An electronic color code or electronic colour code (see

spelling differences Despite the various English dialects spoken from country to country and within different regions of the same country, there are only slight regional variations in English orthography, the two most notable variations being British and American ...

) is used to indicate the values or ratings of electronic components, usually for

resistor A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active el ...

s, but also for

capacitor A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of ...

inductor An inductor, also called a coil, choke, or reactor, is a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. An inductor typically consists of an insulated wire wound into a c ...

diode A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other. A diode ...

s and others. A separate code, the 25-pair color code, is used to identify wires in some

telecommunication Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...

s cables. Different codes are used for wire leads on devices such as transformers or in building wiring.

History

Before industry standards were established, each manufacturer used their own unique system for color coding or marking their components. In the 1920s, the RMA resistor color code was developed by the

Radio Manufacturers Association The Electronic Industries Alliance (EIA; until 1997 Electronic Industries Association) was an American standards and trade organization composed as an alliance of trade associations for electronics manufacturers in the United States. They devel ...

(RMA) as a fixed resistor coloring code marking. In 1930, the first

radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...

s with RMA color-coded resistors were built. Over many decades, as the organization name changed (RMA, RTMA, RETMA,

EIA Eia or EIA may refer to: Medicine * Enzyme immunoassay * Equine infectious anemia * Exercise-induced anaphylaxis * Exercise-induced asthma * External iliac artery Transport * Edmonton International Airport, in Alberta, Canada * Erbil Internation ...

) so was the name of the code. Though known most recently as EIA color code, the four name variations are found in books, magazines, catalogs, and other documents over more than years. In 1952, it was standardized in IEC 62:1952 by the

International Electrotechnical Commission The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and r ...

(IEC) and since 1963 also published as EIA RS-279. Originally only meant to be used for fixed resistors, the color code was extended to also cover capacitors with IEC 62:1968. The code was adopted by many national standards like DIN 40825 (1973), BS 1852 (1974) and IS 8186 (1976). The current international standard defining marking codes for resistors and capacitors is IEC 60062:2016. In addition to the color code, these standards define a letter and digit code named

RKM code The RKM code, also referred to as "letter and numeral code for resistance and capacitance values and tolerances", "letter and digit code for resistance and capacitance values and tolerances", or informally as "R notation" is a notation to specif ...

for resistors and capacitors. Color bands were used because they were easily and cheaply printed on tiny components. However, there were drawbacks, especially for

color blind Color blindness or color vision deficiency (CVD) is the decreased ability to see color or differences in color. It can impair tasks such as selecting ripe fruit, choosing clothing, and reading traffic lights. Color blindness may make some aca ...

people. Overheating of a component or dirt accumulation may make it impossible to distinguish brown from red or orange. Advances in printing technology have now made printed numbers more practical on small components. The values of components in surface mount packages are marked with printed alphanumeric codes instead of a color code.

Resistors

Color band system

To distinguish left from right there is a gap between the C and D bands: In the above example, a resistor with bands of red, violet, green, and gold has first digit 2 (red; see table below), second digit 7 (violet), followed by 5 (green) zeroes: . Gold signifies that the tolerance is ±5%. Precision resistors may be marked with a five band system, to include three significant digits, a power of 10 multiplier (number of trailing zeroes, and a tolerance band. An extra-wide first band indicates a wire-wound resistor. Resistor Color Code

Resistors manufactured for military use may also include a fifth band which indicates component failure rate (

reliability Reliability, reliable, or unreliable may refer to: Science, technology, and mathematics Computing * Data reliability (disambiguation), a property of some disk arrays in computer storage * High availability * Reliability (computer networking), a ...

); refer to MIL-HDBK-199 for further details. Tight tolerance resistors may have three bands for significant figures rather than two, or an additional band indicating

temperature coefficient of resistance A temperature coefficient describes the relative change of a physical property that is associated with a given change in temperature. For a property ''R'' that changes when the temperature changes by ''dT'', the temperature coefficient α is def ...

(TCR), in units of ppm/ K. All coded components have at least two value bands and a multiplier; other bands are optional. The standard color code per IEC 60062:2016 is as follows: Resistors use various

E series of preferred numbers The E series is a system of preferred numbers (also called preferred values) derived for use in electronic components. It consists of the E3, E6, E12, E24, E48, E96 and E192 series, where the number after the 'E' designates the quantity of ...

for their specific values, which are determined by their tolerance. These values repeat for every decade of magnitude: ... 0.68, 6.8, 68, 680, ... For resistors of 20% tolerance the E6 series, with six values: 10, 15, 22, 33, 47, 68, then 100, 150, ... is used; each value is approximately the previous value multiplied by . For 10% tolerance resistors the E12 series, with as multiplier, is used; similar schemes up to E192, for 0.5% or tighter tolerance are used. The separation between the values is related to the tolerance so that adjacent values at the extremes of tolerance approximately just overlap; for example, in the E6 series is 12, while is also 12. Zero ohm resistors, marked with a single black band, are lengths of wire wrapped in a resistor-like body which can be mounted on a

printed-circuit board A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a laminated sandwich struc ...

