# J-K Flip Flop wave forms

1. Nov 15, 2008

### bec13

I understand that the truth table involved, and how it works, but i don't get the timing of the diagrams. Ive looked on numerous internet sites and through many books but i still don't understand how when J=K=0 and CLK= up, with Q having no change, that the out put (Q) is up, when the others are down. My confusion continues throughout the entire waveform, mostly i believe, as i do not understand the timings of the CLK.

Is there a set time of CLK between each of the inputs? Basically, i would just like a straight answer to explain to me how the waveform works:)

2. Nov 16, 2008

### MATLABdude

http://en.wikipedia.org/wiki/Flip-flop_(electronics)#JK_flip-flop

Note that transitions in the flip-flop state occur only on the rising clock edge, not when the clock is stable. Additionally, the particular case you ask about, J=K=0 with a rising clock edge (and not a HIGH clock) holds the present state of the flip-flop. J=K=1 with a rising clock edge causes the flip-flop state to toggle. Why? That's the defined function of the J-K flip-flop.

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