| Shouri Chatterjee
Department of Electrical Engineering
What are Analog Circuits and what are their role in real life?
(Note: This page will not be of any use to people who are well versed in the sciences, especially in subjects as esoteric as quantum mechanics. ;-) QMech shows that the world is discrete.)
"Analog" is "analogous" to real life. In real life everything is "continuous". For instance let us take the temperature of a place. The temperature of a place varies over time - say yesterday it was 25 degrees and today it is 20 degrees. This change of temperature does not take place all of a sudden - the temperature goes through all of the temperatures in between 20 and 25 degrees when it changes. There are an infinite number of temperatures between 20 and 25 degrees. At one point of time the temperature was 20.1 degrees, at another point of time the temp was 20.5 degrees, at some other point of time the temp was 20.578 degrees, and at some other point of time the temp was 20.78900748 degrees. In general, between any two temperatures, however close they maybe, there are an infinite number of temperatures. This is the idea of "continuity".
In sharp contrast to this is a "digital" system - a stupid system, that
cannot understand continuous things. It can understand only "discrete"
signals - e.g '1', '2', '3' etc. It cannot understand anything between 1
and 2 - not even 1.5 . In electronics it is convenient to represent numbers like 1, 2, 3
etc using the binary system because '1' and '0' can be conveniently
related to "ON" and "OFF". (In normal day to day life we use the decimal
system. The use of the decimal system can be traced back to the presence
of ten fingers on our hands - which obviously proved to be very
convenient.) In the binary system one is 1, two is 10, three is 11, four is
100, five is 101, six is 110, seven is 111, eight is 1000 - and so on.
(The idea is to try to represent a number using only 1s and 0s.)
All digital equipment - starting right from your microwave oven, washing
machines, traffic lights to calculators and computers use the binary system
at their heart.
So how do we interact with these stupid machines which do not understand real life? That is where the analog designer comes in - his job is to shape analog data so that it is easy to convert it to digital. In the process we lose some information, yes (since the stupid digital system cannot even understand 1.5), and that cannot be helped.
In very short, analog signals are like "real numbers", where as digital
signals are like "integers".
The above picture is just an example of how sound looks like. It is a very small part of the entire soundtrack for the sound of a gong. As you should have figured out by now, sound is Analog.
Last updated on October 19 2016 at 11:57 IST