(PCB) by automatic component-insertion equipment. They are typically used on PCBs as insulating "bridges" where two tracks would otherwise cross, or as soldered-in

jumper Jumper or Jumpers may refer to: Clothing *Jumper (sweater), a long-sleeve article of clothing; also called a top, pullover, or sweater **A waist-length top garment of dense wool, part of the Royal Navy uniform and the uniform of the United State ...

wires for setting configurations.

Body-end-dot system

The "body-end-dot" or "body-tip-spot" system was used for cylindrical composition resistors sometimes still found in very old equipment (built before the Second World War); the first band was given by the body color, the second band by the color of one end of the resistor, and the multiplier by a dot or band around the middle of the resistor. The other end of the resistor was in the body color, silver, or gold for 20%, 10%, 5% tolerance (tighter tolerances were not routinely used).

Examples

From top to bottom: * Green, blue, black, black, brown ** 560 ohms ±1% * Red, red, orange, gold ** ±5% * Yellow, violet, brown, gold ** 470 ohms ±5% * Blue, grey, black, gold ** 68 ohms ±5% The physical size of a resistor is indicative of the

power Power most often refers to: * Power (physics), meaning "rate of doing work" ** Engine power, the power put out by an engine ** Electric power * Power (social and political), the ability to influence people or events ** Abusive power Power may a ...

it can dissipate. There is an important difference between the use of three and of four bands to indicate resistance. The same resistance is encoded by: *Red, red, ''orange'' = ''22'' followed by ''3'' zeroes = (excluding default, silver, or gold tolerance) *Red, red, ''black'', ''red'' = ''220'' followed by ''2'' zeroes = (excluding brown or other band for tolerance)

Mnemonics

Useful

mnemonic A mnemonic ( ) device, or memory device, is any learning technique that aids information retention or retrieval (remembering) in the human memory for better understanding. Mnemonics make use of elaborative encoding, retrieval cues, and imag ...

s have been created to make it easier to remember the numeric order of resistor color bands. The following example includes the tolerance codes gold, silver, and none: * Bad Beer Rots Out Your Guts But Vodka Goes Well – Get Some Now. * Betty Brown Runs Over Your Garden But Violet Gingerly Walks. * Bad Bears Raid Our Yummy Grub But Veto Grey Waffles. * BB ROY from Great Britain has a Very Good Wife. The colors are sorted with ascending values in the order of the

visible light spectrum The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called ''visible light'' or simply light. A typical human eye will respond to wav ...

to make them easy to remember and to reduce the significance of possible read errors due to color shifts and fading over time: red (2), orange (3), yellow (4), green (5), blue (6), violet (7). Black (0) has no energy, brown (1) has a little more, white (9) has everything and grey (8) is like white, but less intense.

Capacitors

Capacitors may be marked with 4 or more colored bands or dots. The colors encode the first and second most significant digits of the value in picofarads, and the third color the decimal multiplier. Additional bands have meanings which may vary from one type to another. Low-tolerance capacitors may begin with the first 3 (rather than 2) digits of the value. It is usually, but not always, possible to work out what scheme is used by the particular colors used. Cylindrical capacitors marked with bands may look like resistors. Extra bands on ceramic capacitors identify the voltage rating class and temperature coefficient characteristics. A broad black band was applied to some tubular paper capacitors to indicate the end that had the outer electrode; this allowed this end to be connected to chassis ground to provide some shielding against hum and noise pickup.

Polyester Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include natural ...

film A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere ...

and "gum drop"

tantalum electrolytic capacitor A tantalum electrolytic capacitor is an electrolytic capacitor, a passive component of electronic circuits. It consists of a pellet of porous tantalum metal as an anode, covered by an insulating oxide layer that forms the dielectric, surrounded ...

s may also be color-coded to give the value, working voltage and tolerance.

Postage stamp capacitors and war standard coding

Capacitors of the rectangular "postage stamp" form made for military use during World War II used ''

American War Standard American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, pe ...

