CPU Central Processing Unit The CPU is the control center for a computer. It guides, directs & governs its performance. It is the brain of the computer. CPU CONTAINS : 1. Arithmetic & Logical Unit 2. Control Unit ARITHMETIC & LOGICAL UNIT An Arithmetic and Logical Unit (ALU) is a digital circuit  that performs arithmetic and logical operations. The ALU is a fundamental building block of the central processing unit (CPU) of a computer. ALU is a combination of Arithmetic Unit & Logical Unit. ARITHMETIC UNIT Arithmetic Unit performs all the arithmetic operations like addition , subtraction , multiplication & division performed on the operands. For example : a + b a - b a * B a / b CONTROL UNIT Control Unit is most important part which controls all the internal as well as external functions in the computer. THE MAIN FUNCTIONS PERFORMED BY THE CONTROL UNIT ARE : 1. It controls & guides the interpretation , flow    & manipulation of all data & information. 2. It sends control signals until the required operations are done properly by ALU & memory. 3. It gets program instructions from memory & executes them one after another. 4. It controls the flow of data from input device to memory & from memory to output devices.			CPU HARDWARE