Electronic Color Code - Resistor, Capacitor and Inductor
An electronic color code is used to indicate the values or ratings of electronic components, usually for resistors, but also for capacitors, inductors, diodes and others. A separate code, the 25-pair color code, is used to identify wires in some telecommunications cables. Different codes are used for wire leads on devices such as transformers or in building wiring.
A useful mnemonic matches the first letter of the color code, in numeric order. Here are two that includes tolerance codes gold, silver, and none:
- Bad beer rots our young guts but vodka goes well – get some now.
- Black Brown ROY of Great Britain had a Very Good Wife who wore Gold and Silver Necklace.
The colors are sorted in the order of the visible light spectrum: 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.
The 25-pair color code, originally known as even-count color code, is a color code used to identify individual conductors in twisted-pair wiring for telecommunications.
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. Resistor values are always coded in ohms (symbol Ω), capacitors in
picofarads (pF),
and inductors
in microhenries
(µH).
Resistor Color Coding:
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 elements, and terminate transmission lines, among other uses.
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
- 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%, so the real resistance could lie anywhere
between 4,465 and 4,935 ohms.
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.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.
All coded components will have at
least two value bands and a multiplier; other bands are optional (italicised below).
The standard color code per EN 60062:2005
is as follows:
Color
|
Significant
figures |
Multiplier
|
Tolerance
|
Temp. Coefficient (ppm/KLetter
|
||||||||||
Black
|
0
|
×100
|
% Letter
|
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
|
–
|
|||||||||
A resistor which (read left to right)
displays the colors yellow, violet, yellow, brown. The first two bands represent
the digits 4, 7. The third band, another yellow, gives the
multiplier 104. The value is then 47 x 104 Ω,
or 470 kΩ. The brown band shows a tolerance of ±1%.
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 (PCB) by automatic component-insertion equipment. They are typically used on PCBs as insulating "bridges" where two traces would otherwise cross, or as soldered-in jumper wires for setting configurations.
| ||||||||||||||
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 value "steps" in each series.
Examples:
From top to bottom:
- Green-Blue-Black-Black-Brown
- 560 ohms ± 1%
- Red-Red-Orange-Gold
- 22,000 ohms ± 5%
- Yellow-Violet-Brown-Gold
- 470 ohms ± 5%
- Blue-Gray-Black-Gold
- 68 ohms ± 5%
The physical size of a resistor is
indicative of the power it can dissipate, not of its resistance.
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 = 220,00 (excluding default, silver, or gold tolerance)
- Red, red, black, red = 220 followed by 2 zeroes = 22,000 (excluding brown or other band for tolerance)
A 2260 Ω, 1% precision resistor with 5 color bands (E96 series), from top 2-2-6-1-1; the last two brown bands indicate the multiplier (×10), and the 1% tolerance. The larger gap before the tolerance band is somewhat difficult to distinguish.
Inductor Color Coding:
An
inductor establishes a magnetic field when current passes through it. Most of
the inductors are in the range of milli Henry (mH) or micro Henry (µH). These
are available with air, ferrite and iron cores. In today’s market there are
several inductors available from various manufacturers and their size varies
from larger to smaller units.
Inductor
values can be determined mainly by two ways, namely text coding and color
coding methods. Some inductors are larger in size, thus often their values are
printed on their body (name plate details).
However,
for smaller inductors, abbreviation or text is used because there may not be
enough room , for printing the actual value on it. Also, some inductor values
can be determined by reading color on the body of inductors by comparing them
with color coding chart. The
value of the inductor is printed on inductor body which consists of numerical
digits and alphabets. For this marking, micro Henry is the fundamental unit of
measurement (even if no units are given). The following are the steps of
identifying the value of inductor by using text marking method.
- It consists of three or four letters (including alphabets and numerical digits).
- First two digits indicate the value.
- Third digit is the power to be applied for the first two , this means it is the multiplier and power of 10. For example, 101 is expressed as 10*101 micro Henry (µH).
- Suffix or fourth letter or alphabet
represents the tolerance value of the inductor. Suppose if this letter is
K, then tolerance value is ± 10%, for J it is ± 5%, for M it is ± 20% and
so on. Follow the tolerance value table given below to know each letter
value.
