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L9, Resistor Color Coding

To distinguish left from right there is a gap between the C, G and D bands.

  • band A is the first significant figure of component value (left side)

  • band B is the second significant figure (some precision resistors have a third significant figure, and thus five bands).

  • band C is the decimal multiplier

  • band D if present, indicates tolerance of value in percent (no band means 20%)

For example, a resistor with bands of yellow, violet, red, and gold has first digit 4 (yellow in table below), second digit 7 (violet), followed by 2 (red) zeros: 4,700 ohms. Gold signifies that the tolerance is ±5%, so the real resistance could lie anywhere between 4,465 and 4,935 ohms.

Tips for reading resistor codes-

• The reading direction might not always be clear. Sometimes the increased space between band 3 and 4 give away the reading direction. Also, the first band is usually the closest to a lead. A gold or silver band (the tolerance) is always the last band.

• It is a good practice to check the manufacturer’s documentation to be sure about the used coding system. Even better is to measure the resistance with a multi-meter. In some case this might even be the only way to figure out the resistance; for example, when the color bands are burnt off.

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