Combinational Circuits - GATE CSE Notes

In digital electronics, a combinational circuit is a circuit in which the output depends on the present combination of inputs. Combinational circuits are made up of logic gates. The output of each logic gate is determined by its logic function.

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What are Combinational Circuits?

A combinational circuit is a digital circuit whose output depends not only on the present input but also on the sequence of past inputs. The output of a combinational circuit can thus be considered as a function of all the inputs, past and present. This type of circuit is contrasted with a sequential circuit, in which the output depends not only on the present input but also on the state of the circuit, i.e. its previous history.

Applications of Combinational Circuits

A combinational circuit is an electronic circuit in which the output depends on the present combination of inputs. Combinational circuits are used in digital electronics, such as computers, to perform operations on data.

An example of a combinational circuit is a full adder, which takes two binary digits as input and produces a sum bit and a carry bit as output. Full adders are used in many digital devices, including calculators and computers.

Another example of a combinational circuit is a multiplexer. A multiplexer takes several input signals and selects one of them to be passed to the output. Multiplexers are used in many applications, including data communication and computer memory.

Combinational circuits can be made using various logic gates, such as AND gates, OR gates, and NOT gates.

Types of Combinational Circuits

There are three main types of combinational circuits: decoders, encoders, and multiplexers.

Decoders are combinational circuits that convert binary code into a form that can be read by a human. For example, a decoder might take a four-bit binary number and convert it into a seven-segment display.
Encoders are combinational circuits that convert information from one form to another. For example, an encoder might take a seven-segment display and convert it into a four-bit binary number.
Multiplexers are combinational circuits that select one of several input signals and send it to the output. For example, a multiplexer might take four input signals and send only one of them to the output.

Video on Combinational Circuits

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