Sequential circuits are a type of electronic circuit where the output depends not only on the current input but also on the history of past inputs. This means that these circuits have memory elements, allowing them to store information and make decisions based on previous states. Common examples include flip-flops, counters, and registers. These circuits are widely used in digital systems, such as computers and microcontrollers, to perform tasks like data storage and processing. They play a crucial role in applications like timing control, signal processing, and communication systems, where the sequence of operations is essential for proper functionality.