Digital Logic Gates Logic Gate

Half Subtractor

October 18, 2018



The 0.5 subtractors may be a combinable circuit that is employed to perform subtraction of 2 bits. 0.5 subtractor is that the most essential combinable logic circuit that is employed in digital natural philosophy. Basically, this is often AN device or in alternative terms, we are able to say it as a logic circuit. 0.5 subtractor is employed to perform 2 binary digits subtraction. within the subtraction procedure, the number is going to be ablated from a number. The circuit of 0.5 subtractor consists of 2 inputs.




Block Diagram

Block-Diagram-Half-Subtractor

   Fig:  Block-Diagram-Half-Subtractor

The Subtractor could be a digital circuit that processes the subtraction of 2 1-bit numbers. In this, the 2 numbers concerned square measure termed as number and number. scrutiny a half-subtractor with a half-adder, it may be seen that the expressions for add and distinction output square measure same. The inputs of the subtractor circuit are number and number. On the opposite hand, the output is the distinction and also the borrow. we’ve got already mentioned the ideas of an adder and a full adder circuit that uses the binary numbers for the calculation.

Symbol

Symbol-Half-Subtractor

Fig: Symbol Half Subtractor

Before progressing to discuss the subtractor, we’ve to grasp the binary subtraction. In binary subtraction, the method of subtraction is analogous to arithmetic subtraction. In arithmetic subtraction, the bottom a pair of numeration system is employed whereas, in binary subtraction, binary numbers square measure used for subtraction. If we have a tendency to compare the mathematician expressions of the subtractor with an adder, we square measure able to see that the 2 expressions for the add and distinction are precisely the same and then they must be attributable to the Exclusive-OR gate operate. There square measure essentially 2 sorts of adders viz. adder and full adder same is that the case with subtractors. adder takes 2 single bits as input and produces an add and a carry output. within the below figure. the 2 mathematician expressions for the binary subtractor BORROW is additionally terribly the same as that for the adders CARRY.

Truth Table

Half_Subtraction

Fig: Half Subtraction Truth Table

The resultant of all the four inputs are represented as outputs. The output of 0.5 subtractors is represented in 2 columns. the reality table could be a key tool to know the operating of any digital circuit. the reality table is nothing, however, the attainable combination of inputs and their resultant output. once we observe the primary 2 and fourth rows, the distinction of those rows, then the distinction and borrow ar similar as a result of number is lesser than the number. As aforementioned higher than we will see that the distinction output is the same because of the added output of 0.5 adders. however, the Borrow is completely different from carrying of 0.5 adders.



Half Subtractor using NAND gates

NAND-Gate-Half-Subtractor

Fig: NAND Gate Half Subtractor

NAND circuit also can be wont to style 0.5 subtractor. the whole of five NAND circuit is employed for coming up with of Subtractor circuit. The circuit of the 0.5 subtractors is often designed with 2 logic gates particularly NAND and EX-OR gates. This circuit provides 2 parts like the distinction in addition because of the borrow. One major disadvantage of the 0.5 Subtractor circuit once used as a binary subtractor, is that there’s no provision for a “Borrow-in” from the previous circuit once subtracting multiple information bits from one another.

Half Subtractor using NOR gates

NOR-Gate-Half-Subtractor

Fig: NOR Gate Half Subtractor

The NOT-gate is one style of digital computer circuit with one input and supported the input the output is reversed. as an example, once the input of the NOT gate is high then the output is low. The two Boolean expressions for the binary subtractor BORROW is additionally terribly the same as that for the adders CARRY. Then all that’s required to convert a 0.5 adder to a 0.5 subtractor is that the inversion of the number input.

 

 

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