The color coding system for inductors is very similar to that of resistors, especially in case of molded inductors. This color coding is in accordance with the color code table. Starting from the band closest to the one end, this color code sequence is identified. 4-band and 5-band color coding methods are described below with examples.
the 4-band inductor consisting four different color bands. Similar to the number coding, first and second color bands represents the first and second digits of the value, third color band is the multiplier and fourth band is the tolerance.Therefore the value of inductor can be determined by reading the colors of inductor body and comparing them with color code chart. It is to be noted that the result of this color coded value is in the unit of micro Henry (µH).
The table below shown gives the color corresponding to the numerical values for a four band inductor.First two digits, i.e., 2 and 2 represent the first two digits of the inductor value. Third digit, 3 is the multiplier and hence it is 10^3 = 1000. Now, multiplying with first two digits we get 22000.Now, it is to be noted that no units are given, hence this value is in micro Henry (µH). Thus the value becomes 22000 µH or 22mH.Last letter K represents the tolerance and is equal to ± 10%.
Therefore, this is a 22000 µH or 22mH inductor with ± 10% tolerance.
Example:
Initially, note down the tolerance percentage of the inductor which is mostly colored in gold, silver and black.Now note the colors from other end of an inductor. In the inductor the first band is red; according to the above table the number associated with this color is 2.
Now move to second band, observe the color and note the associated number according to the color given in the table. Here, the second band is violet and its number is 7. Then the value becomes ‘27’.
Coming to 3rd band i.e., multiplier is brown in color and its corresponding number is 10.
Thus the inductor value is 27 X 10 uH = 270 uH with a tolerance rating of ±5%.
In some cases we can have this multiplier band color as gold or silver. If the multiplier is gold divide the value by ‘10’ and if the multiplier band is silver, divide the value by ‘100’.
5-Band Inductor Color Code (Military Standard Inductor Color Code)
Usually cylindrical molded inductors are marked with 5 coloured bands. In this, one end of the coil consists of a wide silver band which identifies the military radio-frequency inductors. The next three bands indicate the value of inductance in micro Henries while 4th band indicates the tolerance.These inductors consist of tolerance values from 1% to 20%. For inductance values less than 10, the second or third band is gold which represents the decimal point. Then remaining bands indicates the two significant bits, and tolerance.
For inductance values equal or more than 10, first two bands represent the significant bits, third one is multiplier and fourth one is tolerance while considering MIL band.
In the above figure, inductor consists of following colors:
1st band – silver (military inductor indicator)
2nd band – red (2)
3rd band – violet (7)
4th band – brown (1 or × 10)
5th band – gold (±5% tolerance)
Thus the inductor value is 270 uH ±5%.
5-Band Inductor Color Code Example for the Values Less Than 10 H
A gold band is used in either 2-band or 3-band , which indicates the decimal point. Therefore, the 4th band acts as digit instead of a multiplier. If these two bands that is 2-band or 3-band does not contain gold coloured band then the 4-band acts as a multiplier.
Capacitor Color Coding:
The capacitors have specific values which are marked on to
the body of the capacitor, that helps to understand the capacitance and other properties of it. The important values for the
capacitor are the capacitance, tolerance, voltage rating, temperature
coefficient etc. These are usually marked on the body of the
capacitor in the alphanumeric form. There are many decimal values that are used
as capacitor values where the reading becomes difficult without the help of a capacitor value chart. To reduce the confusion involved with the letters,
numbers, and decimals used in representing capacitor values and also to prevent
misreading the values of the capacitor, an international color coding scheme
was introduced. The capacitor color code represents a simple and
efficient way of reading capacitor values and tolerances.
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.
