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I have been reverse engineering since before the advent of solid state circuits. When I looked up color codes here at Instructables, I was surprised to find just a few one page Instructables on component color codes.

The color codes we all know and love come from EIA standards, (Electronics Industries Association) and they were used on almost every device at one time or another, even vacuum tubes. They are still in use on many devices used in electronics today.

I work on many older electronic devices; capacitors and resistors can go out of tolerance with time. Older devices often have color coded components not seen in newer electronics today, and the exact component quite often is no longer available. I can reverse engineer the circuit and guess at what the appropriate replacement component is and its value or I can look up the color code and select a modern replacement that will work. Looking up the components values and properties from its color code is easier than reverse engineering from scratch.

These are some of the color codes I use when working on electronics.

Step 1: EIA Standard Color Code

The EIA standard color code used in electronics is simple; although through the year’s colors and the color bars have remained basically the same, some of their values have changed with technology. Most color codes read from left to right with a gap on the right side and round components may have the gap on the bottom.

The EIA standard color code for significant numbers; start at two significant digits and go up to four significant digits in some components and semiconductors. Starting at black for zero, brown for one, red for two, orange for three, yellow for four, green for five, blue for six, violet for seven, gray for eight, and white for nine.

The multiplier is the same colors as the significant digits only you multiply in the tens depending on the color, I move the decimal place over the number of zeros indicated by the color’s number, nothing for black, one zero for brown, two zeros for red, and so on just like the significant digits. Also depending on the component’s color code adding Gold and Silver to the multiplier, divide by 10 for gold or divide by 100 for silver.

Gold 0.1

Silver 0.01

So a resistor with a brown black and red color band followed by a silver band to the far right is a 1,000 Ω resistor with a 10% tolerance, or a 1 KΩ resistor with a 10% tolerance.

Tolerance is the accuracy of the component to the color code. So if a resistors color code indicates it is a 1,000 Ω resistor with a 10% tolerance, the resistors true resistance is somewhere between 1,100 Ω and 900 Ω. Tolerance has changed with technology and growing precision many older components have tolerances up to twenty percent. These components will have a black or no color band where the tolerance band should be.

The voltage color band is on capacitors, but not all capacitors have a marked voltage rating and not all capacitor types have the same voltage ratings. So the voltage color code of one group of capacitors will have different values from the voltage color code of another group of capacitors. The voltage rating is the maximum voltage you can apply to a capacitor before it starts to break down.

Temperature coefficient, “alpha” (α), is not shown on the basic color code. On some resistors and capacitors you will find a color band for temperature coefficient. The temperature coefficient on capacitors and resistors indicates the rate of value change of the component with changes in temperature of the component. Resistor and capacitor values change for any temperature other than the standard temperature usually specified at 20 degrees Celsius.

For pure metals, this coefficient is a positive number, meaning that resistance increases with increasing temperature. For the elements like carbon, silicon, and germanium, this coefficient is a negative number, meaning that resistance decreases with increasing temperature. This change in resistance and capacitance can affect the performance of some electronics devices.

The amount of change is determined with these formulas:

R = Rref [1+α(T – Tref)]

C = Cref [1 + α(T – Tref)]

Where

R = Resistance of resistor at temperature “T”

Rref = resistance of resistor at Tref usually 20⁰ C (Celsius)

α = Temperature coefficient of the component

T = Temperature of component in degrees Celsius

Tref = Temperature reference of the component usually 20⁰ C (Celsius)

And

C = Capacitance of capacitor at temperature “T”

Cref = Capacitance of capacitor at Tref usually 20⁰ C (Celsius)

α = Temperature coefficient of the component

T = Temperature of component in degrees Celsius

Tref = Temperature reference of the component usually 20⁰ C (Celsius)

Step 2: Resistor Color Codes

All resistance is measured in ohms (Ω), resistors under 1 ohm are called milliohms (mΩ). Resistors 1 ohm and over but under 1,000 ohms are usually called ohm (Ω). Resistors from 1,000 ohm but under 1,000,000 ohm are usually called kilo ohm (KΩ). And resistors from 1,000,000 up are called mega ohm (MΩ).

Most color coded resistors read from left to right with a gap and the tolerance to the far right. The first color band on the left is the first significant digit. The second significant digit is the second color band from the left. The multiplier is the third color band from the left, and the tolerance is the fourth color band on the far right. However not all resistors read that way.

