digital adder circuits

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gorejena ashford

Joined May 19, 2012
1
hello everyone.Im stuck on the following question:a student designed a parallel binary adder for industry to add two 3 bit binary numbers together and display the sum and carry words in decimal on seven segment displays.The student wanted to economise the design and used a HAlf ADDER for the least and most significant bits.A FULL ADDER was used for the middle bits.If 5 and 7(decimal) are input,what will the sum word in decimal?
 

t_n_k

Joined Mar 6, 2009
5,447
A=101 [decimal 5]
B=111 [decimal 7]

LSB [Bit '0'] Half Adder
A(0)=1
B(0)=1
Sum(0)=0
Carry_out(0) =1

Middle Bit [Bit '1'] Full Adder
Carry_in(1)=Carry_out(0) =1
A(1)=0
B(1)=1
Sum(1)=0
Carry_out(1) = 1

MSB [Bit '2'] Half Adder
A(2)=1
B(2)=1
Sum(2)=0
Carry_out(2)=1
 
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