Thursday, May 29, 2014

Reading Resistor Color Code Values

The electronic color code is used to indicate the values or ratings of electronic components, very common in resistors. Color bands were commonly used (especially on resistors) because they were easily printed on tiny components, decreasing construction costs.

A diagram of a resistor, with four color bands A, B, C, D from left to right A diagram of a 2.7 MΩ color-coded resistor.

To distinguish left from right there is a gap between the C and D bands.
  • band A is 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%)

Color Significant
figures
Multiplier Tolerance Temp. Coefficient (ppm/K)
Black 0 ×100 250 U
Brown 1 ×101 ±1% F 100 S
Red 2 ×102 ±2% G 50 R
Orange 3 ×103 15 P
Yellow 4 ×104 (±5%) 25 Q
Green 5 ×105 ±0.5% D 20 Z
Blue 6 ×106 ±0.25% C 10 Z
Violet 7 ×107 ±0.1% B 5 M
Gray 8 ×108 ±0.05% (±10%) A 1 K
White 9 ×109
Gold ×10-1 ±5% J
Silver ×10-2 ±10% K
None ±20% M

 Graphical Resistance Value Calculator: http://www.dannyg.com/examples/res2/resistor.htm

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