PHYS345 Electricity and Electronics

Hint for 13-35

First make a circuit that adds one bit from the number A and a corresponding bit from number B. After the circuit module for adding corresponding bits is available, an adder for four bits may be assembled from four such single-bit adder modules.

Don't forget that a carry bit input, name it Ci should be included to incorporate overflow from the preceding addition of lower-significance bits.

Also note that you will need two output bits, one for the sum bit S and the other for the carry bit output Co.

Last updated Nov. 8, 1999.
Copyright George Watson, Univ. of Delaware, 1999.