Unit V: Sequential Logic Circuit | BCA 1st Semester Digital Logic System Notes Pdf

Sequential Logic circuits have some type of intrinsic "Memory" built in, in contrast to Combinational Logic circuits, which change state depending on the actual signals being supplied to their inputs at that moment. This indicates that a type of "before" and "after" effect is associated with sequential circuits, allowing them to take into consideration both their past input state and those that are actually present. In other words, the "present input," "past input," and/or "past output" states are functions of the "output state" of a "sequential logic circuit." Sequential logic circuits have "Memory" because they retain these conditions and remain in their present state until the next clock signal modifies one of the states.

Sequential logic circuits are often referred to as two-state or bistable devices because they can have their outputs set to either logic level "1" or "0," and they will stay "latched" (hence the name latch) in this state or condition indefinitely until another input trigger pulse or signal is applied, which will cause the bistable to change its state once more. The word "Sequential" refers to events occurring in a "sequence," one after another. In circuits using sequential logic, the timing of events is determined by the real clock signal. Simple sequential logic circuits can be created by simply connecting together widely available NAND gates and/or NOR gates in a specific combination to create the necessary sequential circuit. Standard Bistable circuits like Flip-flops, Latches, and Counters are examples of simple sequential logic circuits that can be created in this way.

In this “Sequential Logic Circuit - Digital Logic System” you will learn about the following topics:

1. Introduction to sequential logic circuit
2. Flip-Flops:
3. RS flip flop, D-flip flop, J-K flip flop, T flip-flop, Triggering of flip flops (Positive, negative and level trigger), Master-Slave flip-flop
4. Analysis of clocked sequential
5. Circuits with example
6. State table
7. State diagram
8. State Equation
9. Flip-flop input functions
10. State reduction and assignment
11. Flip-Flips excitation Tables and design procedures

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The article Sequential Logic Circuit - Digital Logic System is contributed by Aakrity Chapagai, a student of LA GRANDEE International College.

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