What Is A CPU?

CPU refers to the Central Processing Unit of a computer. Typically called a processor, it is made of the ALU (arithmetic-logic unit), the instruction decoding unit and the CU (control unit). In present times one single chip represents a CPU. An input device like a keyboard or mouse, an output device like a monitor and the CPU make a computer system.

A CPU chip has a microprocessor, which is like the heart of the computer, a RAM (for the speed of the system) and a network of buses and channels (I/O architecture). A layman can correlate a CPU with the cabinet which contains the microprocessor, memory and other things which are in the cabinet. The control unit assembles and arranges the instruction from the main memory in an appropriate sequence and sends it to the instructing decoding unit to interpret them. The data is then transferred to the ALU unit through the main memory for processing.

The word CPU stands for is the Central Processing Unit which is a main part, or we can say, the brain of the computer. Its an important part of your computer which takes data as a input process it and generate output.
The working of CPU is just like the working of the Human brain. The Human brain receives the signals from the nervous system, processes those signals and makes decisions and then returns those signals back to their  origin. The same work is done by the CPU but in a different manner.
For example: If a user enters types the word Pictures so the command sent to the CPU is not Pictures it is decoded into machine language by supporting software which converts the user defined language into machine understandable language for the further process and decisions.  Then this command is sent to its destination where the installed helpful application software takes their decision regarding that command c from the user and then generate output on the basis of defined set rules and procedures in installed application software. After this process the command is returned from the software and sent to the processor where the process of conversion from machine language to user language is done again and the user sees the output of his entered command in the form of word Picture.
From this discussion it might come to your mind that if a CPU takes such a long time to process a simple command then what will happen if we write a document or give a command of "play the movie"? All this whole process is done on electrical signals which travel with the speed of light and the process is much quicker than explained in CPU.