Page 10 - Computer - 3

CENTRAL PROCESSING UNIT (CPU)

The CPU is a small electronic chip fixed inside the CPU box. It
is placed in a slot on a large circuit board called Motherboard.
CPU is called the ‘Brain’ of the computer. It not only carries
out all calculations and computations, but also controls the

computer’s overall functioning. It receives data from an input
device, processes it according to the given instructions, and
sends it to an output device.

Knowledge Discovery Subject Enrichment

The CPU chip is also called the microprocessor due to its small size. CPUs comes

in different models which differ in their computational power.

The CPU is further divided into three units. These are:

1. ALU (Arithmetic Logical Unit)
The Arithmetic Logical Unit is the ‘Brain’ of the CPU. It performs all arithmetic

calculations and logical operations on the data. The ALU performs the job of
converting data into information.

2. CU (Control Unit)

The Control Unit is the ‘Heart’ of Central Processing Unit
the CPU. It controls the flow of Control Unit

data and instructions between
Input
the ALU and the Memory unit. Device Arithmetic Logical Unit Output
Device
It also controls the overall

functioning of the various parts
of the computer. Memory Unit

3. MU (Memory Unit)
The Memory Unit stores data and instructions for a short duration of time before
and after the processing respectively.

Let us understand the IPO cycle and how the CPU works with an example. We
want to subtract 20 from 50 and display the result.

1. We type 50 - 20 using the keyboard. This is input.
2. The input comes to the Control Unit (CU).
3. The CU stores the numbers 50, 20 and the - operator in the Memory unit.

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