Color
|
Significant digits
|
Multiplier
|
Tolerance
|
Characteristic
|
DC working voltage (V)
|
Operating temperature (°C)
|
EIA/vibration
|
|
Black
|
0
|
1
|
—
|
—
|
—
|
−55 to +70
|
10 to 55 Hz
|
|
Brown
|
1
|
10
|
±1%
|
B
|
100
|
—
|
—
|
|
Red
|
2
|
100
|
±2%
|
C
|
—
|
−55 to +85
|
—
|
|
Orange
|
3
|
1,000
|
—
|
D
|
300
|
—
|
—
|
|
Yellow
|
4
|
10,000
|
—
|
E
|
—
|
−55 to +125
|
10 to 2000 Hz
|
|
Green
|
5
|
100,000
|
±0.5%
|
F
|
500
|
—
|
—
|
|
Blue
|
6
|
1,000,000
|
—
|
—
|
—
|
−55 to +150
|
—
|
|
Violet
|
7
|
10,000,000
|
—
|
—
|
—
|
—
|
—
|
|
Grey
|
8
|
—
|
—
|
—
|
—
|
—
|
—
|
|
White
|
9
|
—
|
—
|
—
|
—
|
—
|
EIA
|
|
Gold
|
—
|
—
|
±5% [nb 3 Or
±0.5 pF, whichever is greater.]
|
—
|
1000
|
—
|
—
|
|
Silver
|
—
|
—
|
±10%
|
—
|
—
|
—
|
—
|
|
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
film
and "gum drop" tantalum electrolytic capacitors may also
be color-coded to give the value, working voltage and tolerance.
In small types of capacitors such as
film or disc form, instead of the color coding, the capacitance is given as a
letter or a number code. The code consists of 2 or 3 numbers and an optional
tolerance letter code to identify the tolerance.
When a 2
letter code is used, the value of the capacitor is denoted in picofarads such
as 10 = 10pf, 22 = 22 pf, and 100 = 100 pf etc. The 3 letter code is used to
denote the value of capacitor, the first two digits for the first and the
second value of the capacitor and the third one is multiplier in picofarads
which multiplies in multiples of 10. For example a capacitor with a value 251 =
25 * 10 = 250 pf and 102 = 10 * 100 = 1000 pF etc. There is an additional
letter included in a 3 digit code to include the tolerance measurement of the
capacitor. For example a capacitor with a value 103J printed on the body, which
denotes the 1st and 2nd digits as the 1st and 2nd value of the capacitor and
the 3rd one is denoted as the multiplier in picofarads and the letter J is the
tolerance.
10 * 1000
= 10,000 pf and the letter J denotes a tolerance of +/- 5%
The
capacitance is 10,000 pF which is equivalent to 10 nF or 0.010 mF with a
tolerance of +/- 5%
Printed Numbers: (SMT Coding)
Color bands were used because they were easily and cheaply printed on tiny components. However, there were drawbacks, especially for color blind 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.
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,
normally use alphanumeric codes, not colors.
0Ω and 27Ω (27×100)
surface-mount resistors
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, a capacitor marked 104 is
100 nF
(10x104 pF), and an inductor marked 475 is 4.7 H
(4,700,000 µH). This can be confusing; a resistor marked 270 might
seem to be a 270 Ω unit, when the value is actually 27 Ω (27×100).
A similar method is used to code precision surface mount resistors by using a
4-digit code which has 3 significant figures and a power of ten multiplier.
Using the same example as above, 4701 would represent a 470x101=4700 Ω,
1% resistor. Another way is to use the "kilo-" or "mega-" prefixes
in place of the decimal point:
1K2 = 1.2 kΩ = 1,200 Ω
M47 = 0.47 MΩ = 470,000 Ω
68R = 68 Ω
For some 1% resistors, a three-digit alphanumeric code is used, which is not obviously related to the value but can be derived from a table of 1% values. For instance, a resistor marked 68C is 499(68) × 100(C) = 49,900 Ω. In this case the value 499 is the 68th entry of the E96 series of preferred 1% values. The multiplier letters are as follows:
Z ×10-3 0.001
Y or R ×10-2 0.01
X or S ×10-1 0.1
A ×100 1
B or H ×101 10
C ×102 100
D ×103 1000
E ×104 10000
F ×105 100000
Some inductors consist of color dots on surface of the device instead of bands and these are very small in size. Generally these are coded according to the top colored dot on the surface. From this top dot we have to calculate the inductor value in clockwise direction. These dots will not indicate polarity. This type of inductors measured in nano-henries.
 |
| Dot SMD Inductor |
Green and red color indicates the value of inductor in nano Henries and the orange color indicates the multiplier.
Thus the value of this inductor is 52 103=52,000 nH
If only single dot is represented, the specifications of the inductor must be referred from data sheet of that particular series to that of corresponding manufacture.
 |
| Tantalum SMD Capacitor |
No comments:
Post a Comment