Electronics changed the world and digital electronics has changed electronics. This digital electronics is different from analogue electronics. Before starting discussion on digital electronics I think it’s better to have some discussion on analogue and digital concept.
Time is changing continuously and your analogue watch dial changes continuously. Your car speedometer with needle, mercury thermometer, manometer with needle all are analogue. Real world values changes continuously and your analogue machines respond with that.
On the other hand digital measurement and signal is totally different. They are represented with discrete quantities. Time changes continuously but your digital watch shows change after certain period.
From the very beginning electronics was analogue, it dealt with changing signals like sine wave. Continuous changes in input are reflected in output. So electronics deals with continuous changes in voltage and current are analogue electronics.
Generally speaking digital electronics deals with digital signal and they also process digitally. So question is what digital signal is. Digital signal has discrete values and it can be represented numerically. Usually digital systems have two states. One is cut off voltage and the other is saturated. These two states are represented by 0 and 1. Usually zero voltage represents o and 5 volt represents 1. That means digital signal and digital data has only two digits, i.e. 0 and 1.
This processing is done using binary arithmetic and hence Boolean algebra is very important in digital world.
So a digital device means it’s processing is different. Now question is why this peculiar method when real world is analogue, their values changes continually?
Everything in our world is analogue so every digital system needs to convert analogue data to digital format before processing and storing. Moreover digital system converts digital data to analogue data before giving you the output. That’s a disadvantage. In spite of that digital systems are preferred. Voltage and current may change slightly due to faulty components and many other things. But it’s not a problem for digital system it will recognize 0.5 volt as zero and even 6 volt as one. So information storage and signal transmission is easy. Digital circuits are easy to design and operation can be programmed. It’s easy to make IC (Integrated Circuit) for digital circuits than analogue circuits.