Chapter 2 Q2 Input and output devices

Computer Education CHAPTER 2

Q 2: What is meant by input? Write a detailed note on input devices of a computer.

Input:
Input means to enter anything. Suppose we enter carrot in a juicer and it provides us juice of the carrot, so to get juice first we have to enter carrot into the juicer. In Computer sciences, first we have to enter data in the computer so that the computer can act on it.

Input devices

“The devices through which we can enter data into a computer are called input devices.”
Through input devices we can enter data, information, and instructions in a computer. Following are the different input devices of a computer.

Keyboard:
A keyboard is the most commonly used input device. We can enter all types of data through keyboard. We can enter alphabets, numbers, characters and symbols in a computer through the keyboard. The Keyboard has different buttons, which are called keys. A Keyboard is just like a typewriter.
There are 102 different keys of different type on a keyboard. A Keyboard has four types of keys which are:

· Numeric Keys
· Alphanumeric keys
· Screen Navigation and Editing keys
· Function keys

Keyboard

Numeric keys:
This area of a keyboard contains numeric keys 0-9 and is used to enter numeric data into the computer. We can enter roll number, age, height, width and other numeric data through this area of the keyboard.

Alphanumeric keys:
This area of a keyboard contains alphabetic and numeric keys. In this area of keyboard characters A-Z, a-z and numbers 0-9 are included. We can enter alphanumeric data through these keys.

Screen Navigation and Editing Keys:
The screen navigation keys are used to move cursor on the monitor screen from one point to another. The editing keys are used for modifying text on the text window. The arrow keys are a part of this area.

Function Keys:
Function keys starts from F1 and end up on F12. There are total 12 function keys on a keyboard. Their function is different in different softwares.



Mouse:
Mouse is an input device for the beginners of computer. The people who are not familiar with the use of keyboard of computer can work easily on the computer with the help of mouse. It is always placed on a pad while working. A mouse may have two or three buttons.

Mouse

The mouse controls the position of the cursor and moves it around a computer. When we move the mouse on the pad, a small arrow like pointer moves on the screen. The mouse is mainly used in the Windows environment and other graphical software packages.
We can select any data by clicking the left mouse button once and to open any software or command, we have to double click the left mouse button quickly.

Joystick:
Joystick is another output device. It is just like a lever. It is used for moving things around on the screen. It is often used for playing games on the computer.

Joystick

A joystick has two or three buttons. By moving the lever L of joystick, we can move things and by clicking buttons, we can take any action.

Light Pen:
Light Pen is another input device. It is pen shaped. It is held in hand and can detect the presence of light with photoelectric cell at its front end.

Digital Scanner:
A digital scanner has become a very popular input device for a PC. When a scanner is attached to the computer, the scanner can read information of colour or black and white picture.
The scanner sends information to the computer, which we place on the glass surface of the scanner. The computer can store this information forever, or can send it across the world by using Internet in few minutes.

Scanner

The image scanner or digital scanner is a very useful device. It translates printed images into an electronic format that can be stored in a computer’s memory. You can then use software to organize or manipulate the electronic image. For example, if you have scanned a photo, you can use Adobe Photoshop, a graphics software to increase the contrast or to adjust the colours.

The Trackball:
A trackball is a pointing device that works like an upside-down mouse. You keep your thumb on the uncovered ball and your fingers on the buttons. To move the cursor around the screen, you roll the ball with your thumb. Because you don’t move the whole device. A trackball requires less space than a mouse, so when space is limited, a trackball can be a boon.

Trackball

Trackballs gained popularity with the advent of laptop computers, which are typically used on laps or on small work surfaces without room for a mouse.

The Trackpad:
The Trackpad is a stationary pointing device that many people find less tiring to use than a mouse or trackball. The movement of a finger across a small touch surface is translated into cursor movement on the computer screen. The touch-sensitive surface may be just 1.5 – 2 inches square, so the finger never has to move far. The size also makes it well suited for a notebook computer.

Microphone:
By using microphone, we can record our voice in a computer. This device is very easy to use and we can record our voice with music in the computer through this device.

Digital Camera:
Digital camera is used to draw photos. By using this input device images or photos are sent directly to PC instead of storing on a usual camera film.