# Codes in Digital Electronics

In digital electronics, codes are used to communicate the information between computers. These codes represent the information symbolically as a string of bits 0 and 1 and rules defined by the code decide the arrangement of these bits.

Codes can be broadly categorized into three categories 1) Weighted Codes 2) Unweighted Codes 3) Sequential Codes

### Weighted Codes

These codes are positionally weighted and each position with in the binary equivalent of the number is assigned a fixed value. Thus, they obey positional weighting principal.

Binary Coded Decimal(BCD) is an example of weighted codes. In this code, the binary equivalent of a number will always remain same.

To understand how to compute bcd equivalent of a number, you may refer below link:

### Unweighted Codes

These codes are not positionally weighted i.e. each position with in the binary equivalent of the number is not assigned a fixed value. Thus, unweighted codes do not obey positional weighting principal.

Grey code is an example of unweighted codes.In grey code, computation not only depends on the bit under consideration but also on the neighboring bits. Due to which, unlike weighted codes, the binary equivalent of a number may return different values on each computation Excess-3 code is also an example of unweighted code.

To understand how to compute grey code or excess-3 equivalent of a number, you may refer below link:

### Sequential Codes

A code is said to be sequential when each succeeding code is one binary number greater than the preceeding code. BCD and Excess-3 codes are examples of sequential codes in digital electronics.

Thus, this post summarizes various codes used in digital electronics to communication information.

Feel free to leave your footprints in the comments section below for any queries, suggestions or feedback.

1. Hey dear, for your kind information excess-3 code is not a weighted type of code . Even though it is derived from BCD(which is weighted),it does not follows positional weighting principle.

• Hi Swapnil,

I have been meaning to update this information since a few weeks but was busy with other projects. Thank you very much for pointing this out and pushing us to correct it right away. We have updated the post.

Regards

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3. What you understand that Codes are based on two types:
1. Error detecting code
2. Error correcting code

And other based on Codes are three types:
1.Binary weighted codes:- 8421,5421,2421&5211 etc.
2.Sequential codes:- BCD, Excess-3 code etc.
3.Non-weighted binary codes:-Grey code,Excess-3 code etc.