Q. Basic introduction of Analog Building Blocks?

Electronic systems usually process information in either analog or digital form. In order to process the two different kinds of signals, analog circuits and digital circuits have been devised. While almost all technology was of the analog type until around 1960, due to the advent of integrated circuits (ICs), digital technology has grown tremendously.

In analog systems, a signal voltage or current is made proportional to some physical quantity. Since voltages (or currents) can take on any values over a continuous range between some minimum and some maximum, analog systems are also known as continuous-state systems.

These are to be distinguished from digital or discrete-state systems, in which only certain values of voltage (or current) are allowed. Most circuits found in analog systems are linear circuits in which one voltage (or current) is meant to be linearly proportional to another. Linear active circuits are also known as amplifiers, which are the building blocks of linear systems with analog technology.

When describing and analyzing electric systems,which are often large and complex, it is very helpful to consider such large systems as being built from smaller units, called building blocks. These are then the subunits, which can be connected to form larger circuits or systems. More importantly, the building blocks can be described adequately by their simple terminal properties. Thus, with the building block point of view, one is not concerned with the interiors of the blocks, only with how they perform as seen from the outside.