Later on in the course, flip-flops with better characteristics will be introduced. These are widely available and will be used as sequential elements for the rest of the course. Henceforth, these will be used as building blocks for sequential circuits. In combination logic, truth tables were introduced. These tables do not have the time element stored in the table.
Excitation tables are the analogy of truth tables in the sequential logic arena.
It has a present state and a next state just like what has been seen in previous lectures for RS flip-flops. Of course, the time element is also included in the table. As can be seen, this is almost the same as the RS flip-flop except that for the case when both inputs are T, the output toggles from its current state. Commercial JK flip-flops come in a variety of forms. Using this voltage excitation table, it can be deduced that the LS109 has two mixed-logic use.