How to classify devices on the computer? Based on the connection location, the components on the computer are divided into internal and external devices. This article will introduce some external devices (peripherals) such as monitor, mouse, keyboard, printer.
1. Computer monitor
Monitor is an output device that display information in pictorial or textual form to help communication between user and computer. Types of monitors: CRT (Cathode Ray Tube), LED (Light Emitting Diode), LCD (Liquid Crystal Display), PLASMA, etc.
Some monitor manufacturers: SAMSUNG, IBM, DELL, LG,…
Specification of monitor:
Size of monitor: 15/17/19/21 inch and etc, measured along the main diagonal of monitor (aspect ratio 4:3, 16:9).
Resolution indicates number of horizontal pixels and number of vertical pixels. Pixel is a unit of image size, each pixel is a combination of 3 colors: Red, Green, Blue. Example: resolution 1024×768 means 1024 pixels horizontally and 768 pixels vertically.
Refresh rate: shows the number of frames in 1 second. Common refresh rate of monitor is 60, 70, 85Hz.
Response time is the time to completely transform a color of 1 pixel (in millisecond).
2. Computer mouse
Mouse helps to control and work with computers. Through mouse symbol with coordinates respectively on monitor, operations of computer will be controlled.
If computer mouse is classified according to the data transmission environment, there are wired mouse and wireless mouse. Wireless mouse send signals to the computer through a receiver / transmitter (Bluetooth, RFID (radio wave) or radio, infrared rays,…).
If computer mouse is classified according to principle of operation, there are trackball mouse and optical mouse.
Trackball mouse
The ball is placed at the bottom of the mouse, capable of contacting a flat surface, rolling freely in different directions. There are 2 spindles in contact with the ball. There are 2 light sensors to determine rotation direction and rotation speed. The electronic circuit decodes the signal and transmits coordinates of mouse to the mainboard.
Optical mouse
Optical mouse have a micro-capture device that continuously “captures” the surface where the user moves the mouse. Through the comparison between these images, the processor in the mouse will calculate the coordinates and transmit coordinates of mouse to the mainboard.
Connection port of mouse (Read more article Back Panel)
- Serial port
- PS/2
- USB
3. Computer keyboard
Computer keyboard is an input device that allows to enter data into the computer. In addition, the keyboard can replace the mouse to control the computer through key combinations. The keyboard has 4 main areas: function keys, character keys, number keys and control keys.
Connection port of keyboard (Read more article Back Panel)
- PS/2
- USB
4. Computer printer
A printer is a peripheral device which makes a persistent representation of graphics or text, usually on paper. There are many types of printers such as dot matrix printers, inkjet printers. Manufacturers: HP, Canon, Epson,…
