Question

What is ripple carry adder?

(a) The carry output of the lower order stage is connected to the carry input of the next higher order stage

(b) The carry input of the lower order stage is connected to the carry output of the next higher order stage

(c) The carry output of the higher order stage is connected to the carry input of the next lower order stage

(d) The carry input of the higher order stage is connected to the carry output of the lower order stage

I have been asked this question in class test.

This intriguing question originated from Fast Adder & Serial Adder in section Arithmetic Circuits of Digital Circuits

Answer 1

The correct option is (a) The carry output of the lower order stage is connected to the carry input of the next higher order stage

To explain I would say: When the carry output of the lower order stage is connected to the carry input of the next higher order stage, such types of connection is called ripple carry adder in a 4-bit binary parallel adder.