loader image

4 bit Ripple Carry Adder

A full adder can be used to perform addition of two bits with an input carry. To add an N-bit number, multiple full adder circuits can be cascaded parallelly. Such an arrangement of full adders is called a parallel adder. N full adders are required to add n bits.

A ripple-carry adder is a parallel adder created by connecting carry output of each full-adder with the carry input of the next higher-order full-adder. The input carry should occur first to produce the sum and output carry of any stage (a stage is one full adder); this causes a time delay in the addition process.

4 bit Ripple Carry Adder

A 4-bit binary ripple-carry adder is shown in the figure.


Full-adder 1 (FA1) cannot produce a potential carry until an input carry is applied. Full-adder 2(FA2) cannot produce a potential output carry until FA1 produces an output carry, Full-adder 3(FA3) cannot produce a potential output carry until FA2 produces an output carry and so on. That is the input carry has to ripple through all the adders before a final sum is produced. This causes a time delay in the addition process and is called propagation delay or ripple carry delay.

Further Reading

Notify of
Newest Most Voted
Inline Feedbacks
View all comments

On clicking the link provided, it takes to a page saying

“This page could not be found!

We are sorry. But the page you are looking for is not available.

Perhaps you can try a new search.”

The marked text in the attached image is what I clicked.


🙁 🙁

Scroll to Top