Adding 3 bit binary numbers

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Myzer

Joined Oct 27, 2016
1
I was just assigned a school project for engineering. The project entails me adding three 3-digit binary numbers together to get an output (ex. 101 + 001 + 111). I don't have a huge understanding with electronics quite yet, but I know that half adders are used to add one bit binary numbers (i think). So all in all i'm just really confused on how to go about this with my limited knowledge and would love some expert advice. Thanks!
 

ErnieM

Joined Apr 24, 2011
8,377
A half adder is a circuit to add two bits together to produce a 2 bit output, as 1+1=01. As such it is fine to add the first lowest bits together.

The higher bits need what is called a full adder to add the two bits from the inputs plus the carry from the previous lower bit.

Thus you will need one half adder and two full adder circuits to add three bits to get a four bit output.

Look up "adder" in Wikipedia to see one nice discussion.
 
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