Understanding the Electronic Color Code for Resistors

the electronic color code was developed in the early 1920s by an organization called the radio Manufacturers

Association as a standard way of marking resistors and some other electronic components such as capacitors and

inductors in this program we will focus on resistors since that is its primary use today the advantages of color coding

over printed text on physically small components are the inherent increase in marking area which makes the values

easier to read without magnification and a 360 degree viewing angle which cannot be achieved with text color coded

markings are also more resistant to abrasion on the other hand color degradation due to it aging oxidation

and overheating can be a problem to read a color code is easy the colors represent numbers notice that the

numbers form a sequence starting with black for zero Brown for 1 red for 2 orange for 3 yellow for 4 green for 5

blue for 6 phylla for 7 gray for 8 and white for 9 notice that red orange yellow green blue and violet are the

colors of the color spectrum in order these are the colors of a rainbow if you can remember the colors of the rainbow

red orange yellow green blue and violet all you need to remember is that the numbers start with black the absence of

all color then brown go through the five colors of the rainbow and end with gray and then white the mixture of all colors

another way to remember is to employ a memory aid called a mnemonic such as big boys race our young girls but violet

generally wins it is well known that some mnemonics are more memorable than others but most of these variations like

the infamous bad boys version are often considered inappropriate for classrooms other languages have other mnemonics for

this color code a rough translation of the French version is don't eat anything or I'll beat you violently big animal

most resistors have four color stripes although some called precision resistors have five bands

reading a color code is simple with four band resistors the first and second colors represent the first two digits of

the resistance value in ohms the third band represents the multiplier or number of zeros after the first two digits an

exception to this is when the third band is silver or gold if it is gold the first two digits are multiplied by 0.1

if it is silver the first digits are multiplied by point zero one resistor color codes are like scientific numbers

with a mantissa and an exponent or power of 10 the fourth band on a four band resistor is called the tolerance band

and is either gold 5% or silver 10% today 5% is a standard grade resistor let's try some examples here is a

resistor with a color code Brown black red gold the first band is brown which is one the

second ban is black which is zero and the third band is red so the code is 1 0 2 the third color or red represents tan

raised to the 2 power or 100 this is the same as 2 more zeros so we have 1 0 0 0 or 1000 the fourth band is 5% tolerance

so a brown black red gold resistor is 1000 ohms plus or minus 5% now five percent of a thousand is 50 so this

resistor can have a value from 950 to 1050 ohms here is another resistor yellow violet red silver yellow is for

violet is 7 red is 2 so this is a four seven and two more zeros the first three colors represent four seven and then two

zeros so this is a nominal 4700 ohm resistor the fourth band is silver so this resistor has a tolerance of plus or

minus 10% so we have a 4700 ohm resistor with a 10% tolerance now 10% of 4700 is 470 so this resistor is guaranteed to be

within the range of 4700 ohms plus or minus 470 ohms or 42:32 51 70 ohms here is another resistor white violent black

goal white is nine violet is seven and black is zero so the color code reads nine

seven zero it is a common mistake to interpret this as 970 but remember the third digit is the number of zeros so 10

raised to the zero power is one the multiplier is one there are no zeros appended to the digits nine and seven so

it is just ninety seven owns the fourth man is gold or five percent so this is a ninety seven ohm resistor with a

tolerance of plus or minus five percent five percent of 97 is four point eight five if we add and subtract that from

ninety seven that means this resistor value has to fall within the range of ninety two point one five to 100 and one

point eight five ohms another example yellow violet orange gold that is four seven three or forty seven with three

zeros after it that is forty seven thousand ohms or what we would call 47 kilo ohms or 47k

ohms for short this resistor has a tolerance range of 47 K plus or minus five percent which equals 44 six 52 49

350 ohms another example violet green blue gold this is the code seven five six or

seventy five with six zeros after it that is seventy five million ohms or we can call it 75 mega ohms or 75 M ohms

for short notice the capital letter M here is another four band resistor with low valued resistance its colors are

green red gold silver green is five red is to Gold and a third band is a multiplier of 0.1 so the code reads five

to zero point one and so we multiply 52 by point zero by point one giving a nominal value of five point two ohms the

fourth band is silver so this is 10% five point two plus or minus 10% gives us a range of four point six eight to

five point seven two ohms therefore to be called at 5.20 Murs with a tolerance of 10% the actual value

must fall between four point six eight and five point seven two ohms to review for banned resistors consists of two

color codes representing the first two digits of the number followed by a multiplier and then the tolerance band

not all resistance have a 10 or 5% tolerance bands many years ago some resistors had a 20% tolerance which was

indicated by not having a fourth color band you might find a three band resistor in an antique radio or

television for most applications 5% resistors or 10% is more than adequate but some requirements a more precise

resistor must be used precision resistors commonly use a five band color code for precision resistors the first

second and third bands give the first three digits of the resistance value the fourth band is the multiplier banned v

ban is a tolerance band a brown band represents a 1% tolerance a red band 2% a green band point five blue 0.25 violet

point one and a gray band represents point zero five percent tolerance for example the first three bands of this

resistor indicate the first three digits two zero zero the fourth band the multiplier band is brown for one or ten

raised to the 1 power in other words just ten so we get to zero zero with another zero after it or 2000 ohms as

the nominal value the fifth band is violet indicating a tolerance of 0.1% so this resistor has a value of two

thousand ohms plus or minus 0.1 percent this resistor is guaranteed to be within point 1% of 2000 ohms to calculate this

we convert 0.1 percent to a decimal number by dividing by 100 which gives point zero zero one and multiply by two

thousand to get two so this resistor is guaranteed to be two thousand plus or minus two ohms it can be no less than

1998 and no greater than two thousand and two ohms what has been described in this presentation is the most common

ways that color codes are used on resistors there are other uncommon variations such as precision resistors

with six bands including a band after the tolerance band that into indicates temperature compensation or quality

codes that are not standardized also some resistors do not use color codes but have a number printed on

this tiny surface-mount resistor has 1 0-0 printed on it it uses the same coding system as color codes this one is

1 0 with zero zeros after it or just 10 ohms this surface-mount resistor has 1/5 1 printed on it that would be 15

multiplied by 10 raised to the 1 power or 15 times 10 in other words 1 5 with 1 0 after it 150 ohms surface mount

resistors are sometimes called SMT surface mount technology our SMD surface mount device resistors surface

mount technology is used in all sorts of devices which must be small in size large power resistors also have the

resistance values printed on them since there is plenty of space they are often printed without using any

scientific number code having learned the common color codes you will be well prepared for selecting the most common

electronic component the resistor [Music]