Besides personal computers consisting of a main processing unit, it usually includes the keyboard, mouse, memory or RAM, hard disk, dvd drive, monitor to make it functional.  You can usually purchase the whole computer system with the processing unit, keyboard, mouse, memory, hard disk, dvd drive, monitor and other component, unless you would like to buy each component separately.  Online or walk-in stores are great places to purchase a personal computer for home or business use.  Let us discuss a few basic components in the following sections.

Keyboard is an important component for a computer system.  Users like you will need a device such as a keyboard to enter your words and commands for the computer.  It is a input device you will use to answer questions from a website while ordering an item, creating an article or essay, to enter registration information to a new website.  Each key represent an alphabet, number, function, spacebar, alt, ctrl, and action keys like Insert, Delete, Home, Page Up, Page Down, Home, End, arrows and other keys. 

Each time you type a key on the keyboard, it sends a signal through the circuit underneath called Key Matrix Circuit to the computer.  The connection from a keyboard to the computer is accomplished with a cable to a PS/2 or USB connection.  There are many useful tips about computers at http://www.fidetips.com/computer.

Another major component is the mouse, which is mostly used for clicking a button, checkbox, option box, or to navigate around the screen on the monitor.  It is very useful if you are drawing on the screen, like painting a picture or drawing a flowchart.  There are basically ball mouse, optical mouse, and laser mouse types.  A ball mouse is a mouse with a round ball under the casing, moving the mouse on a mouse pad will rotate the ball and then send the signal to the computer for the navigation. 

An optical or laser mouse both use optical to send signal to the computer, the difference is an optical mouse uses light-emitting diode or photo diode to detect the movement, while laser mouse uses infrared laser diode to sense the motions.  Diodes are an electronics component that generally emits light.  The connection from a keyboard to the computer is achieved with a cable to the RS-232C, PS/2 or USB connection on the computer.

Memory components such as Random-Access memory or RAM or hard disk are essential for the computer storages.  RAM is basically used for temporary storage of data, and the data will be erased after exiting a software, rebooting or turning off the computer.  The large size the RAM the higher performance and faster the computer will work, because the computer can do most of the work on it without copy data back and forth from the hard disk.  Hard disk is a permanent storage device for the computer, saved data will stay there until they are erased.  Again, the higher the access and rotation speed of the hard disk will improve the overall performance for the computer system.  DVD or Digital Video Disc drive is another component that is important for you to install software or store data to a cd or dvd disk.  It can store gigabytes of data and you will also look for the higher speed for its performance.