Homework Ciruits 2 Due April 24, 2008
Majority circuit
This homework, when submitted, must be accompanied by its grading
sheet.
Use Logg-o to construct a majority circuit. Here
is the scenario:
We have three voters, A, B and C, voting on an issue which will either
pass or fail. We wish to construct a circuit that will model this
scenario, as follows:
-
the circuit will have three input switches, A, B, and C, and one
output
light
-
a "yes" for voter A will be realized in our circuit by input switch A being
on;
a "no" is off
-
similarly for B and C
-
passage of a measure will be signalled by the output light being
on,
failure
by
off
A majority circuit is defined as follows:
-
the output light should be on if two or more of the inputs is on
-
otherwise, the light should be off
-
in words,
-
if (A =on
and
B =on)
or (A =onand
C =on)
or (B =on and
C =on)
-
then the light should be on
-
otherwise, the light should be off
Your circuit diagram will look like the following:
Inputs:
Gates:
Output:
A (switch on or off) ----------------->
B (switch on or off)
----------------->
(you fill
in)
-----------------> pass (light on) or
fail (light off)
C (switch on or off) ----------------->
Do this:
-
use Logg-o to wire together the inputs to some gates and the output
so as to provide the required output
Hint: think about the logical specification given in red
above.
-
Again, you will need to do this on a PC, in order to save your Logg-o
file (doesn't work on Mac)
-
test your circuit as follows:
-
try all 8 combinations of inputs: off off off, off off on,
etc.
-
those inputs that consist of 2 or 3 on's should turn the light on
-
all others should turn the light off
-
print out your circuit -- just page 1 of the Logg-o Web page.
Do file..print to select page 1 only. If the circuit does
not print, see the directions for what
to do.
-
include a logic table (like the one in HW 7.1). You can just hand-write
this somewhere on the printout.
-
write your name on your printout
Submit: your printout