Peripherals are hardware input and output devices that are not essential to the core functions of the PC, but that can expand its performance ability. Commonly used peripherals include mice, keyboards, webcams, microphones, monitors, speakers, projectors, and printers. An input device is a hardware device that the user interacts with to send data signals to the motherboard where the CPU processes it for output. Input devices include mice and keyboards. Output devices are hardware devices which relay the information the CPU processes to the user via monitors, speakers, and other output devices.
The mouse was invented by Douglas Engelbart in 1963. Engelbart was a researcher working at the Stanford Research Institute, who was searching for alternative ways for humans to interact with computers. He pictured a pointing device that would react on the screen in response to the hand movements of the user. This device would be more intuitive and efficient than a keyboard, however, it would still work in tandem with the keyboard to input information. The mouse was introduced to the public in 1968 in a San Francisco computer conference, but was not widely used until the 1980's when personal computers became more of a norm.
A commonly used mouse is the electromechanical mouse. The electromechanical mouse has a rubber ball on the underside which transmits electrical signals to the computer. The signal is transmitted through a cable which connects the mouse to one of the computer's ports, which are entry and exit points for the information exchanged between the computer and the peripherals. There are two rollers in the mouse, which are touched by the rubber ball when the mouse is moved. The rollers are connected to a wheel which has two small metal bars called contact points connected to it. The wheel (known as an encoder) spins when the rollers spin and the contact points touch the contact bars which then transmit the signal through the cable.
Other examples include optomechanical, optical, and laser versions of the mouse.
Keyboards use microprocessors also known as encoders to transmit the information to the computer. The encoder has a system of signals which relies on the users direction. When a user presses a key, a code specific to that key is generated by the encoder which is read with the help of the system of rows and columns, forming a grid. After the key is pressed, the encoder makes a connection on this grid, creating a code. This special code, which the encoder passes to the computer, is known as a scanning code. The computer takes the scanning code and turns it into a binary code which can then be displayed on a monitor for the user to see.
These are just a couple of examples of peripherals, but there are numerous other devices that can expand your computer's capacities.
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"Peripherals." World of Computer Science, Gale, 2007. Gale In Context: Biography, link.gale.com/apps/doc/CV2424500456/BIC?u=rock21695&sid=bookmark-BIC&xid=9080e214. Accessed 8 Feb. 2022.