digital logic

Question

To implement a 5 bit binary adder, the minimum number of half adders required is ______________

Comments

9 ??

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yes ! can u explain?

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since for LSB bit c_in =0, it can be done with half adder for rest 4 bits full adders are required...
so in minimum total adders are required are 4 full adders + 1 half adder...
now, one full adder can be implemented with 2 half adders, so total half adders required are
4*2 + 1= 9..

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thank you :)

Answer 1

5 bit binary adder can be implemented using 4 full adder and 1 one half adder.

Further, these 4 half adders can be implemented using 8 half adders.

Total no of half adders = 9

Comments

Yes, that's true and the simple formula for this is

for n- bit binary adder we require (2n-1) half adders and (n-1) OR gates or n full adders.

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@raushank2 can you give any reference?