IO devices:
Input output devices.
Also known as:
Peripheral device (or) computer peripheral.
Peripheral:
Device used to put information and get information out of the computer.
Different peripheral devices:
Input devices.
Output devices.
Storage devices.
Device:
Unit of hardware.
Input device:
Computer hardware used to enter data for processing.
Types:
Keyboard:
To enter data and instructions to computer.
Set of keys like type writer.
Alphabetic keys a, b, c.....z (or) A, B, C...Z.
Numerical keys 0, 1, 2, 3...9.
Functional keys F1, F2......F12.
Editing like Delete, Backspace.
Control motion of pointer on screen.
Two or three buttons called Left, Right and Middle.
Rubber ball or metal ball inside its body.
Rolled over flat space called Mouse pad.
Like mouse.
1.5 to 2 square inch.
.
Light pen:
Connected to computers monitor.
Points screen with pen and select items.
Enter sounds into computer.
Help of microphone and sound card.
Save picture or text on paper binary form to computer memory.
Save our time to type lot of text.
Atm's and smartphones.
Enter data by touch his finger on menu option present on touchscreen.
Saved on digital camera internal memory.
Input these pictures with help of data cable into computer memory.
Advantages:
Fast entry of texts to document.Well known method of data entry.
Easy to use.
Verification test is easy.
Disadvantages:
People with limited arm does not find it easy.
Use up valuable desk space.
Output devices:
Receives data from computer.
Convert data in to human readable form.
Display result to users.
Types:
Monitor:
Computer screen or display.
TV like shape.
Picture on monitor element formed with pixel.
Display result in multi colors.
Produces soft copy output.
Karl Ferdinand Braun, in 1905.
Difference between Monitor and TV:
Monitor does not have a television tuner to change channels.
Higher display resolution than television.
Screen of computer:
Physical surface on which visual information is presented.
Made of glass.
Measured from one corner to opposite corner diagonally.
Inches are 12, 14, 17, 19, 21.
Computer screen invention:
In 1929, Zworykin.
Can we rotate monitor screen:
 |
| Original screen |
 |
| Right click and go to display settings |
 |
| Change to portrait |
 |
| Apply changes |
 |
| Save changes screen will change to portrait |
Use of monitor:
Less desk space.
Light weight.
Less electricity than CRT.
Types of monitors:
CRT (Cathode Ray Tube):
Old model monitor.
More space.
High power consumption.
Supports low resolution.
Flatter type of computer screen.
Light weighy.
Occupy less space.
Low radiation but supports high resolution.
Flat screen.
Same as LCD's but better picture quality in LED monitors.
Processors:
Electronic circuit that perform calculations to run computer.
Small chip that recides in computer and other electronic devices.
Processor of computer:
CPU (Central Processing Unit) is brain of computer.
Handles basic system instructions such as Mouse, Keyboard.
What does CPU do:
Sends signals to control other parts of computer.
What does processor do:
Gathers from decoding the code in programs and other such files.
How processor work in computer:
Converts data input to information input.
Types of processors:
Dual core, Triple core, Quad core processor instead of one core traditional one chip.
Intel pentium dual core processor:
Great desktop performance.
Intel i3 processor:
Provides 4 way multiasking.
Runs at fixed speed ideal.
Intel i5 processor:
Same as i3 but intel turbo boost technology.
Delivers extra speed when we need.
Intel i7 processor:
8 way-threading.
More power.
High end use, video and gaming.
How to find which processor we have:
 |
| In start button enter msinfo 32.exe |
 |
| We can see processor we are having in our computer. |
Printer:
Device accepts text and graphic output from computer and transforms information to paper.
Hard copy output.
In 1938, Chester carlson invented dry printing process called electrophotography called xerox.
How printer works:
Laser beam scan back and forth across drum inside printer.
Static electricity attracts to page a kind of powdered ink called toner.
Fuser units bond the toner to paper.
Used for:
Higher resolution color printing.
Classification:
Use toner to produce image.
Toner:
Mix of carbon powder and iron oxide used in laser printers to form printed text and images on web.
Use ink to produce image.
Sprays ink on to the paper.
Differences:
| Laser printer | Inkjet printer |
|---|---|
| Laser printers takes more space. | Inkjet printers takes less space. |
| More expensive. | Less expensive. |
| More reliable. | Not more reliable. |
| Use more power. | Less power but used for many other functions. |
| It can print 20 pages per minute, speed is more. | It can print 6 pages per minute, speed is less. |
| Capable of black and white pages. | Capable of black, white, color pages. |
| Printing quality is higher and easy to maintain. | Printing quality is low and not easy to maintain. |
Thermal printers:
Uses heat to create image.
Digital printing process produces printing image selectively heating coated thermocromic or thermal paper.
Early fax machines used thermal printing.
Types:
Direct thermal.
Thermal wax transfer.
Direct thermal:
Burns dots on to special coated paper.
Used as receipt printers.
Uses ribbons that contains wax based ink.
Heating element melts ribbon on to thermal power.
Used to print receipts, barcodes.
Easy to maintain.
Dot matrix printer:
Placing dots to form image.
Striking pins against ink ribbon to print closely spaced dots in appropriate shape.
Expensive but does not produce high quality.
Each dot is produced by wire or pin.
Uses print ahead that moves back and forth, upwards and downwards.
Printer contains pins called printhead.
Ribbon is transferred through top copy of carbon paper or carbonless paper beneath it.
Cash registers.
Atms's.
DPI (Dots Per Inch):
Measure resolution of image both on screen and in print.
DPI increases image quality increases.
DPI on printer:
DPI output resolution on printer and PPI output resolution of photograph.
Image produced as real physical entity.
Why DPI:
A 100 dpi printed image means 100 dots per every square inch.
DPI when used in software it is PPI (Pixel Per Inch).
DPI for printers:
Dot matrix 60 to 90 DPI.
Inkjet 300 to 720 DPI.
Laser 600 to 2,400 DPI.
Applications:
Display blurry.