1. North-Eastern Regional Institute of
management

2. Pronounced as separate letters, CPU is the abbreviation for central
processing unit. Sometimes referred to simply as the central
processor, the CPU is the brains of the computer where most
calculations take place. In terms of computing power, the CPU is
the most important element of a computer system.
In other words A central processing unit (CPU), also referred to as a
central processor unit, is the hardware within a computer system
which carries out the instructions of a computer program by
performing the basic arithmetical, logical, and input/output
operations of the system.

3. Block diagram of cpu
CPU
Control Unit
Input Output
Device ALU Device
Primary Memory
Secondary
Memory

4. Basic Components of CPU
 Control Unit(CU): which controls all the operations of
computer system
 Arithmetic & Logical Unit: which performs all
arithmetical & logical operations . Arithmetical
operations include addition , multiplication, division,
subtraction . Logical functions include <,>,= etc
 Memory(Register) : which holds the temporary data
for specific function.

5. Control Unit
CU
 Part of the hardware that is in-charge
 Directs the computer system to execute stored
program instructions
 Communicates with other parts of the hardware

6. Arithmetic & Logical Units
 Calculations occur here
 It knows how to perform operations such as
ADD, SUB, LOAD, STORE, .
 It knows the commands that make up the
machine language of the CPU
 It is the calculator

7. Registers
High-speed
Temporary storage
Located inside CPU
Instruction register Data register
Holds instruction currently Holds data waiting to be
being executed processed
Holds results from processing

8. How do CPUs work?
Control Unit- Manages four basic operations
(machine cycle)
Fetch- Gets next program instruction from the computer’s memory
Decode- Figure out what the program is telling the computer to do
Execute- Perform the requested action
Write-back (Store)- Write (store) the results to a register or to memory

9. How a CPU works
Control unit ALU
Memory

10. Example How CPU works

11. What’s inside the CPU?
Motherboard (mainboard)- Large printed circuit board with
thousands of electrical circuits
Power supply- Transforms alternating current (AC) from wall
outlets to direct current (DC) needed by the computer
Cooling fan- Keeps the system unit cool
Internal Speaker- Used for beeps when error is encountered
Drive bays- Housing for the computer’s hard drive, floppy
drive and CD-ROM / DVD-ROM drives

12. INSIDE CPU

13. What are the types of Processor?
Intel
Pentium IV Advanced Micro
Pentium III Devices (AMD)
Pentium MMX
Cyrix
Motorola (Apple)