Speakers receive the sound in the form of electric current from the sound card & convert it to sound format. These are used for listening music, chatting , seminars for presentations etc.
This is also called monitor. It is used to get the data in the form of soft copy. Their functioning is exactly similar to the television. It contains a CRT which emits the electrons to trace a regular pattern of horizontal lines on the screen.
Impact - Have mechanical contact in between paper & printing head
Non Impact - No mechanical contact between paper & printing head
Line Printers - print line wise (E.g. Drum Printer)
Character Printer - print character wise (E.g. Daisy Printer)
NON IMPACT -
These screens are used in laptops & notebook sized PCs. A special type of liquid is sandwiched between two plates. The top plate is clear & bottom plate is reflective. The molecules in these liquids are normally aligned & the computer signals are used to align these molecules.
LED (Light Emitting Diodes)