Published by: Nuru
Published date: 22 Jun 2021
There are two types of sequential circuits. They are synchronous which is clocked and asynchronous which is unclocked.
Output at any instant of time depends not only on the present inputs but also on past/previous outputs.
Consists of a combinational circuit to which memory elements are connected to form a feedback path. Memory elements are devices capable of storing binary information within them. The binary information stored in the memory elements at any given time defines the state of the sequential circuit. Introduction to the sequential circuit deals with a brief knowledge of sequential circuits.
Types of sequential circuits:
A system whose behavior depends upon the order in which its input signals change and can be affected at any instant of time.
The memory elements commonly used in asynchronous sequential circuits are time-delay devices.
A system whose behavior can be defined from the knowledge of its signals at discrete instants of time.
Synchronous sequential circuits that use clock pulses in the inputs of memory elements are called clocked sequential circuits.
Memory Devices:
Latches A latch is a memory element whose excitation signals control the state of the device. A latch has two stages set and reset. Set stage sets the output to 1. The reset stage set the output to 0.
Flip-flops A flip-flop is a memory device that has clock signals control the state of the device. They flip from one state to another and then flop back.
The latch with the additional control input is called Flip-Flops • The additional control input is either clock or enables input.
The memory elements used in clocked sequential circuits are called Flip-Flops.
These circuits are binary cells capable of storing one bit of information.
A flip-flop circuit has two outputs, one for the normal value and one for the complement value of the bit stored in it.
Flip Flops are of different types depending on how their inputs and clock pulses cause a transition between two states. They are