NB: Got a bit wordy, highlighted question in red. 1. The problem statement, all variables and given/known data Just a picture of what we're dealing with. I'm given a clock pulse, J and K inputs, and asked to describe the JK master-slave flip flop output. 2. Relevant equations J K Q(t+1) 0 0 Q(t) No change 0 1 0 reset 1 0 1 set 1 1 Q'(t) Complement 3. The attempt at a solution I understand: Clock = 1 -> Master value can be modified by changes to J and/or K Clock = 0 -> Value of Slave is set to that of Master Sorry for the drawing, I hope it is sufficient. During the positive clock phase I called 2, there is a brief blip in the J. J & K are both 1, so I complement the Master value. it is now 1. Now here is where I get uncertain. As I understand it, ANY change in J and/or K, even if there are 1000 changes, during a positive clock phase, will be reflected in the master. So only the FINAL value, once the clock drops from 1 to 0, in the master, "sticks". So I say: that blip in J, well it drops quickly, during a positive clock phase, and so that leaves us with J = 0, K = 1, which is reset, so I drop the Master to 0 again. However, this professor: (skip to 4:10) he's got an image from a book that says: "...something tricky about the master-slave, it's called the "one's catcher", it remembers any activity on the J or K while the clock is high. The J went high, then it went low, but it remembers". It remembers? Can somebody explain how it remembers?