Input and Output Devices
A computer activity consists of input processing, storage and output. There are four stages to the information processing cycle: Input, process, output and storage. The input devices send information into CPU where processing is done and accordingly the output is displayed. An input device includes a keyboard, a terminal, a touch screen, a mouse, a scanner, etc. An optical mouse has a small, red diode light emitting diode that bounces the light off that surface onto a CMOS sensor. The computer moves the cursor on the screen based on the coordinates received from the mouse. When a person speaks into the microphone, an analog sound wave is picked up by a microphone and sent to the sound card. The sound card digitises audio input into zeros and ones with the help of an Analog to Digital converter. During the playback, the sound is converted from digital to analog signals using the Digital to Analog Converted. These signals are then passed to a speaker that vibrate the speaker cone that moves the air to create sound waves and analog noise. Hardware is any physical part of your computer that you can touch and see, such as computer monitor or keyboard.