Older resistors may only have three bands to the left with no color band on the right, making its tolerance 20%.

With five band resistors the third color band is the third significant digit, the fourth color band is the multiplier and the fifth color band to the far right is the tolerance.

Six band resistors have the sixth band next to the tolerance or where the tolerance should be with the tolerance beside the multiplier and the sixth band is the temperature coefficient.

Step 3: Ceramic Capacitor Color Code

All capacitance is measured in farads; picofarads (pF) 0.000,000,000,001 farad, nanofarads (nF) 0.000,000,001 farad and microfarads (uF) 0.000,001 farad. Ceramic capacitors are marked in picofarads (pF).

Three band ceramic capacitors and there color codes read much like color coded resistors, starting from left to right with a gap on the far right or the bottom of disk shaped capacitors. The first color band sometimes larger and more pronounced on the left side of the capacitor is the first significant digit. The second significant digit is the second color band from the left. The multiplier is the third color band from the left. These capacitors may have a tolerance of 20%.

Four band ceramic capacitors read much the same the fourth band is the tolerance on the far right.

Five band ceramic capacitors reading from the left to the right, the first color band on the left often larger and more pronounced is the temperature coefficient, and then comes the first significant digit, the second significant digit, the multiplier, and the far right is the tolerance.

Step 4: Mica and Molded Paper Capacitor Color Codes

Capacitance on mica and molded paper capacitors are marked in picofarads (pF). Mica and molded paper capacitor color codes have from three to six colored dots and are marked by an arrow of some kind for reading. Although you read the colors much like color coded resistors, they don’t always read in the same order. In addition they have Type, Voltage, and Class in their color codes. So pay attention to the posted color code chart when reading them.

Step 5: Capacitors With Voltage in the Color Code

Ceramic capacitors with voltage ratings are marked in picofarads (pF) and read much like other ceramic color coded capacitors, starting from left to right with a gap on the far right of the capacitor. The first color band may be larger and on the left of the capacitor is the first significant digit. The second color band from the left is the same size as the first is the second significant digit. Slightly smaller the third color band from the left is the multiplier, and the tolerance is the fourth color band with voltage on the far right.

Ceramic disk capacitor color codes with voltage, read much the same, but you start reading the color bands from the top and read to the bottom of the capacitor. The first color band on the top is the voltage, the second band from the top is the first significant digit. The second significant digit is the third color band from the top. The multiplier is the fourth color band from the top, and the tolerance is the fifth color band on the bottom.

Metalized Polyester and Pin capacitors come with and without voltage ratings. Starting from the top and reading the color bands to the bottom of the capacitor. The first color band on the top is the first significant digit. The second significant digit is the second color band from the top. The multiplier is the third color band from the top, and the tolerance is the fourth color band, when they have a voltage rating it is the fifth color band on the bottom of the capacitor.

Step 6: Tantalum Capacitor Color Codes

Tantalum capacitors are electrolytic capacitors and their capacitance is marked in microfarads (uF). Tantalum capacitor color codes with voltage, read much like color coded resistors, starting from the top to the bottom of the capacitor.

The first color band on the top is the first significant digit. The second color band from the top is the second significant digit. The multiplier is the dot in the middle of the first and second color bands. The voltage is the bottom color band with the positive lead to the right when you are looking at the multiplier dot. Usually without a tolerance they have an added color pink, for 35 volts to the color code.

Step 7: Inductor Color Codes

Inductance is measured in Henries, there are nanohenries (nH) 0.000,000,001 henries, microhenries (uH) 0.000,001 henries, millihenries (mH) 0.001 henries. Other than SMD (Surface Mounted Device) inductors being read in nanohenries (nH), color coded inductors are read in microhenries (uH).

Like resistors, inductors are read from left to right with a gap and the tolerance to the far right. The first color band on the left is the first significant digit. The second significant digit is the second color band from the left. The multiplier is the third color band from the left, and the tolerance is the fourth color band on the far right. However not all of them are read that way.

Dipped inductors the first color dot on the left is the multiplier, the second dot from the left is the second significant digit and the third dot is the first significant digit with no tolerance.

Some three color band inductors have no multiplier.

And five color band inductors with a silver band as the first color band on the left are military solderable leads.

Step 8: Diode Color Codes

Semiconductor color codes are less reliable than resistor, capacitor, or inductor color codes. Some color codes are maker specific as in this Philips SMD code book. Single color band diodes may tell you the type of diode and the cathode end of the diode, but without alphanumerical markings like (2.4). You would never know it is a 2.4 volt Zener diode.

