2. Figure shows four switches that are part of the control circuitry in a copy machine.

The switches are at various points along the path of the copy paper as the paper

passes through the machine. Each switch is normally open, and as the paper passes

over a switch, the switch closes. It is impossible for switches SW1 and SW4 to be

closed at the same time. Design the logic circuit to produce a HIGH output

whenever two or more switches are closed at the same time. Use K mapping and

take advantage of the don't-care conditions.

SW1

SW2

SW3

SW4

41

w

+5V

+5V

+5V

+5V

Logic

circuit

X

HIGH whenever

two or more switches

are closed*

*SW1 and SW4 will never

be closed at the same time