Homework problem: Complete the table for the following sequential circuit.

Thread Starter

Gonzalo Armbrust

Joined Jun 28, 2015
I have to construct a truth table based on the sequential circuit that is given, however i'm incredibly lost as to where to start. ( I have attached a picture of the problem below)

For these types of problems, am I able to start at any input?For example according to the problem, lets say that A=0, B=0, and =1, if I know that B is set to zero, which then gets negated by the NOT gate to 1, and combined with X ( which equals 1), then the output of the logic gate is 1 ( since the output of the gate negated is 1), does this make the next state of A = 1, and also B = 1, since it would still be 1 through the D circuit?


to find the next state value of B, could I just start at A input, and deduce it would be the same value of what A is initially since they are only seperated by a D circuit?

My biggest question for these types of questions is, what input do I start exactly?



Joined Mar 31, 2012
No need for 1.1 MB files when <22KB will do quite nicely.


Yes, your truth table is correct.

Notice that an XNOR gate with one input negated IS an XOR gate.