Explanation of edges, circuit logic and use of flip flops

help me

hello i got stucked in several questions related to flip-flop and shift register, i hope there is someone who can answer these:

1.What is positive edge and negative edge?
2. What are the differences between sequential circuit and combinational circuit?
3.What are the applications of flip-flop

thank

Re: help me

Ok junior
1) edges .. edges of signals are important in edge triggered devices .. which now are the standard . it means that an edge trigguered device will change its status at the transition moment . from 0 to 1 for positive edge devices and from 1 to 0 for negative devices .. This arrangement is the best .because the device or flip flop will remain stable when there are no transitions ..
2) combinational and sequential logic ,,is logic that we are talking about . are two different types of logic .one changes the output immediatly and it only dependends on how fast the electrons can move from the input .. that's combinatorial .. there is no notion of clock .. The other logic has a synchronizing signal called the clock ..
and the outputs only change when the clock says it to do so. This is much more stable because with the combinatorial logic you have electron "races" between wires whoever arrives first will change the output .. you don't want that .
So you use sequential logic with a clock .This allows the signals to propagate at the output .. and then the clock gives the GREEN light to the new output.
3) applications of flip flops ..
counters , state machines .. registers ..

Re: help me

these are the elementary questions you are dealing with so i would suggest that go for some basic digital hand book to get the answers or just get hold of the neighbour who has done or is pursuing btech or any technical course in electronics