Computer Hardware Safety Rules

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When installing/removing computer hardware and other peripherals:

  • Wear proper apparel. Avoid acrylic or wool sweaters when working with electronic parts. Do not wear loose fitting clothing, rings, bracelets etc.
  • Unplug all computer equipment and peripherals before opening any covering cases.
  • Keep your work area clean and well lit.
  • Check for damaged parts.
  • Do not force components into computer ports.
  • Use an anti-static wrist strap or discharge yourself by touching a grounded metal object such as a computer casing.
  • Power supplies produce several levels of voltage. Read the information on the power supply carefully and make sure that the power supply you are using is appropriate for the application.
  • Replace all cases or coverings after inspections or installations.
  • Check all circuits and installations with the instructor before power is applied.
  • Retain all screws during disassembly in containers such as film canisters for proper reassembly.
  • Electronic components should never become hot. Hot components means that there is a problem with the circuit. Disconnect any power immediately.

The most important safety rule of all: Always Be Careful! (ABC)

(from ICE4M Supplemental Profile Unit 1, Appendix 1.1.1)

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Resistor Colour Code

Color Digit value Multiplier Multiplied Out Tolerance
Black 0 100 1
Brown 1 101 10
Red 2 102 100
Orange 3 103 1,000
Yellow 4 104 10000
Green 5 105 100,000
Blue 6 106 1,000,000
Violet 7 107 10,000,000
Gray 8 108 100,000,000
White 9 109 1,000,000,000
Gold ±5%
Silver ±10%

See also http://www.eeweb.com/toolbox/4-band-resistor-calculator for an online resistance calculator.