# Inductor Colour Codes

What you´ll learn in Module 3.4
• After studying this section, you should:
•   • Know the EIA and military standard colour codes for inductors.
•   • Be able to calculate the value of colour coded inductors.

## Fig 3.4.1 Four Band Standard EIA Colour Code For Inductors.

Therefore value = 27 x10 = 270µH +/-20%

Band 1 2 3 4
Meaning 1st Digit 2nd Digit Multiplier (No. of zeros) Tolerance %
Gold     x 0.1 (divide by 10) +/-5%
Silver     x 0.01 (divide by 100) +/-10%
Black 0 0 x1 (No Zeros) +/-20%
Brown 1 1 x10 (0)
Red 2 2 x100 (00)
Orange 3 3 x1000 (000)
Yellow 4 4 x10000 (0,000)
Green 5 5
Blue 6 6
Violet 7 7
Grey 8 8
White 9 9

Note: If no Band 4 is used, tolerance is also +/-20%

## Fig 3.4.2 Five Band Military Standard Inductor Colour Code

Band 1 2 3 4 5
Meaning
(See Notes)
Mil. Spec. Digit or
Dec. point
Digit or
Dec. point
Digit
(or Multiplier)
Tolerance %
Gold   Decimal
point
Decimal
point
+/-5%
Silver Always Silver
double width
+/-10%
Black   0 0 0
(or x 1)
+/-20%
Brown   1 1 1
(or x 10)
+/-1%
Red   2 2 2
(or x 100)
+/-2%
Orange   3 3 3
(or x 1,000)
+/-3%
Yellow   4 4 4
(or x 10,000)
+/-4%
Green   5 5 5
Blue   6 6 6
Violet   7 7 7
Grey   8 8 8
White   9 9 9

### Notes:

The military standard for cylindrical inductors specifies 5 coloured bands The same colours are used as in the EIA 4 band code, but:

For band 1, a double width sliver band is used to signify Military Standard.

### For values less than 10µH:

Bands 2, 3 and 4 indicate the value of inductance in µH

A gold band might be used in either band 2 or band 3. In either of these two bands, gold indicates a decimal point and band 4 is used as a digit instead of a multiplier band.

When no gold band is present in bands 2 or 3, band 4 is a multipier band.

For example:

• If bands 2,3 and 4 are red, gold, red the value would be 2.2 µH
• If bands 2,3 and 4 are gold, yellow, violet the value would be 0.47 µH (470nH)

Band 5 indicates the tolerance between 1% and 20%

### For values of 10µH or more:

Bands 2 and 3 represent basic value, and band 4 gives the number of zeros.

For example:

If bands 2, 3 and 4 are red, violet, orange the value would be 27000 µH

### Surface Mount Device(SMD) or Chip Inductor Codes.

For inductors of a very small physical size, coloured dots may be used instead of bands. In such cases, The silver dot indicating a Military (Mil) specification will be larger than the other dots and will be placed a the beginning of the dot sequence.

In some cases only a single coloured dot is used,and for their meaning it is neccesary to refer to individual manufacturers data for accurate interpretation.

Dot code examples from Coilcraft Inc. http://www.coilcraft.com/colrcode.cfm

Dot code examples from Viking Tech Corporation. http://www.vikingamerica.com/ftp/NL.pdf