Understanding Digital Logic Circuits: Input and Output Structures

The question asks to identify a digital logic circuit characterized by having a single input and multiple outputs. Let's examine the options provided to understand their typical input and output configurations.

Analyzing the Options

• De multiplexer: A De multiplexer, often abbreviated as Demux, is a combinational logic circuit. Its primary function is to take a single data input line and switch it to one of several output data lines. The selection of which output line receives the input data is controlled by a set of selection lines (or control inputs). Thus, a standard De multiplexer has one data input and multiple data outputs. This structure aligns with the description in the question.
• Decoder: A Decoder is another combinational logic circuit. It converts binary information from its inputs into a unique output line corresponding to the binary input code. A decoder with \(n\) input lines can have up to \(2^n\) output lines. For example, a 2-to-4 decoder has 2 inputs and 4 outputs. Decoders typically have multiple inputs and multiple outputs.
• Full Adder: A Full Adder is a combinational circuit used for adding three single-bit binary numbers. It takes two input bits (the bits to be added) and a carry-in bit from a previous stage. It produces two outputs: a sum bit and a carry-out bit. A Full Adder has 3 inputs and 2 outputs. It has multiple inputs and multiple outputs.
• Multiplexer: A Multiplexer, or Mux, is the opposite of a De multiplexer. It is a combinational circuit that selects one of several input data lines and routes it to a single output line. Similar to the Demux, the selection is controlled by selection lines. A multiplexer has multiple data inputs and one single data output. This structure does not match the description of having multiple outputs.

Based on the analysis of each circuit's input and output structure, the circuit that fits the description of having a single input and multiple outputs is the De multiplexer.

Comparison of Input/Output Structures

Here is a summary comparing the input and output characteristics of the circuits mentioned:

As the table clearly shows, the De multiplexer is the circuit that uniquely features a single data input and multiple data outputs, controlled by selection lines.

Revision Table: Digital Logic Circuit Concepts

Reviewing key terms related to the question:

Additional Information: Demultiplexer Details

The De multiplexer is an essential building block in digital electronics and computer systems. Let's delve a bit deeper into how a De multiplexer works and its common applications.

How a De multiplexer Works

A De multiplexer has:

• One Data Input (\(D_{in}\)).
• \(n\) Selection Lines (\(S_0, S_1, ..., S_{n-1}\)).
• \(2^n\) Data Outputs (\(Y_0, Y_1, ..., Y_{2^n-1}\)).

The selection lines \(S\) form an \(n\)-bit binary number. This binary number determines which of the \(2^n\) output lines will receive the signal from the data input \(D_{in}\). All other output lines remain at a logic '0' (or high impedance, depending on implementation).

For example, in a 1-to-4 De multiplexer (\(n=2\), so \(2^2=4\) outputs):

• It has 1 Data Input (\(D_{in}\)).
• It has 2 Selection Lines (\(S_0, S_1\)).
• It has 4 Data Outputs (\(Y_0, Y_1, Y_2, Y_3\)).

The truth table would look something like this:

When \(S_1 S_0 = 00\), the input \(D_{in}\) is routed to \(Y_0\). When \(S_1 S_0 = 01\), \(D_{in}\) goes to \(Y_1\), and so on.

Applications of De multiplexers

• Data Distribution: Routing data from a single source to multiple destinations.
• ALU (Arithmetic Logic Unit): Directing the output of the ALU to different registers or memory locations.
• Control Signals: Directing a single control signal to activate one of several devices.
• Memory Decoding: Though Decoders are more common for selecting memory locations, Demux can also be used.
• Serial-to-Parallel Converter: Can be used to convert serial data (data arriving one bit at a time) into parallel data (data available simultaneously on multiple lines).