulb(s) for the following output(s)
Boy?
Been good?
Deserve fudge?
Paste your diagram below:
You can get a credit card if you earn more than £10,000 or you are a home owner
Create switches for the following input(s)
Create light bulb(s) for the following output(s)
Earn more than £10,000?
Home owner?
Get credit card?
Paste your diagram below:
You cannot ride the roller coaster if you are under 4 feet tall unless you are older than 16 years old
Create switches for the following input(s)
Create light bulb(s) for the following output(s)
Under 4 feet tall?
Older than 16?
Ride roller coaster?
Paste your diagram below:
To get a passport, you must be 16 or older, and a UK resident
Create switches for the following input(s)
Create light bulb(s) for the following output(s)
16 or older?
UK resident?
Get a passport?
Paste your diagram below:
You can have an ice cream if you are by the beach AND it is sunny
Create switches for the following input(s)
Create light bulb(s) for the following output(s)
By the beach?
Sunny?
Can have an ice cream?
Paste your diagram below:
You can watch TV if it is NOT a weekday, AND it’s before 9pm
Create switches for the following input(s)
Create light bulb(s) for the following output(s)
Weekday?
Before 9pm?
Watch TV?
Paste your diagram below:
Extension
Create the following circuit in logic.ly:
Toggle switches
Seven-segment display
The seven segment display has 4 inputs, but can use all 16 combinations of their on/off positions to
output the following characters:
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, b, C, d, E, F
In the tables below, write down the combination of 1s and 0s required to display each character:
0
A
0
B
0
1
C
0
D
0
A
1
B
0
5
A
1
B
0
C
1
B
1
D
0
B
1
D
0
A
0
B
1
A
0
B
1
C
0
D
1
C
1
D
1
A
1
B
1
3
C
0
D
0
A
1
B
1
7
C
1
D
0
A
1
B
1
b
F
A
1
C
0
6
A
A
0
2
D
1
A
0
B
0
C
0
D
0
A
0
B
0
8
C
1
D
0
A
0
B
0
C
C
0
4
D
0
A
1
B
0
D
0
C
0
D
1
C
1
D
1
9
C
0
D
1
A
1
B
0
d
C
1
C
1
E
C
1
D
1
A
0
B
1