Saturday, March 10, 2012

Full and Half Subtractor

The Full Subtractor is a combinational circuit which is used to perform subtraction of three bits. It has three inputs, X (minuend) and Y (subtrahend) and Z (subtrahend) and two outputs D (difference) and B (borrow).


The Half Subtractor is a combinational circuit which is used to perform subtraction of two bits. It has two inputs, X (minuend) and Y (subtrahend) and two outputs D (difference) and B (borrow).


Truth Table for Half Subtractor:

XYDB
0000
0111
1010
1100
Schematic Diagram for Half Subtractor:

File:HalfSubtractor.svg

Truth Table for Full Subtractor:

xyzDB
00000
00111
01011
01101
10010
10100
11000
11111
Schematic Diagram for Full Subtractor:



3 comments:

  1. requires details description of circuit diagrams.

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  2. In all operations, each subtrahend bit is subtracted from the minuend bit. In case of the second operation the minuend bit is smaller than the subtrahend bit, hence 1 is borrowed.

    ReplyDelete