Some manufactures that make two color band diodes use the same color bands for different series of diodes.

Most germanium diode color bands just tell you the cathode end of the diode.

And some manufactures that make three color band diodes use the same color bands for different series of diodes.

Step 9: Four Color Band Diodes

Four band diode color codes are much more reliable using color bands for alphanumerical representations for the part numbers you can look up on websites and data books. The first two color bands are prefixes the last two are numerals like the significant digits in a standard EIA color code.

These sites are good for looking up the datasheets once you have the part numbers.

http://www.maxim4u.com/

http://www.alldatasheet.com/

Step 10: JEDEC Series Diode Color Code

The JEDEC series diode color code assumes the first two digits are 1N, the next two to four digits in the part numbers are the color bands. Each color band represents numbers like the standard significant digits in the EIA color code. The last color band in four and five color band diodes is the suffix letter if the diode has a suffix.

This can make the diodes part number hard to read if you are not familiar with the diode are you looking at. Is it a 1N400G or a 1N4007?

In short diode color codes work best if you already know what diode you are working with.

Step 11: Transistor Color Codes

Unless you repair or reverse engineer older electronics like I do, you won’t have much use for transistor color codes. They were common at one time but they are not of much use today. The color code assumes standard transistor prefixes like 2N for JEDEC transistors. The significant digits are standard EIA color codes from two to four significant digits read from top to bottom. When the color bars are on the top of the transistor they are read from left to right.

So if the transistors color bands are red, red, red, red, meaning 2222. A quick look at the datasheet will tell you if it is a 600 mW NPN general purpose transistor like MPS2222 or 2N2222 or if it is a 2SD2222 power transistor.

Common Transistor Prefixes

MJ: Motorolla power, metal case

MJE: Motorolla power, plastic case

MPS: Motorolla low power, plastic case

MRF: Motorolla HF, VHF transistor

RCA: RCA

RCS: RCS

TIP: TI power transistor (platic case)

TIPL: TI planar power transistor

TIS: TI small transistor (plastic case)

ZT: Ferranti

ZTX: Ferranti

Pro-Electron prefixes.

BC

BD

BF

BL

BS

BU

And the last group of prefixes.

2SA

2SB

2SC

2SD

2SJ

2SK

Step 12: Integrated Circuit Color Codes

Like transistors integrated circuits used color codes for a short time the prefix was the first color bar the first set of significant numbers were the second color bar and the last two color bars are the last two significant numbers.

This is a list of company letter prefixes for Integrated Circuits manufacturers, normally these prefixes are used as the first part of the part number for a device. For example, a RCA logic device may have a part number CD4049, CD indicates it is a RCA device the remainder is the part number.

If the part number is MC14049 the device is made by Motorola, denoted by the MC.

CA; RCA (analog)

CD; RCA (digital)

DM; National Semiconductor (digital)

GD Goldstar (digital)

HA; Hitachi (analog)

HD; Hitachi (digital)

