the brain of any computer system is called ?

The brain of computer system is called central processing unit (CPU). Alternately its referred as a processor, central processor, or microprocessor, the CPU (pronounced sea-pea-you) is the central processing unit of the computer. A computer’s CPU handles all instructions it receives from hardware and software running on the computer. The CPU is a chip containing millions of tiny transistors. It’s the CPU’s job to perform the calculations necessary to make the computer work — the transistors in the CPU manipulate the data.

A central processing unit (CPU) is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions.