Project 1 Adder/Subtractor

The Adder/ Subtractor is a circuit which uses a 4-bit fuller adder chip and an XOR chip to add or subtract two 4-bit binary numbers. A slide switch is used to switch between an Adder and a Subtractor. This works by connecting the second number and the slide switch to an XOR gate. When the slide switch is switched to High, the XOR gate changes the sign of the second number so that the circuit functions as a subtractor. The LEDs represent the number in binary; the leftmost LED is the MSB, and the rightmost LED is the LSB.