3rd Class Computers Science Input and Output Devices Output Devices

       Output Devices  

Any device that receives and/or displays information from a computer is called an output device. Output devices are pieces of computer hardware that allow a computer system to communicate information to a user or another system. This information can be in any form and includes text, sound, images, etc. Output devices such as a printer, video display or speaker present data from a computer to a user. Thus we see that output devices are things we use to get information out of a computer that has been held or generated within a computer. Output devices show the result after processing the data into information. We can get output in two forms - The Hard Copy Output and the Soft Copy Output. The output seen on the monitor or heard through the speakers/ headphones is the soft Copy Output. The output obtained on the paper (through printers) is called the Hard Copy Output. Since most information from a computer is output in either a visual or auditory format, the most common output devices are the monitor and speakers. These two devices provide instant feedback to the user's input, such as displaying characters as they are typed or playing a song selected from a play list. While monitors and speakers are the most common output devices, there are many others. Some examples include headphones, printers, projectors, lighting control systems, audio recording devices and robotic machines. Let's discuss about some common output devices.  

     Monitor

Monitor is an output device that resembles the television screen and uses a CRT (Cathode Ray Tube) to display information. It is associated with a keyboard for manual input of characters and displays the information as it is keyed in. It also displays the program or application output. Thus, the monitor displays the results of the computer's activities on the screen. Like the television, monitors are also available in different sizes. The display device modern monitors is typically a TFT-LCD (Thin Film Transistor Liquid Crystal Display). It is an essential output device without which the computer cannot work. A monitor is also called a visual display unit.  

     Printer  

Printers are output devices used to produce paper (commonly known as hardcopy) output of documents stored in an electronic form. Based on the technology used, they ran be classified as Impact and Non-Impact printers. Impact printers use the typewriting printing mechanism wherein a hammer strikes the paper through a ribbon in order to produce output. Dot-matrix and Character printers fall under this category. Non-Impact printers do not touch the paper while printing. They use chemical, heat or electrical signals to fetch the symbols on paper. Inkjet, DeskJet, Laser, Thermal printers fall under this category of printers. Printers are generally slow devices (30 pages per minute are considered fast) and the cost per page is actually relatively high. As printers have improved in quality and performance, many jobs which used to be done by professional print shops are now done by users on local printers.   

 Given below are the few statements about output devices. Select the correct one.

1. Any device that feeds/ inserts information to the computer is called an output device.

2. Output devices such as a printer, video display or speaker present data from a computer to a user.

3. Monitor uses a cathode ray tube to display information.

(A) 1 and 2                                                         

(B) 1 and 3

(C) 2 and 3                                                          

(D) All of these

(E) None of these  

Answer: (C)

Explanation

Correct Option:

(C) Statements 2 and 3 are correct about output devices. Therefore, option (C) is correct.

Incorrect Options:

(A) Statement 1 is incorrect whereas statement 2 is correct. Therefore, option (A) is incorrect.

(B) Statement 1 is incorrect whereas statement 3 is correct. Therefore, option (B) is incorrect.

(D) All the given statements are not correct. Therefore, option (D) is incorrect.

(E) All the given statements are not incorrect. Therefore, option (E) is incorrect.    

 Fill in the blanks:

1. _____ printers use the typewriting printing mechanism wherein a hammer strikes the paper through a ribbon in order to produce output.

2. _______ printers do not touch the paper while printing.

3.  A ______ is also called a visual display unit.

(A) Impact, Non-Impact and Monitor

(B) Non- Impact printer. Impact and Screen

(C) Laser, Dot- matrix and Monitor

(D) Laser, Impact and Monitor

(E) Dot-matrix, Impact and Screen

Answer: (A)

Explanation

Correct Option:

(A) Options given in (A) are correct. Therefore, option (A) is correct.

Incorrect Options:

(B) Options given in (B) are incorrect. Therefore, option (B) is incorrect.

(C) Options given in (C) are incorrect. Therefore, option (C) is incorrect.

(D) Options given in (D) are incorrect. Therefore, option (D) is incorrect.

(E) Options given in (E) are incorrect. Therefore, option (E) is incorrect.