# Logic Systems Boolean Reduction Question !

1. Dec 12, 2004

### DethRose

Logic Systems Boolean Reduction Question!!!!!!!!!!!!!!!!!!!!!

Ok i recieved an assignment due on monday and have to idea how to get started...i am supposed to design a traffic light using the following criteria:

a) The east west (E-W) traffic light will be green whenever both lanes C and D are occupied.
b) The E-W light will be green whenever either C or D is occupied but lanes A and B are not
both occupied.
c) The north -south (N-S) light will be green whenever both lanes A and B are occupied but
C and D are not both occupied.
d) The N-S light will also be green when either A or B is occupied while C and D are both
vacant.
e) The E-W light will also be green when no vehicles are present.

Using the sensor outputs A, B, C and D as inputs, design a logic circuit to control the traffic
light. There should be two outputs, N-S and E-W, that go HIGH when the corresponding
light is green. Simplify the circuit as much as possible and show all steps!

I need to write an equation for each light set (e-w) and (n-s) but have no idea what they are. I think they may be:

N-S

$$(ab)$$$$($$$$\overline c + \overline d$$$$)$$$$+$$$$(a+b)$$$$($$$$\overline c \overline d)$$

E-W

$$(cd)+(c+d)(\overline a$$$$+$$$$\overline b)$$$$+ \overline a$$$$\overline b$$$$\overline c$$$$\overline d$$