MC; Motorola

TA; Toshiba

TC; Toshiba

<p>Perhaps you can help with an identification. I have some board-pulled small (about 2.5mm long) glass bodied, leaded diodes which came from Sony or Panasonic audio gear, possibly dating from the late '90's. Some have a single green cathode band, some have a single white cathode band, also some shorter ones with a blue band (which came from something else though I think they might be zeners). I can't imagine they'd be anything other than general purpose diodes. The white band ones have a near identical Vf to a random 1N4148 I sampled.</p><p>You seem like you might be able suggest what type they might be!</p>
<p>Chances are the diodes are the same as the Mini MELF In step 8.</p><p>You and download the Philips datasheet in step 8, it has the single band color codes but it won't give you the exact diode just the group it belongs to.</p>
<p>Back in 1978 in tech school we learned the military resistor color code.</p><p>bad-boys-rape-our-young-girls-but-violet-gives-willing for -gold or-silver</p><p>Instructor was retired from Army.</p>
<p>I still remember the one we were made to say over and over if we called our weapon a gun.</p>
<p>Was that &quot;This is my rifle, this is my gun. This one's for killing this one's for fun.&quot;? :) </p>
<p>Yep</p>
<p>I learned the same thing in Vo-Tech in the '80s as well. Along with a lot of other stuff along the way.</p>
<p>That's how I learned it, too, but with the alternate ending &quot;. . . But Veto Getting Wed.&quot; I wonder what the politically correct mnemonic is these days. Anyone? Or are EEs still politically incorrect? LOL</p><p>Great 'ible, though. Always nice to have all the codes in one place.</p>
<p>In my Jr. College class Electronic Engineering Technology in 1970 my instructor was a retired Navy Chief Petty Officer. The class was in an uproar all the time. This was the story the Chief used to explain the significance of the color &quot;black value&quot; of the resistor color code in the third band. Quote, &quot;Black in the third band has no value, it means nothing, none.&quot; Then the Chief asked me and I immediately picked up on his actions this was going to be one of those uproarious moments, &quot;Do you know what a nun is?&quot; I replied, &quot;No Sir.&quot; He continued, &quot;A nun is a gal that ain't got none, don't want none, and doesn't want anybody else to get nun.&quot; It took five minutes for the class to settle down. Today because of all the PC baloney if the Chief said that he would be hauled into HR for sexual harassment sensitivity training or fired. </p>
<p>I learned the color code Bad Boys ect. in 78 when I started my electronic assembly job at Sperry Univac... I have never forgot it and you tell kids today how to remember the color code like that, they give you a blank or disgusting stare...no sense of haha in todays world... Thanks</p>
<p>I also learned that code but here is one for those that what you described BAD BOYS RUN ON YOUNG GRASS BUT VIOLETS GROW WILD</p>
very informative. ......for new electronic learner...
<p>Thank you</p>
<p>or download the program <a href="https://play.google.com/store/apps/details?id=it.android.demi.elettronica&hl=en" rel="nofollow">https://play.google.com/store/apps/details?id=it.a...</a></p><p>:)</p>
<p>Ok I didn't down load the app, did you?</p><p>The reason I ask is when I looked through its apps I could not find color codes for capacitors of any kind. And the same for semiconductors.</p>
<p>Thanks for all of this information. I got my certificate in Digital Electronics and Basic Lasers in the late '80s. I worked in electronics manufacturing transformers at first and then as Senior Bench Tech for nearly 17 yrs before the last &quot;non-driver&quot; took me out of work for good. Much of this information I have never heard of....whether it be too old or too new. Though I did notice you used the moniker &quot;milla&quot; a number of times. I was taught this was &quot;milli&quot;. Was I taught wrong or are these interchangeable?</p><p>Again, thank you so much for all of this USEFUL information! I still dabble a bit at home since nothing is made the way it used to be. Nothing like crap solder joints on so many products today that cause parts to go bad or just stop working because they need to be touched up. I now have information to look back on if I don't understand something I see. That and the use of my trusty Huntron Tracker.....LOVE IT!</p>
I have noticed that some people spell words as they say them, not that this is the case with this author. I have to agree with you that milli is the correct spelling. This tiny error doesn't detract in any way from the excellent work he has done producing this instructable, well done Sir, I'm sure this will help loads of newbies and some of the longer standing hobbiest in the electronic field.
<p>spelling is really (or is it realy) relevant. Not!</p>
<p>If you want a laugh copy what I wrote in the inductors step and the spell check just said I spelled inductors wrong. Paste in the Instructables editor and watch how many words it says is spelled wrong. Then Google them and find out I not only spelled them right I used them right also.</p><p>Just like semiconductor color codes spellcheck is very unreliable so If I miss something please point it out, it makes my writing better. </p>
<p>The truth is dialect in Great Britain color is colour in the US color is color and in Canada both color and colour is correct.</p><p>Most of the time I try to write in US dialect but it can be challenging when both spellings are correct to you. </p>
<p>Ethnic spelling Milla and Milli.</p><p>and Thank you</p>
