J-K CLOCKED FLIP-FLOP

The J-K flip-flop shown is made up of NAND gates. It has two extra NAND gates to CLOCK the flip-flop. The CLOCK tells the flip-flop when to pay attention to its inputs and when to ignore them.

Flip-flops store a BIT of information. In a computer some calculations and processes take longer than others. This means that flip-flops must wait until everything has caught up before they can work out their output.

J	K	QN+1	____ QN+1
0	0	QN	__ QN
1	0	1	0
0	1	0	1
1	1	__ QN	QN

 

 

 

 

 

 

 

        

 

Memory means that the flip flop remembers its output. When J and K are 0, Q can be 1 or 0 depending on its value before J and K became 0. When J and K are 1, Q can be 1 or 0 depending on its value before J and K became 0. Q will be the opposite of what it was. This is the meaning of the bar across the top of the Q.

_                                            _                           _

Q means NOT Q. If Q is 1 the Q is 0. If Q is 0 the Q is 1.

 

If C is 0 then the output of the first two NANDs is high(1) and the flip flop remains in memory state.

Show the output on the diagram when C is 1, J is 1 and K is 0.