Question

has any done this ? Draw the truth table showing the dependency Q (T+1) of Q(t) for the JK flip-flop. Include the logic diagram, and the truth table for the D flipflop, on which the construction of the JK flip-flop depends.

Answer 1

JK Flip Flop Truth Table:

A J,K Flip Flop has 2 input J and K (along with clock) and two outputs Q and Q'. The truth table looks like this:

Clock	J	K	Present State (Q(t)		Next State (Q(t+1))
			Q	Q'	Q	Q'
1	0	0	0	1	0	1
1	0	0	1	0	1	0
1	0	1	0	1	0	1
1	0	1	1	0	0	1
1	1	0	0	1	1	0
1	1	0	1	0	1	0
1	1	1	0	1	1	0
1	1	1	1	0	0	1

Logic diagram for D flip flop:

It is made up of 4 Nand gates. The output is dependent on the previous state.

The truth table for D flip flop:

Clock	D	Present State (Q(t)		Next State (Q(t+1))
		Q	Q'	Q	Q'
0	0	0	1	0	1
0	0	1	0	1	0
0	1	0	1	0	1
0	1	1	0	1	0
1	0	0	1	0	1
1	0	1	0	1	0
1	1	0	1	1	0
1	1	1	0	1	0

No change occurs when clock is 0 regardless of the value of D.

The change happens only for value of D=1,Clock=1.