PERIPHERALS

They are auxiliary devices that add functionality to a computer, they can be:

• Input devices. They gather information and send it back to the CPU as binary code.

• keyboards:are Input devices with different inputs buttons that represent each letter, number and sign. It transforms the binary code into characters.


• Mice: It helps you to interact with the interface by moving an object with a laser tracker that puts those tracking points into a vector position on the computer.


• Scanner: this device use optical sensors to transform a hard copy into a digital image. 

• Output devices. They do the reverse operation; transforming code into something that everybody can understand. 

• Screens: They transform the code from the computer into pixels, displaying videos, images and text. they can have different connections: VGA, HDMI, DVI...
• Speakers: These devices receive information from the sound card and with different circuits and amplifiers they can reproduce the sound effectively.
• Printer: it transforms digital data into hard copy. 
• There are different types, that use toner, ink, solid ink... which price can vary from £10 to almost £200. Their prices are directly related with the printer price. 
• The speed of the printer is measured in PPM (page per minute). It depends on the dimensions of the paper, the inks and the printing technology:
• Non-Impact Printers: laser, fast and efficient, but very expensive; ink-jet, cheap although it's not reliable.
• Impact Printers: dot-matrix, daisy-wheel, line, drum, chain and band printers. The last types of printers are old fashioned due to its noise, unreliability and low resolution.