1. Flip Flop

2. What is a Flip Flop? Flip-Flops
"Flip-flop" is the common name given to two-state devices which offer basic memory for sequential logic operations.
Flip-flops are heavily used for digital data storage and transfer and are commonly used in banks called "registers" for the storage of binary numerical data.

3. Sequential Logic
In digital circuit theory, sequential logic is a type of logic circuit whose output depends not only on the present value of its input signals but on the past history of its inputs. This is in contrast to combinational logic, whose output is a function of only the present input. That is, sequential logic has state (memory) while combinational logic does not. Or, in other words, sequential logic is combinational logic with memory.

4. Sequential Logic

5. Flip Flops
The memory elements in a sequential circuit are called flip-flops. A flip-flop circuit has two outputs, one for the normal value and one for the complement value of the stored bit. Binary information can enter a flip-flop in a variety of ways and gives rise to different types of flip-flops.

6. Flip Flop Chip

7. Flip Flop Circuit

8. Types Of Flip Flops

9. How To Construct Flip Flop?
A flip-flop circuit can be constructed from two NAND gates or two NOR gates.

10. SR Flip Flop (latch)
Each flip-flop has two outputs, Q and Q', and two inputs, set and reset. When Q=1 and Q'=0, it is in the set state (or 1-state). When Q=0 and Q'=1, it is in the clear state (or 0-state)

11. Basic flip-flop circuit with NOR gates

12. Basic flip-flop circuit with NAND gates

13. D Flip-Flop
The D input goes directly into the S input and the complement of the D input goes to the R input. The D input is sampled during the occurrence of a clock pulse. If it is 1, the flip-flop is switched to the set state (unless it was already set). If it is 0, the flip-flop switches to the clear state.

14. D FLIP FLOP

15. JK FLIP FLOPS
Inputs J and K behave like inputs S and R to set and clear the flip-flop (note that in a JK flip-flop, the letter J is for set and the letter K is for clear). When logic 1 inputs are applied to both J and K simultaneously, the flip-flop switches to its complement state, ie., if Q=1, it switches to Q=0 and vice versa.

16. JK FLIP FLOPS

17. T FLIP FLOP
The T flip-flop is a single input version of the JK flip-flop.the T flip-flop is obtained from the JK type if both inputs are tied together. The output of the T flip-flop "toggles" with each clock pulse.

18. T FLIP FLOP

19. Triggering of Flip-flops
The state of a flip-flop is changed by a momentary change in the input signal. This change is called a trigger and the transition it causes is said to trigger the flip-flop.

20. Triggering of Flip-flops
The clock pulse goes through two signal transitions: from 0 to 1 and the return from 1 to 0. As shown in Figure 8 the positive transition is defined as the positive edge and the negative transition as the negative edge.