Digital Electronic: Analog and Digital

Digital electronics is the sub-branch of electronics that deals with digital signals for processing and controlling various systems and sub-systems. In various applications like sensors and actuators, usage of digital electronics is increasing extensively. Mainly the analog realm of electronics - circuits that accept and respond to voltages that vary continuously over a given range. Such analog circuits included rectifiers, filters, amplifiers, simple RC timers, oscillators, simple transistor switches, etc.
Although each of these analog circuits is fundamentally important in its own right, these circuits lack an important feature - they cannot store and process bits of information needed to make complex logical decisions. To incorporate logical decision-making processes into a circuit, you need to use digital electronics.
In digital electronics there are only two voltage states present at any point within a circuit. These voltage states are either high or low. The meaning of a voltage being high or low at a particular location within a circuit can signify a number of things.