1-Bit Half Adder

A half adder takes two, 1-bit inputs and outputs their sum as one, 2-bit value. It is made up of an AND gate and an XOR gate.

Since it has the same number of inputs as outputs, it is easy to create a version using balls. We use a stated XOR to compute the digit in the one's place, and a waiting AND to compute the amount that carries over into the two's place. The A ball goes in and becomes the CARRY, while the B ball becomes the SUM.

This photo of our K'NEX half adder is from the XOR gate side.

The position of the ball represents binary state. Left is 1; right is 0.

A is in the back; B is in the front.

Sum is in the front; Carry is in the back

1 comment:

computer man said...

please can you post instructions on this one? Im very interested in computer type gismoes.