input and output devices

output device

An component that allows information to come out of the computer . The output can be seen or heard . output devices include speakers , headphones ,monitor , printer ,plotter ,and speech synthesizer.

input device

An computer part that allows the user to enter information into the computer. input devices include the keyboard, mouse, scanner , microphone, scanner, joystick ,trackball ,touchpad , touchscreen , and light pen .

keyboard

An computers main text input device . The following contains letters, numbers , standard function keys , cursor movement (arrow) keys , formatting keys ,and other manufacturer-customized keys.

Printer

An device that accepts text and graphic output from a computer and transfers the information to paper .

Scanner

An device that can read text or pictures printed on paper and translate the information into a form the computer can use . This device serves as the computers eyes.

Headphones

An small speaker that is placed over or into the ear . this device is used to listen to music privately.

how does the computer know which letter is being pressed ?

The keyboard is made up of wires that connect together which causes an electrical impulse when the wires touch that sends an message to an computer chip inside the keyboard to locate the where the wires met . Than an character map notifies the computer which letter is being pressed

what are the two types of printers and what do they do ?

The two types of printers are an ink jet and laser jet an ink jet sprays ink from an ink cartridge at very close range to the paper as it rolls by. an laser jet uses a laser beam reflected from a mirror to attract in (called toner) to selected paper areas as a sheet rolls over a drum .

Speakers

This device is used to hear sound from the computer . the volume is controlled by turning the knob

Microphone

This device is used to record or transmit sound made by a person's voice when they talk or sing . the voice maybe recorded in order to make music or to create a narration.

Monitor

This is a essential part of a computer system that displays text and graphics generated by a computer. monitors display information in many colors and are the best compared with color televisions

Compare how each of these input devices work using an organizational chart

an joystick is a lever that moves in all directions and controls the movement of a pointer or some other symbol. an trackball contains a ball which , when rotated, changes the position of the pointer on the screen . an touchpad is used to position the mouse pointer . it reacts to the touch of a finger as it is moved across the pad . an touchscreen is a special monitor that is touched with the finger to make selections. this device is often used in a kiosk or an bank machine.

how does these two types of mice work ?

an optical mouse is uses an tiny camera that takes over a thousand pictures per second to determine how to move the mouse pointer . an mechanical mouse use a ball and rollers to determine how to move the mouse pointer . when the mouse is used along the mouse pad , it causes a ball inside the mouse .

mouse

an small device that a person pushes across a desk surface to position the mouse pointer . the buttons on top of the device is used to perform tasks such as making an selection , changing the view in a window , moving an item on the screen , or resizing an object .

what are the two types of mice ?

optical mouse and mechanical mouse

how does the keys "bounce" back up after being pressed ?

underneath each key is a piece of material called a dome . when a key is being pressed , a plunger on the bottom of the key pushes down against the dome . when the key is released , the dome springs back to its original shape , forcing the key back up its at rest position .