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Speaker
Speaker is an output device that converts the electrical signals into sound waves that we hear. In speakers, the
electric current of the music files is supplied to the magnet that pushes the diaphragm of the speaker back
and forth. This creates pressure and vibration in the air and as a result, sound is produced.
Monitor
Monitor is a standard output device. It is also known as VDU (Visual Display Unit) or Screen. Monitor is used
for interactive processing i.e., the data being fed is displayed on the screen. It resembles a television.
In the graphics mode, the pictures are displayed by a combination of dots. The screen is treated as an array of
tiny dots called ‘Pixels’. In the graphics mode, there is a resolution of 640 dots across and 480 dots vertically
on the screen. There are different types of adaptors that support the display of graphics.
The higher the resolution, i.e., the more the number of pixels, the better the quality of the picture that is
displayed on the screen. DPI (dots per inch) is the unit of measurement of resolution applied to printers,
scanners, monitors, etc. Many computer systems and portable devices like laptops, PDAs, etc. have Liquid
Crystal Display (LCD) or LED monitors.
Central Processing Unit
Central Processing Unit (CPU) is the processing device. IT is also known as the ‘Brain of a Computer’. It is a
hardware component and also an important functional component of a computer system. It takes information
from the input unit or memory and processes it as per the given instructions. Processing includes calculations,
comparisons, decision making, etc.
Functional Elements of a CPU
The functional elements of a CPU can be divided into three parts:
Arithmetic Logic Unit (ALU)
Control Unit CU)
Memory Unit (MU)
Arithmetic Logic Unit (ALU)
ALU performs all logical and arithmetic operations. ALU performs arithmetic calculations (addition, subtraction,
division, multiplication, etc.) and does logical comparisons (greater than(>), less than(<), equal to (=), not equal
to(!=), etc.). ‘Logical Operation’ refers to comparison as it sets the sequence of operations. It differentiates
between ‘TRUE’ and ‘FALSE’. It receives the coded data and manipulates them to produce information in machine
code and then sends them to the Control Unit.
Control Unit (CU)
Control Unit coordinates and directs the operation of
the hardware devices. It also coordinates the flow and
execution of the data and instructions that are fed
into the computer’s memory. CU functions in an FDES
(Fetch-Decode-Execute-Store) cycle.
It fetches the instruction and data from the memory unit and decodes them and passes them to the ALU for
further processing. It also directs the ALU to execute the instruction and perform the required operations on
the data.
ICT Skills-I 51