'' (AWS) or ''

Joint Army-Navy The Joint Electronics Type Designation System (JETDS), which was previously known as the Joint Army-Navy Nomenclature System (AN System. JAN) and the Joint Communications-Electronics Nomenclature System, is a method developed by the U.S. War Depa ...

'' (JAN) coding in six dots stamped on the capacitor. An arrow on the top row of dots pointed to the right, indicating the reading order. From left to right the top dots were: either black, indicating JAN

mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is ...

, or silver, indicating AWS paper; first significant digit; and second significant digit. The bottom three dots indicated temperature characteristic, tolerance, and decimal multiplier. The characteristic was black for , brown for ±500, red for ±200, orange for ±100, yellow for −20 to +100 ppm/°C, and green for 0 to +70 ppm/°C. A similar six-dot code by EIA had the top row as first, second and third significant digits and the bottom row as voltage rating (in hundreds of volts; no color indicated 500 volts), tolerance, and multiplier. A three-dot EIA code was used for 500 volt 20% tolerance capacitors, and the dots signified first and second significant digits and the multiplier. Such capacitors were common in

vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. The type kn ...

equipment and in surplus for a generation after the war but are unavailable now.

Inductors

Standards IEC 60062 / EN 60062 do not define a color code for

s, but manufacturers of small inductors use the resistor color code, typically encoding inductance in microhenries. A white tolerance ring is used by

TDK is a Japanese multinational electronics corporation that manufactures electronic components and recording and data-storage media. Its motto is "Contribute to culture and industry through creativity". "TDK" is an initialism of the original Ja ...

to indicate custom specifications.

Diodes

The part number for small

JEDEC The JEDEC Solid State Technology Association is an independent semiconductor engineering trade organization and standardization body headquartered in Arlington County, Virginia, United States. JEDEC has over 300 members, including some of the w ...

"1N"-coded diodes—in the form "1N4148"—is sometimes encoded as three or four rings in the standard color code, omitting the "1N" prefix. The 1N4148 would then be coded as yellow (4), brown (1), yellow (4), grey (8).

Wire

Transformer

Power

transformer A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer' ...

s used in North American vacuum-tube equipment were often color-coded to identify the leads. Black was the primary connection, red secondary for the B+ (plate voltage), red with a yellow tracer was the

center tap In electronics, a center tap (CT) is a contact made to a point halfway along a winding of a transformer or inductor, or along the element of a resistor or a potentiometer. Taps are sometimes used on inductors for the coupling of signals, and ...

for the B+ full-wave rectifier winding, green or brown was the heater voltage for all tubes, yellow was the filament voltage for the rectifier tube (often a different voltage than other tube heaters). Two wires of each color were provided for each circuit, and phasing was not identified by the color code. Audio transformers for vacuum tube equipment were coded blue for the finishing lead of the primary, red for the B+ lead of the primary, brown for a primary center tap, green for the finishing lead of the secondary, black for grid lead of the secondary, and yellow for a tapped secondary. Each lead had a different color since relative polarity or phase was more important for these transformers. Intermediate-frequency tuned transformers were coded blue and red for the primary and green and black for the secondary.

Other

Wires may be color-coded to identify their function, voltage class, polarity, phase or to identify the circuit in which they are used. The insulation of the wire may be solidly colored, or where more combinations are needed, one or two tracer stripes may be added. Some wiring color codes are set by national regulations, but often a color code is specific to a manufacturer or industry.

Building wiring Electrical wiring is an electrical installation of cabling and associated devices such as switches, distribution boards, sockets, and light fittings in a structure. Wiring is subject to safety standards for design and installation. Allowable ...

under the US National Electrical Code and the Canadian Electrical Code is identified by colors to show energized and neutral conductors, grounding conductors and to identify phases. Other color codes are used in the UK and other areas to identify building wiring or flexible cable wiring. Mains electrical wiring, both in a building and on equipment was once usually red for live, black for neutral, and green for earth, but this was changed as it was a hazard for color-blind people, who might confuse red and green; different countries use different conventions. Red and black are frequently used for positive and negative of battery or other single-voltage DC wiring.

Thermocouple A thermocouple, also known as a "thermoelectrical thermometer", is an electrical device consisting of two dissimilar electrical conductors forming an electrical junction. A thermocouple produces a temperature-dependent voltage as a result of th ...

wires and extension cables are identified by color code for the type of thermocouple; interchanging thermocouples with unsuitable extension wires destroys the accuracy of the measurement. Automotive wiring is color-coded but standards vary by manufacturer; differing SAE and DIN standards exist. Modern

personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...

peripheral cables and connectors are

color-coded A color code is a system for displaying information by using different colors. The earliest examples of color codes in use are for long-distance communication by use of flags, as in semaphore communication. The United Kingdom adopted a color c ...

to simplify connection of speakers, microphones, mice, keyboards and other peripherals, usually according to coloring schemes following recommendations such as

PC System Design Guide The PC System Design Guide (also known as the PC-97, PC-98, PC-99, or PC 2001 specification) is a series of hardware design requirements and recommendations for IBM PC compatible personal computers, compiled by Microsoft and Intel Corporation d ...

