Excitation table

In electronics design, an excitation table shows the minimum inputs that are necessary to generate a particular next state when the current state is known. They are similar to truth tables and state tables, but rearrange the data so that the current state and next state are next to each other on the left-hand side of the table, and the inputs needed to make that state change happen are shown on the right side of the table.

Excitation Table For a SR Flip Flop ("X" is "don't care")

Previous State -> Present State	S	R
0 -> 0	0	X
0 -> 1	1	0
1 -> 0	0	1
1 -> 1	X	0

Characteristic equation Q(next) = (S+Q)R' = S+QR'

Excitation Table For a JK Flip Flop ("X" is "don't care")

Previous State -> Present State	J	K
0 -> 0	0	X
0 -> 1	1	X
1 -> 0	X	1
1 -> 1	X	0

Characteristic equation Q(next) = JQ' + K'Q

Excitation Table For a D Flip Flop

Previous State -> Present State	D
0 -> 0	0
0 -> 1	1
1 -> 0	0
1 -> 1	1

Characteristic equation Q(next) = D

Excitation Table For a T Flip Flop

Previous State -> Present State	T
0 -> 0	0
0 -> 1	1
1 -> 0	1
1 -> 1	0

Characteristic equation Q(next) = TQ' + T'Q

References

• umd.edu's explanation - an explanation of excitation tables.
• olemiss.edu's definition
• Types of Flip-flop Behaviour