Hey Everyone, I am just starting now to REALLY get into digital circuits and I am trying my hardest to learn about Flip Flops via the internet. What I am finding is a horrible amount of inconsistencies and it is confusing me! First I started here.. http://computer.howstuffworks.com/boolean4.htm One inconsistency I found is that he says r=1 and s=1 is not allowed and r=0, s=0 remembers, but EVERYWHERE else I read it says the opposite! Then I moved on to the JK flip flops. (same article) I quickly realized that this article does NOT use the standard symbol for the JK flip flop. I am trying to match together all these inconsistencies. So this is what I understand.. In a normal JK flip flop symbol.. S(or the top pin) means "Preset" which I am unsure of what that exactly means. R(or the bottom pin) means "Clear" And the triangle symbol means clock. J and K are the parameters used to control the output Q and Q'. I also noticed that the truth tables from different sources were different. Why is it that some of the tables don't include "Preset" or "Clear"?? The table from "How stuff works" includes the clock signal, but the table from wiki does not it has a "comment" and a "Qnext" which I do not know what that means. http://en.wikipedia.org/wiki/Flip-flop_(electronics)#JK_flip-flop Then I tried opening a circuit simulator any messing around with the JK flip flop and I couldn't replicate ANY of the things it talks about in the "How stuff works" article. I also tried looking to other sources but I haven't had too much time yet to go through these sources in detail. If anyone can help me out and clear some of this up it would be most appreciated!