Chapter Three

Peripherals and NetworkingPart I: Peripheral Devices

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Strata Objectives Covered

1.2 (1.2 FCO-11 U.K.) Demonstrate the proper use of the following devices

– Monitors

1.3 (1.2 FCO-11 U.K.) Demonstrate the ability to set up a basic PC workstation

– Identify differences between connector types: DVI, VGA, HDMI; Bluetooth and Wireless; Network connectors; 3.5mm audio jack

– Monitor types– Printer (USB, wireless, networked)

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Strata Objectives Covered (continued)

1.4 Explain the characteristics and functions of peripheral devices

– Digital camera– Speaker– Tuner– Microphone– Printer/scanner

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What is a Peripheral?

• A device that is external to the main body of the computer

• A device that isn’t essential to the computer’s functioning

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The Printing Process

1. Receive data from the PC

2. Store the data in RAM

3. Convert the data to print instructions

4. Feed the paper

5. Store and dispense ink and toner

6. Transfer the image to the paper

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Differences Between Printers

• Printer type (inkjet, laser)• Costs (initial, consumables)• Output quality and resolution• Photo printing capability• Speed• Paper tray• Interfaces• Multi-function

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Inkjet Printers

• Squirt liquid ink onto paper• Between 21 and 256 nozzles for

each of the four colors• Cyan, yellow, magenta, and black• Some photo printers have 6 or 8

cartridges

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Inkjet Technologies

• Thermal (bubble jet): heat the ink, creating vapor bubbles that force the ink out. This creates a vacuum in the cartridge which draws more ink into the nozzles.

• Piezoelectric: moves the ink with electricity instead of heat. Nozzles contain piezoelectric crystals that change their shape when electricity is applied to them and force out the ink

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Laser Printer

• Drum (large cylinder) carries high negative electrical charge

• Laser partially neutralizes the charge on areas of the drum

• Toner clings to the areas of lesser charge

• Toner jumps off onto positively charged paper

• Fuser melts toner onto the paper

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Printer Interfaces

• USB• Legacy parallel• Network• Bluetooth

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Monitors

• Liquid Crystal Display (LCD)– Flat, thin, low

power consumption

– Light passes through filters and liquid crystals to create the image

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Monitors

• Cathode Ray Tube (CRT)– Large, boxy monitor, old technology– Vacuum tube that uses electron guns to

light up phosphors on the inside of the monitor glass to form the image

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Monitor Connectors

• Video Graphics Array (VGA)– Older standard– Analog

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Monitor Connectors

• Digital Video Interface (DVI)– Newer standard– Can be digital or analog (mostly digital)

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Monitor Connectors

• High-Definition Multimedia Interface (HDMI)– Used for TVs and home theater– Less frequently used for computers– Digital

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Sound System

• Sound card (or sound adapter built into motherboard)

• Speakers• Microphone• Jacks for other external devices,

such as headphones

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Speakers

• Amplification• Shielding• Frequency range• Analog vs. digital: if digital, use

special digital output port from sound card

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Microphone

• May be built into notebook computer• Frequency response• Stereo vs. mono• Unidirectional vs. omnidirectional• Headset vs. desktop• Analog vs. digital

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Scanner

• Digitizes flat hard-copy image• Uses charge-coupled device (CCD)

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Scanner

• Quality measured in dots per inch (DPI)– Horizontal DPI: also called x-direction

sampling rate– Vertical DPI: also called y-direction

sampling rate

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Digital Camera

• Stores camera images to digital media, such as flash RAM

• Transfers photos to PC, printer, or other digital device

• Resolution measured in megapixels (millions of pixels)

• Example: 10 megapixels = 3872 wide by 2592 high

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Digital Camera

• Camera size• Zoom• Storage medium• PC interface• Manual adjustments• Delay between pictures• Video capture

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Web cams

• Low-resolution video camera that feeds its images directly into a computer or network

• Must have a connection to a computer to operate

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TV Tuners

• Peripheral device that enables a computer to receive, display, and store TV broadcasts

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