The Difference Between a Latch and a Flip Flop
Introduction
In digital circuits, latches and flip flops are two of the most commonly-used storage devices. Both of these devices are used to hold a value of either 0 or 1, and retain this value until it is updated.
While both latches and flip flops are used for memory storage, they differ greatly in their functions and the way they operate. In this article, we will discuss the differences between a latch and a flip flop.
What is a Latch?
A latch is an electronic circuit that is used to store a value. A latch can hold a value of either 0 or 1, which can be updated based on the input signal. The basic building block of a latch is known as a latch gate, which consists of two NOR gates and two NAND gates.
One of the key features of a latch is that once it has been set, the output value will remain until the input signal changes state. There are two types of latches: the SR latch and the D latch. The SR latch is the most common type of latch and is also known as a SET-RESET latch.
What is a Flip Flop?
A flip flop is also an electronic circuit that is used to store a value. A flip flop is a more complex circuit than a latch and can store more than one bit of information. Unlike a latch, a flip flop is designed to change its output based on the input signal.
There are several types of flip flops, including the D-type flip flop, the T-type flip flop, and the JK flip flop. The D-type flip flop is the most common type of flip flop, and is often used in digital applications.
The Differences Between a Latch and a Flip Flop
The main difference between a latch and a flip flop is the way they operate. A latch is designed to hold a value until the input signal changes state. Once the input has changed, the output of the latch will change to reflect this new value.
A flip flop, on the other hand, is designed to change its output based on the input signal. Unlike a latch, a flip flop will change its output only when a clock signal is applied. This makes a flip flop more reliable than a latch, since it eliminates the possibility of glitches and errors in the output.
Another major difference between a latch and a flip flop is the complexity of the circuit. A latch is a simple circuit that uses only a few transistors, while a flip flop is a more complex circuit that uses more transistors and gates.
Conclusion
In summary, latches and flip flops are two of the most commonly-used storage devices in digital circuits. Both devices are used to hold a value of 0 or 1, but they differ greatly in the way they operate and their complexity.
A latch is a simple circuit that is designed to hold a value until the input signal changes state, while a flip flop is a more complex circuit that changes its output based on the input signal and clock signal. Understanding the differences between these two devices is critical for anyone working with digital circuits.
Table difference between a latch and a flip flop
| Latch | Flip Flop |
|---|---|
| Has only one stable state | Has two stable states |
| Can be used for storing small amounts of data | Used for storing a single bit of data in digital circuits |
| Does not have a clock input | Has a clock input |
| Is level-sensitive and can be set or reset at any time | Is edge-sensitive and changes state only on the pulse of a clock |
| Latch circuit is simpler in design | Flip-flop circuit is more complex in design |