Electronics and Communication Engineering - Digital Electronics - Discussion

Discussion Forum : Digital Electronics - Section 1 (Q.No. 22)
22.
The greatest negative number which can be stored is 8 bit computer using 2's complement arithmetic is
- 256
- 128
- 255
- 127
Answer: Option
Explanation:

The largest negative number is 1000 0000 = -128.

Discussion:
16 comments Page 1 of 2.

Jagdish said:   4 years ago
The Greatest negative number will be the smallest no. Since in negatives as no. Increases value decreases. So, the greatest 8 bit negative number is 10000000 = -128.

Tshering Dorji said:   5 years ago
Then, what is the way to find the largest negative and positive number for 1s complement and signed number?

Please, anyone, tell me.
(1)

Sumesh said:   7 years ago
+128 = 10000000,
-128 =2's compliment of 10000000,
=1's compliment of 10000000 +1,
= 01111111 +1,
=1000000.
(1)

Dhanya said:   7 years ago
-128 in 2's compliment form = 2's compliment of + 128.
+128 in binary form=01111111.
2's compliment of 01111111=10000001.
(1)

Dhanya said:   7 years ago
For 2's compliment representation, Range is {-2^(n-1) ) to +(2^(n -1))-1}.
Here n=8 ,then { (-2^(8-1)) to +(2^(8-1))-1}.
-2^7 to +(2^7)-1.
-128 to +127.

So, the greatest negative number in 2'compliment representation is - 128.
(2)

Pavan said:   7 years ago
And why 0111111 is largest? please explain.

Pavan said:   7 years ago
In 8bit, 11111111 is the largest right?

Divyesh Makwana said:   8 years ago
The largest Negative number in 8 bit is 01111111 and 2's complement of it in 10000000 which is -127.

Shubham said:   8 years ago
For 2's compliment.

The range is -(2^n-1) to +((2^n-1)-1) and this is different in the case of 1's and signed representation.

Sandy said:   9 years ago
No, the largest positive no is 127.

132,64,32,16,8,4,2,1.
0 1 1 1 1 1 1 1.


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