### device | electronic device | scanner:

Flatbed scanner
* are a practical and cost effective way to digitize images
  - reflective scanners useful for scanning both black and white and color prints
* can also record three dimensional objects of many sizes and shapes.
* consist of a flat glass plate onto which the document is placed.
* look like small copy machines, and there are similarities in how they work.

Laser scanner
* can also detect non-uniform material.
* have the best read rate of all types of scanners.
* track cars and send info about location to computers.

Optical scanner
* are a lateral move.
* have difficulty reading information that is bold, underlined, or italicized.
* measures the strength of the fluorescence of each sample spot.

Virus scanner
* Most virus scanners work by looking for virus 'signatures'.
* are an attempt to add security after the fact.
* basic tool for virus protection.

System clock
* Most system clocks drift a little bit each day.
* is an electronic device

Trackball
* are electronic devices
  - input devices
  - upside down mice, with the ball on top and several buttons
* can be worse because they rely on fine wrist and finger motion even more.
* utilize more hand movements than a mouse.

### device | electronic device:

Vacuum tube
* Some vacuum tubes are part of bridges
  - cellphones
  - circuits
  - clippers
  - modems
  - processors
  - receivers
  - stereos
  - telephones
  - separate weak electric current
* are basically like the the spark gap only there is no air in the gap, only a vacuum
  - characteristic of first-generation computers
  - electrical components
  - glass tubes with most of the air removed
  - made of glass
  - more like light bulbs with wires inside a bottle that's had all the air sucked out
  - wasteful of energy
* can amplify, mix, and separate weak electric currents.
* have essentially three basic types of emitters.
* operate primarily with high voltages that control the ion flows.

### device | electronic device | video display:

Alphanumeric display
* aids in identifying memorized frequencies.
* video display

### device | electronic device | video display:

Computer monitor
* All computer monitors display colors differently.
* Most computer monitors have a much higher resolution than a television picture tube
  - use progressive scanning because it significantly reduces flicker
* Some computer monitors have variable resolution which can affect the size of the browser windows.
* are closer to slides than prints in their ability to represent contrast.
* are located in desktops
  - tables
* are made of glass
  - plastic
  - notoriously inaccurate when it comes to true color reproductions
  - the worst offenders of all
* come in various sizes and resolutions.
* have a much higher resolution than most television monitors
  - non-linear response to the input voltage
  - restricted color space
  - low resolution, resulting in aliasing
* pose a special problem because they contain lead and cadmium.
* use additive color
  - typically noninterlaced video

Digital display
* are displays.
* video display

### device:

Elevator
* Many elevators therefore use buttons that are sensitive to the warmth of the human finger.
* Most elevators have emergency telephones.
* Some elevators are part of hospitals
  - observatories
  - skyscrapers
  - blow up because microscopic dust particles suspended in the air suddenly ignite
* are airfoils.
* are located in apartments
  - buildings
  - hotels
  - malls
  - mechanical devices
  - one of the most frequently used forms of transportation in the world
  - part of buildings
  - rooms
* are used for hoists
  - raises
* can act like giant pistons pushing smoke and fire to other parts of the building.
* have doors.
* includes bases
  - ceilings
  - elevator cars
  - floors
  - room light
  - sections
  - walls
* lifting device