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Encyclopedia > Electronic color code

The electronic color code discussed here is used to indicate the values or ratings of electronic components, very commonly for resistors, but also for capacitors, inductors, and others. A separate code, the 25-pair color code, is used to identify wires in a cable or bundle. Resistor symbols (non-European) Resistor symbols (Europe, IEC) Axial-lead resistors on tape. ... Capacitors: SMD ceramic at top left; SMD tantalum at bottom left; through-hole tantalum at top right; through-hole electrolytic at bottom right. ... An inductor is a passive electrical device employed in electrical circuits for its property of inductance. ... The 25 pair color code is a color code used to identify individual conductors in a kind of electrical communication wiring known as twisted pair cables. ...


The electronic color code was developed in the early 1920's by the Radio Manufacturer's Association, now part of Electronic Industries Alliance and codified as EIA-RS-279. The international standard IEC-60757 is equivalent. The Electronic Industries Alliance (EIA, until 1997 Electronic Industries Association) is a trade organization for electronics manufacturers in the United States. ... The International Electrotechnical Commission (IEC) is an international standards organization dealing with electrical, electronic and related technologies. ...


The advantage of color coding (over printed text) on physically small components is the inherent increase in marking area, which makes the values easier to read without magnification. Color coded markings are also more resistant to abrasion.


A significant drawback, on the other hand, is color degradation due to aging, oxidation and overheating. In the days of classical chassis televisions, for example, overheated resistors would change their color bands, making it virtually impossible to distinguish brown from red from orange, except by circuit analysis and deduction. This could mean the difference between a 330 Ω, 3.3 kΩ or 33 kΩ resistor respectively (a factor of 100). An overheated 33 kΩ resistor often looked like 330 Ω. Dirt, unusual lighting, and color blindness can also make it difficult to read color codes.

Contents

Other schemes

Color-coding of this form is becoming rarer. In newer equipment, most passive components come in surface mount packages. Many of these packages are unlabeled, and those that are are normally labeled with alphanumeric codes, not colors. In one popular marking method, the manufacturer prints 3 digits on components: 2 value digits followed by the power of ten multiplier. Thus the value of a resistor marked 472 is 4,700 Ω and a capacitor marked 104 is 100 nF (100,000 pF). This can be confusing; a resistor marked 472 might seem to be a 472 Ω unit, and we must rely upon experience to interpret markings. Another way is to use the "kilo-" or "mega-" prefixes in place of the decimal point: Surface-mount components on a keydrives circuit board Surface mount technology (SMT) is a method for constructing electronic circuits in which the components are mounted directly onto the surface of printed circuit boards (PCBs). ... Kilo (symbol: k) is a prefix in the SI system denoting 103 or 1,000. ... Mega (symbol M) is a SI prefix in the SI system of units denoting a factor of 106, i. ...

1K2 = 1.2 kΩ = 1,200 Ω
4M7 = 4.7 MΩ = 4,700,000 Ω

For 1% resistors, a three-digit alphanumeric code is sometimes used, which is not obviously related to the value at all. For instance, a resistor marked 68C is 499(68) × 100(C) = 49,900 Ω.


It is sometimes not obvious whether a color coded component is a resistor, capacitor, or inductor, and this may be deduced by knowledge of its circuit function, physical shape or by measurement (capacitors have nearly infinite resistance; unfortunately, so do faulty open-circuit resistors and inductors).


Resistors, capacitors and inductors

A diagram of a resistor, with four color bands A, B, C, D from left to right Image File history File links Resistor color bands, drawn by myself File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...


Resistor values are always coded in ohms, capacitors in picofarads (pF), inductors in microhenries (µH), and transformers in volts. A multimeter can be used to measure resistance in ohms. ... Capacitors: SMD ceramic at top left; SMD tantalum at bottom left; through-hole tantalum at top right; through-hole electrolytic at bottom right. ... Examples of various types of capacitors. ... An inductor is a passive electrical device employed in electrical circuits for its property of inductance. ... An inductor. ... Three-phase pole-mounted step-down transformer. ... Josephson junction array chip developed by NIST as a standard volt. ...

  • band A is first significant figure of component value
  • band B is the second significant figure
  • band C is the decimal multiplier
  • band D if present, indicates tolerance of value in percent (no color means 20%)

For example, a resistor with bands of yellow, violet, red, and gold will have 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%.


Resistors manufactured for military use may also include a fifth band which indicates component failure rate (reliability); refer to MIL-HDBK-199 for further details. Reliability concerns quality or consistency. ... A United States Defense Standard, often called a military standard, MIL-STD, or MIL-SPEC, is used to help achieve standardization objectives by the U.S. Department of Defense. ...


Tight tolerance resistors may have three bands for significant figures rather than two, and/or an additional band indicating temperature coefficient, in units of ppm/K. The temperature coefficient is the relative change of a physical property when the temperature is changed by 1 K (kelvin). ... Parts per million (ppm) is a measure of concentration that is used where low levels of concentration are significant. ... The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. ...