PoweredUSB PoweredUSB, also known as Retail USB, USB PlusPower, USB +Power, and USB Power Plus, is an addition to the Universal Serial Bus standard that allows for higher-power devices to obtain power through their USB host instead of requi ...

ATX ATX (Advanced Technology eXtended) is a motherboard and power supply configuration specification developed by Intel in 1995 to improve on previous de facto standards like the AT design. It was the first major change in desktop computer enclo ...

, etc. A common convention for wiring systems in industrial buildings is: black jacket – AC less than , blue jacket – DC or communications, orange jacket – medium voltage or , red jacket or higher. Red-jacketed cable is also used for relatively low-voltage

fire alarm A fire alarm system warns people when smoke, fire, carbon monoxide or other fire-related or general notification emergency, emergencies are detected. These alarms may be activated automatically from smoke detectors and heat detectors or may also ...

wiring, but has a much different appearance. Local area network cables may also have non-standardised jacket colors identifying, for example, process control network vs. office automation networks, or to identify redundant network connections, but these codes vary by organization and facility.

Notes

References

{{reflist, refs= {{cite journal , title=Color coding , journal=

Service - A Monthly Digest of Radio and Allied Maintenance John Francis Rider (1900–1985) was an American radio engineer best known as publisher and author of over 125 books for radio and television servicing. He founded John F. Rider Publisher Inc. and was responsible for annual volumes of the ''Perp ...

, date=April 1932 , volume=1 , number=3 , editor-first1=John F. , editor-last1=Rider , editor-link1=John F. Rider , editor-first2=M. L. , editor-last2=Muhleman , publisher=

John F. Rider Publications, Inc. John Francis Rider (1900–1985) was an American radio engineer best known as publisher and author of over 125 books for radio and television servicing. He founded John F. Rider Publisher Inc. and was responsible for annual volumes of the ''Perp ...

, location=New York City, NY, USA , page=62 , url=https://www.americanradiohistory.com/Archive-Service-Magazine/30s/Service-1932-04.pdf , access-date=2019-11-15 , quote=Color coding of resistances used in receivers is not always according to the standard recommended by the RMA. Most of the manufacturers now are using this code. The following is a partial tabulation of receiver manufacturers and comments concerning their use of the body, tip and dot system. ��} (NB. Part 1/2 of a list of when each radio manufacturer first started using RMA color coded resistors.) {{cite journal , title=Color coding - Continued from April issue , journal=

, date=May 1932 , volume=1 , number=4 , editor-first1=John F. , editor-last1=Rider , editor-link1=John F. Rider , editor-first2=M. L. , editor-last2=Muhleman , publisher=

, location=New York City, NY, USA , page=89 , url=https://www.americanradiohistory.com/Archive-Service-Magazine/30s/Service-1932-05.pdf , access-date=2019-11-15 (NB. Part 2/2 of a list of when each radio manufacturer first started using RMA color coded resistors.) {{cite web , title=JEDEC History , publisher=

, url=http://www.jedec.com/join_jedec/history.cfm , access-date=2007-09-29 , url-status=dead , archive-url=https://web.archive.org/web/20070929155400/http://www.jedec.com/join_jedec/history.cfm , archive-date=2007-09-29 {{cite web , title=IEC 60062:2016-07 , date=July 2016 , edition=6 , url=https://www.sis.se/api/document/preview/8021442/ , access-date=2018-07-23 , url-status=live , archive-url=https://web.archive.org/web/20180723125246/https://www.sis.se/api/document/preview/8021442/ , archive-date=2018-07-23}

/ref> {{cite book , title=EIA RS-279: Color code for film resistors , publisher=

Electronic Industries Alliance The Electronic Industries Alliance (EIA; until 1997 Electronic Industries Association) was an American standards and trade organization composed as an alliance of trade associations for electronics manufacturers in the United States. They devel ...

