Introduction To Digital Electronics

The most widely used branch of electronics in modern era is digital electronics. Starting from the gadgets that we use on regular basis to lifesaving equipment and military defense technologies, this branch of electronics is responsible for designing it all.

Concepts of digital electronics is easy and straightforward. It is also easier to learn and master compared to other branch of electronics like analog electronics. It is straight forward because it is based on logic. In simple terms, digital electronics is a Yes/No decision/logic based electronics discipline. Any and all inputs have to be either Yes or No. The output is also either Yes or No. The Yes and No are defined by voltage levels. In terms of digital electronics, Yes is called HIGH and No is called LOW.

A digital system takes in input(s) and process the input(s) using some predefined rules. If the input passes the rules, the output is HIGH or positive, showing a pass. Else the output is LOW or negative, showing a fail. In digital systems, there is no maybe or in-between. Note that, all digital electronics components or devices or systems has an inherent predefined set of rules that is used to process the input(s) and provide the proper output(s).

Both HIGH and LOW is denoted by voltage level. The voltage levels depend on the digital logic family. There are several different digital logic family. Throughout the blog, we are going to use the most widely used digital logic family. It is called Transistor Transistor Logic (TTL for short). In TTL family, the voltage level for HIGH is anything between 2.4v to 5v. Voltages from 0v to 0.4v is called LOW. Any voltage between 0.5v to 2.3v is invalid (and is called Metastable). Refer to the diagram below.