8. Microphone {mic}
A mic converts the sound received
into computers format, which is
called DIGITIZED SOUND or
DIGITAL AUDIO.
A MIC can work if our PC has a
hardware known as SOUND CARD.
10. OUTPUT DEVICES
The output unit is responsible
for producing the output in
user redable form. Some of the
output devices are Monitor,
Printer, Plotter etc.
Computer sends output
through Monitor.
11. MONITOR
Monitor {or screen} is the most common
form of output from a computer. The
picture on a monitor is made up of
thousands of of tiny coloured dots called
pixels. The two most common Monitor
are Cathode Ray Tube and Liduid
Crystal Display .
12. Cathode ray tube
CRT contains an electron gun at
the back of the glass tube. This
fires electrons at groups of
phosphor dots, which coat the
inside of screen. When the
electrons strike the phosphor
dots they glow to give the
colours.
14. Liquid crystal
display
LIQUID CRYSTAL is the material
used to creat each pixel on the
screen. The material has a special
property –it can ‘polarise’ light
depending on the electrical charge
across it. This feature allows the
pixels to be created. THIN FLIM
TRANSISTOR is the device with in
each pixel that sets the charge.
16. printer
A most convenient and useful
method by which the computer can
deliver information is by means of
printed character. Printers can be
divided into two distinct categories.
1} Impact Printer.
2} Non-Impact Printer.
17. Impact Printer
In Impact Printers, there is
contact between the printer head
and paper.
Impact printer comes in lots of
varities such as Line Printer,
Drum Printer, Daisy Wheel
Printer and Dot Matrix Printer.
18. Dot-matrix Printer
A Dot-Matrix Printer is the most popular
serial printer i.e. it print one character at a
time. In, DMP, the printing head contains a
vertical array of pins. As the head moves
across the paper ,selected pins fire
against an inked ribbon to form a pattern
of dots on the paper. There are 80 column
and 132 column DMPs available in the
market.
19. Non-impact printer
In Non-Impact Printers, there is no
mechanism contact between the
printer head and paper.
The natural limitation of speed in
electromechanical devices and cost
consideration have led to the
development fo printers called Non-
Impact Printer.
20. Types of n-ip
i. Electromagnetic
Printers.
ii. Thermal Printers
iii. Electrostatic Printers.
iv. Inkjet Printer.
v. Laser Printer