, date=1963-08-01 {{cite web , title=MIL-HDBK-199C , url=https://tomwwolf.files.wordpress.com/2013/12/mil-hdbk-199c.pdf {{cite web , title=NZO series zero-ohm resistors , publisher=NIC Components Corp. , url=http://www.niccomp.com/products/series.asp?cate=Resistives&type=Leaded&series=NZO , archive-url=https://web.archive.org/web/20090104143106/http://www.niccomp.com/products/series.asp?cate=Resistives&type=Leaded&series=NZO , archive-date=2009-01-04 {{cite web , title=RF General , publisher=

, url=https://en.tdk.eu/download/531410/59a5850434250d35b39a06d5c80bf362/pdf-rfgeneral.pdf {{cite web , url=http://bradley.bradley.edu/~campbell/mnemonic.html , title=The Mnemonics Page , author-first=Dean , author-last=Campbell , publisher=

Bradley University Bradley University is a private university in Peoria, Illinois. Founded in 1897, Bradley University enrolls 5,400 students who are pursuing degrees in more than 100 undergraduate programs and more than 30 graduate programs in five colleges. Th ...

Chemistry Department {{cite book , title=Reference Data for Radio Engineers , chapter=Chapter 3: Audio and radio design , editor-first1=Harold H. , editor-last1=Buttner , editor-first2=H. T. , editor-last2=Kohlhaas , editor-first3=F. J. , editor-last3=Mann , publisher=

Federal Telephone and Radio Corporation The Federal Telegraph Company was a United States manufacturing and communications company that played a pivotal role in the 20th century in the development of radio communications. Founded in Palo Alto, California in 1909 by Cyril Frank Elwell, t ...

(FTR) , edition=2 , date=1946 , pages=52, 57 , url=http://www.tubebooks.org/Books/FTR_ref_data.pdf , access-date=2020-01-03 , url-status=live , archive-url=https://web.archive.org/web/20180516201551/http://www.tubebooks.org/Books/FTR_ref_data.pdf , archive-date=2018-05-16 {{cite book , title=Electrical Engineering Science , author-first1=Preston R. , author-last1=Clement , author-first2=Walter Curtis , author-last2=Johnson , publisher=

McGraw-Hill McGraw Hill is an American educational publishing company and one of the "big three" educational publishers that publishes educational content, software, and services for pre-K through postgraduate education. The company also publishes referenc ...

, date=1960 , pag
115
, url=https://archive.org/details/electricalengine0000clem , url-access=registration {{cite web , title=How To Read Old Style Resistors , date=2006-10-03 , url=http://www.philipstorr.id.au/radio/technical/BTS_Resistors.pdf , access-date=2016-12-19 , url-status=live , archive-url=https://web.archive.org/web/20161219160419/http://www.philipstorr.id.au/radio/technical/BTS_Resistors.pdf , archive-date=2016-12-19 {{cite web , title=RMA Resistor and Flexible Resistor Color Codes , url=http://www.radioremembered.org/rescode.htm , access-date=2016-12-19 , url-status=live , archive-url=https://web.archive.org/web/20161219160621/http://www.radioremembered.org/rescode.htm , archive-date=2016-12-19 {{cite web , title=The Antique Resistor Color Code , url=https://all-unique.com/PDF/Antique_Resistor_Color_Code.pdf , access-date=2016-12-19 , url-status=live , archive-url=https://web.archive.org/web/20161219160711/https://all-unique.com/PDF/Antique_Resistor_Color_Code.pdf , archive-date=2016-12-19 {{cite book , editor-first=Tony , editor-last=Dorbuck , title=The Radio Amateur's Handbook , edition=5 , date=1978 , publisher=

The American Radio Relay League The American Radio Relay League (ARRL) is the largest membership association of amateur radio enthusiasts in the United States. ARRL is a non-profit organization, and was co-founded on April 6, 1914, by Hiram Percy Maxim and Clarence D. Tuska of ...

, location=Connecticut, USA , orig-year=1977 , id=no ISBN , lccn=41-3345 , pages=553–554 {{cite book , editor-first=H. P. , editor-last=Westman , title=Reference Data for Radio Engineers , date=1968 , edition=5 , publisher= ITT / Howard W. Sams , lccn=43-14665 , pages=5-8–5-10

External links

; Online resistor calculators :
Multi-purpose resistor code converter
(4 and 5 band, mobile-friendly, shows nearest standard value) :
6 band resistor color code calculator
(easy lookup, 4 and 5 band calculators also available) ; Historical charts :

:

Color codes

color code A color code is a system for displaying information by using different colors. The earliest examples of color codes in use are for long-distance communication by use of flags, as in semaphore communication. The United Kingdom adopted a color c ...

Resistive components Mnemonics de:Widerstand (Bauelement)#Farbkodierung auf Widerst.C3.A4nden ja:受動素子#カラーコード pl:Opornik#Oznaczenia oporników