thank you. There is just so much information here that I have never seen before. Therefor, I wasn't sure if that was something new as well. I am sorry if this has caused anyone any difficulties.<br>Thank you again for so much information!
<p>I do appreciate this info as some are difficult to get if not impossible! Made me think of the white red etc. dot transistors 2n2646 and so on I could not get a supply or gen of them here later to discover the old slave BC 108 was a good replacement</p>
<p>You gave me an idea.</p><p>I have a substitution hand book for vacuum tubs.</p><p>And I have an RCA transistor book with a substitution reference section.</p><p>I should check and see what substitution guides are out there.</p><p>Thank you </p>
<p>An absolutely <strong>brilliant </strong>'ible - this is the first time I have ever seen all of this information in one place.</p><p>Only one thing is missing for our less enlightened readers - colour coded potentiometers. (I can never remember which war round to read the markings ;) so I use a meter.)</p>
<p>You know I never came across color coded<br>pots and potentiometers or a chart. But If I were to guess<br>like all other round components in the EIA standards,<br>like ceramic capacitors, gap in the color code on bottom and left to right or<br>top to bottom.</p><p>Most of the pots and potentiometers I come across ether just say their value or<br>use an alphanumerical code much like SMD resistors. For example103 or 10K for a<br>10 kΩ pot, and 1M5 or 155 for a 1.5 MΩ potentiometers.</p>
I've had skeleton pots colour coded but not the normal ones those for me have always had the value stamped into the metal. Excellent job Jo, as I said in another post, this will certainly help a lot of newbies. Well done sir ?
<p>Thank you</p>
The few I have come across are presets, marked on the polythene thumbwheel as a series of radial lines - 3 or 4 bands and no obvious indication of Lin or Log law.<br><br>The older colour coded front-panel pots (1950's vintage) are marked by three bands and a Ig or In - and are pretty obvious by the orientation of the lettering.
<p>SImply outstanding !!!</p>
<p>Hi Josehf</p><p>Thanx for post the best information about this subject.</p><p>It'll be a huge help for those starting out in the field of electronics and for those who are a bit rusty.</p><p>Do you mind if I could use some of your material in my training manual at work?</p><p>To Laparsons</p><p>I was taught the exact same thing and I've never forgotten it.</p>
<p>Thanks a bunch for this GREAT instructable. Please send the original pics to xyz@robwilson.net. I'll delete the email address from my server after receiving them. Thanks again.</p>
<p>Add my &quot;Thank you!&quot; to the list. It is nice having all of this in one place. People who are looking for nice charts can do an internet search for images. I have a very nice resistor chart that I found this way.</p>
<p>Thank you</p>
<p>Great info! I search through several library books for similar info to print out for my students.</p>
<p>Some detail can be lost with picks on this sight.</p><p>If you wan't sharp picks PM me your Email and I will send them to you.</p>
hello, I just want to say that you've made a mistake with counting the zeros you need for nanofarad. It should be 0.000,000,001 <br><br>greetings<br>Jason
<p>Darn I did pico twice didn't I.</p><p>You know I waited two weeks before posting it, reading it over and over looking for mistakes and I missed that one.</p><p>Thanks </p>
<p>Thank you sooooo much. I will be printing this out. Awesome Instructable!!!</p>
<p>If the details do not come out well PM me with your Email and I will send the original jpeg.</p>
<p>Awesome. Thanks Josehf!</p>
<p>Amazing. I wish you lived mext door to me! I am always out of my depth with electronics but as I rebuild electric bass guitars (hobby) some of them 50 years old I am always at a loss to find the right capacitors to work with a new old stock Potentiometer. As in today a bass is usually fitted with 250k Pots (for example),and 473 200v Cap for tone. But 50 years ago a 1 meg Pot was not unusuale but finding visual comparisons for the 1962 tone caps, and resisters for Treble bleed is such a struggle. there are no charts to refer to! The examples are hidden away inside collectors guitars! google is not much help. What a wonderful friend you would be! I just wish I understood what you were talking about. How about a class 'A Dummys Guide' for those of us that don't have your natural gift?</p>
<p>It&rsquo;s not that natural a talent, I had to<br>work at it in the beginning.</p><p>Classical Axe and amps and of course the<br>pots and potentiometers wear out, the capacitors and resistors go out of<br>tolerance with age, and the inductors burn from repeated heating. God forbid<br>you need a triode tube.</p><p>The higher voltages used in the older<br>instruments doesn&rsquo;t make it any easier. </p><p>A good electronics supply should be<br>helpful, but to get to one for me I have to travel 250 k so I had no choice but<br>to figure it out for myself. </p>
<p>Ohh man, you are so OP! ;)</p>
<p>Thank you</p>
<p>Anytime! ;)</p>
Thank youw best article I have ever read on Colour Codes
<p>Thank you</p>
Dude! Now that is an informative post! I was looking for this info the summer before last. I was put in charge of documenting inventory. most of the old drawers didn't have their labels on them anymore. I was like &quot;I know that's a resistor. but what is that square thing with 6 colored dots on it?&quot; It tool a lot of Internet searching to find the info. Anyway thanks for putting all of this into one place.
<p>Thank you</p>

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