All coded components will have at least two value bands and a multiplier; other bands are optional (italicised below).


The Standard EIA Color Code Table per EIA-RS-279 is as follows: The Electronic Industries Alliance (EIA, until 1997 Electronic Industries Association) is a trade organization for electronics manufacturers in the United States. ...

Color Value digit 1 Value digit 2 Value digit 3 Multiplier Tolerance Temp. Coefficient
Black 0 0 0 ×100    
Brown 1 1 1 ×101 ±1% (F) 100 ppm/K
Red 2 2 2 ×102 ±2% (G) 50 ppm/K
Orange 3 3 3 ×103   15 ppm/K
Yellow 4 4 4 ×104   25 ppm/K
Green 5 5 5 ×105 ±0.5% (D)  
Blue 6 6 6 ×106 ±0.25% (C)  
Violet 7 7 7 ×107 ±0.1% (B)  
Gray 8 8 8 ×108 ±0.05% (A)  
White 9 9 9 ×109    
Gold       ×0.1 ±5% (J)  
Silver       ×0.01 ±10% (K)  
None         ±20% (M)  

Black cat, thought by some to cause bad luck Black is the shade of objects that do not reflect light in any part of the visible spectrum. ... Brown, when used as a general term, is a color which is a dark orange, red or rose, of very low intensity. ... Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 625–750 nm. ... The orange, a fruit from which the modern name of the orange colour comes. ... A yellow Tulip. ... Mossy, green fountain in Wattens, Austria. ... YOU SUCK!!!!! ... Violet (named after the flower violet) is used in two senses: first, referring to the color of light at the short-wavelength end of the visible spectrum, approximately 380–420 nanometres (this is a spectral color). ... Gray or grey is a color seen commonly in nature. ... This article is about the color. ... Gold is a shade of the color yellow closest to that of gold metal. ... Silver is the metallic shade of the color gray closest to that of polished silver. ...

Mnemonics

A useful mnemonic for remembering the first ten color codes matches the first letter of the color code, by order of increasing magnitude. There are many variations: Wikiquote has a collection of quotations related to: English mnemonics A mnemonic (pronounced in RP, [nɪmɑnɪk] in GA) is a memory aid, and most serve an educational purpose. ... In science, a magnitude is the numerical size of something: see orders of magnitude. ...

  • Bad Beer Rots Our Young Guts But Vodka Goes Well
  • Bright Boys Rave Over Young Girls But Veto Getting Wed
  • B. B. R O Y of Great Britain has a Very Good Wife
  • Big Boys Race Our Young Girls But Violet Generally Wins
  • Better Be Right Or Your Great Big Venture Goes West
  • Black Beauty Ran Over Yellow Grass By Violent Grey Waters
  • Bad Boys Race Over Yonder Green But Victory Goes Wanting
  • Black Birds Roam Over Your Garden But Vultures Go West

The word "Bad" in the first mnemonic and "Bright" in the second mnemonic are often replaced with the word "Black" since black comes before brown in the color code. While the second mnemonic is certainly the most offensive of these, all except the third lack a sobriety that might be desirable, especially in a teaching context. A more staid memory aide uses the fact that the central part of the code follows the color spectrum, without the i for indigo. That is, The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ...

The most common variation of the mnemonic for the EIA color code generally doesn't stay posted on this page for long due to its choice of words which is more offensive to many today than when it was originated (mid 1920's). Refer to the discussion for details. Wikiquote has a collection of quotations related to: English mnemonics#Science Roy G. Biv is a popular mnemonic device used for memorizing the traditional optical spectrum: Red Orange Yellow Green Blue Indigo Violet The colors are arranged in the order of decreasing wavelengths, with red being about 700 nanometers and...


Besides the ten colors of the main value code, the tolerance code is often remembered as "for Gold or Silver" appended to the more offensive mnemonic, or "Get Some Now" where Now refers to none for 20%.


If it is difficult to recall that black comes before brown in the color code, it may be helpful to use the position of white at the end of the color code as a key to remember that black (and not brown) is at the beginning.


Other languages have other mnemonics for this color code. A rough translation of the French is "Don't eat anything or I'll beat you violently, big animal."


Examples


From top to bottom: Image File history File linksMetadata No higher resolution available. ...

  • Green-Blue-Black-Black-Brown
    • 560 Ω ± 1%
  • Red-Red-Orange-Gold
    • 22,000 Ω ± 5%
  • Yellow-Violet-Brown-Gold
    • 470 Ω ± 5%
  • Blue-Gray-Black-Gold
    • 68 Ω ± 5%

Note: The sizes of the resistors depend only on the power they can dissipate, and do not affect their value.


See also

The 25 pair color code is a color code used to identify individual conductors in a kind of electrical communication wiring known as twisted pair cables. ... A color code is a system for displaying information by using different colors. ...

External links


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