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# Understanding DECODER Is: Function & Truth Table

## Definition of Decoder

Decoder is a tool used to restore a decoding process so that we can receive original information. Decoder can also be defined as a series of logic that is useful for receiving binary input and then activating one of the outputs based on the size of the binary.

One function that is owned by the decoder is to provide convenience in expressing seven segments . This is the reason that makes us use decoders more when we want to turn on seven segments .

Some circuits that use decoders that you may often encounter are decoders with 3 x 8 or 3 bit 8 output line, 4 x 16 series or 4 input 16 output lines, BCD to 7 segment decoder with 4 input bits and 8 output line, and also BCD to Decimal type decoder which has 4 input bits and also 10 output lines.

Meanwhile, one of the most commonly used decoder ICs is 74138. This one IC has been equipped with 3 input bits and 8 output lines that have an input value of 1 on each of its output lines. On the other hand, the notion of a decoder at a glance is not much different from a demultiplexer. But the difference is that this decoder does not use input data. So, the available input is only used for data control.

Other definitions for decoders can also be formed through an arrangement of basic logic gates as well as those that use ICs and are sold in the market. Some types of decoders include: 74LS154, 74LS155, 74LS48, 74LS138, and so forth. With this IC, you can easily when you want to assemble decoders that have the bits and outputs that you want. For example, when you want to design a decoder with 32 output lines with an IC decoder that has 8 output lines.

## Decoder Function

Now we will move on to discuss the functions of the decoder . As we have explained that with a decoder, it will be easier for you to run seven segments. By using a decoder, the time to turn on seven segments does not require a long time. That way, you can save your time.

You should also know that the output of the decoder is a maximum of 2n. This makes you able to form an n to 2n decoder. When you want to compile a decoder, you have to make 3 to 8 decoders or by using 2 to 4 decoders. Eventually a 4 to 16 decoder will be formed which also uses 2 3 to 8 decoders.

## Decoder Requirements

You must know that the decoder must meet the requirements so that it can become a design. The requirements are m <2 n. The value m is a combination of outputs and for n represents the number of input bits. One of the inputs can only represent one combination of outputs.

## Decoder Truth Table

Truth Decoder Table

In the following we will provide information about what a decoder truth table looks like. But before that you should know that the decoder circuit is reversed compared to the encoder. That is, it converts a binary code into a discrete signal.

Below is a BCD decoder truth table that is connected to 7 segments that need to be understood before you start to string it.

## What's the Difference between Encoder and Multiplexer Decoder?

Encoder is a series of logic that is used to change code from what can be understood by humans to code that is not understood or even unknown to humans. As for decoding, it is a series of logic that is useful for converting codes that are not known to humans into codes that are known to humans.

It should be understood that the circuit owned by the encoder has several input lines in which one of several inputs has or must be activated at a certain time. Then, the input will produce an output code in the form of N-bits with a series which is a wagon application or

While for a series priority encoder is a priority series divided into two. For example if it turns out that there are two or more inputs that produce a value of '1' at the same time, then the input with the highest priority will be taken.

Then what about the decoder circuit? The decoder circuit actually consists of several types, namely:

• Decoder 3 x 8 where the input line is 3 and the output is 8.
• 4 x 16 decoder, where the input is 4 and the output is 8.
• BCD to Decimal decoder, meaning that this circuit has 4 bits of input and also 8 bits of output.
• BCD decoder to seven segments, where this circuit comes with 4 inputs and also 8 output lines.

There are important things which also may not be allowed ignored. Especially for the BCD to seven segment circuit, it has principles and ways of working that are not the same as other types of decoder circuits. The combination of each input it has can later activate several outputs which means it does not only come from one line.

On the other hand, a multiplexer is a logic circuit that is in charge of receiving digital data input and then selecting some or one of these inputs which will then be issued to its output line.

This multiplexer is useful for data collector where the incoming data will come from N sources. Then selected by selecting one of which will then be forwarded to a single channel. Enter the data can be in the form of several paths where each path has more or even just one bit.

This is the information we can give you about the meaning of decoders and their functions, decoder truth tables, and other related matters. Hopefully this information is useful.