# What is full adder and subtractor?

## What is full adder and subtractor?

Design of Half Adders and Full Adders: A combinational logic circuit that performs the addition of two single bits is called Half Adder. A combinational logic circuit that performs the addition of three single bits is called Full Adder.

How can an adder be used as a subtractor explain with a diagram?

Such binary circuit can be designed by adding an Ex-OR gate with each full adder as shown in below figure. When M= 1, the circuit is a subtractor and when M=0, the circuit becomes adder. The Ex-OR gate consists of two inputs to which one is connected to the B and other to input M. When M = 0, B Ex-OR of 0 produce B.

### Why it is called Half subtractor?

Quite similar to the half adder, a half subtractor subtracts two 1-bit binary numbers to give two outputs, difference and borrow. Since it neglects any borrow inputs and essentially performs half the function of a subtractor, it is known as the half subtractor.

What is a full subtractor?

Full subtractor The full subtractor is a combinational circuit which is used to perform subtraction of three input bits: the minuend , subtrahend , and borrow in . The full subtractor generates two output bits: the difference and borrow out .

#### What is an adder subtractor circuit?

In digital circuits, an adder–subtractor is a circuit that is capable of adding or subtracting numbers (in particular, binary). It is also possible to construct a circuit that performs both addition and subtraction at the same time.

BCD adder A 4-bit binary adder that is capable of adding two 4-bit words having a BCD (binary-coded decimal) format. The result of the addition is a BCD-format 4-bit output word, representing the decimal sum of the addend and augend, and a carry that is generated if this sum exceeds a decimal value of 9.

## Which logic is used in adder subtractor circuit?

Arithmetic Logic Unit
In Digital Circuits, A Binary Adder-Subtractor is one which is capable of both addition and subtraction of binary numbers in one circuit itself. The operation being performed depends upon the binary value the control signal holds. It is one of the components of the ALU (Arithmetic Logic Unit).

What are two types of basic adder circuits?

### What is the function of half subtractor?

The half subtractor is also a building block for subtracting two binary numbers. It has two inputs and two outputs. This circuit is used to subtract two single bit binary numbers A and B. The ‘diff’ and ‘borrow’ are two output states of the half subtractor.

How is an adder circuit different from a subtractor circuit?

And the only difference is that input variable A is complemented in the full subtractor. Therefore, it is possible to convert the full adder circuit into full subtractor by simply complementing the input A before it is applied to the gates to produce the final borrow bit output Bo.

#### Can a subtractor be used as an adder?

As with the full adder, full subtractors can be strung together (the borrow output from one digit connected to the borrow input on the next) to build a circuit to subtract arbitrarily long binary numbers. Notice that subtractors are almost the same as adders.

What are the outputs of a half adder?

Half adder is a combinational logic circuit with two inputs and two outputs. The half adder circuit is designed to add two single bit binary number A and B. It is the basic building block for addition of two singlebit numbers. This circuit has two outputs carryand sum.

## Which is the circuit diagram for full subtractor?

The circuit diagram of the full subtractor using basic gate s is shown in the following block diagram. This circuit can be done with two half-Subtractor circuits. In the initial half-Subtractor circuit, the binary inputs are A and B.