The word computer comes from the word compute which means to calculate so a computer is normally considered as a computing device that can perform arithmetical operation at an a high speed. Computer had a great impact in our everyday life.
Analog computer process information of physical nature, that uses the continuously changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. Ex:- Temperature , Pressure , etc.
Digital computer process information in the form of 0 and 1(bit) is known as binary number. In Computing term we mostly refer to digital type of computer. Digital computer fall in different ranges called Micro Computer , Mini Computer, Mainframe Computer, Super Computer .
It is a combination of digital computer and analog, both. The digital component normally serves as the controller and provides logical and numerical operations, while the analog component often serves as a solver of differential equations. .