Binary addition of two 3 bit numbers can be done using this circuit. In this example the initial carry is given as 0. Then each bit starting from the LSB is added in the adder and the carry is passed to the next adder. Hence the name ripple carry adder - as the carry ripples through the adders. The main disadvantage in using this type of adders is that the time delay increases as for eah adder to add the carry should be generated in the previous adder, and for that to add the carry from the one before is required. So for a N bit adder each with a delay of 'd' the total delay comes to Nd.