What are sequential logic circuits?

Sequential logic circuits are electronic circuits that use current and past inputs to determine their output state.

Sequential logic circuits are a type of logic circuit where the output is not only determined by the current input but also by the history of the input. This is in contrast to combinational logic circuits, where the output is only a function of the current input. Sequential logic circuits have a 'memory' that stores previous inputs and uses this information to determine the output. This memory is typically implemented using flip-flops, which are circuits that can maintain a binary state indefinitely until changed by an input signal.

The two main types of sequential logic circuits are latches and flip-flops. Latches are level-sensitive, meaning they can change state whenever their input changes, while flip-flops are edge-sensitive, meaning they only change state when a control signal goes from one level to another (for example, from low to high). This makes flip-flops more stable and predictable, and they are therefore used more commonly in digital circuits.

Sequential logic circuits are fundamental to many digital systems. They are used in a wide range of applications, from simple devices like clocks and counters to complex systems like computer memory and processors. For example, a digital clock uses a sequential logic circuit to count the seconds, minutes, and hours, and to display the time in a human-readable format. Similarly, a computer processor uses sequential logic circuits to execute instructions in the correct order and to store intermediate results.

In summary, sequential logic circuits are a key component of digital systems. They provide the 'memory' that allows these systems to perform complex tasks and to operate reliably and predictably. Understanding how sequential logic circuits work is therefore crucial for anyone studying computer science or electronic engineering.