Digital Circuits for High School Students

Part 2 Work Sheet
Prepared by Charles S. Tritt, Ph.D.
July 18, 1997

4-bit Comparator

Note: B = 01012 = 510				Outputs
Inputs (A)				Expected			Observed
A3	A2	A1	A0	A > B	A = B	A < B	A > B	A = B	A < B
0	0	0	0	0	0	1
0	0	0	1	0
0	0	1	0	0
0	0	1	1	0
0	1	0	0	0
0	1	0	1	0
0	1	1	0	1
0	1	1	1	1
1	0	0	0	1
1	0	0	1	1
1	0	1	0	1
1	0	1	1	1
1	1	0	0	1
1	1	0	1	1
1	1	1	0	1
1	1	1	1	1

Comments:

4-bit Adder

Note: B = 01012 = 510				Outputs
Inputs (A)				Expected	Observed
A4	A3	A2	A1	(Base 10)	C4	Sigma4	Sigma3	Sigma2	Sigma1
0	0	0	0	5
0	0	0	1	6
0	0	1	0	7
0	0	1	1	8
0	1	0	0	9
0	1	0	1	10
0	1	1	0	11
0	1	1	1	12
1	0	0	0	13
1	0	0	1	14
1	0	1	0	15
1	0	1	1	16
1	1	0	0	17
1	1	0	1	18
1	1	1	0	19
1	1	1	1	20

Comments: