EIA Standard Color-Code

Can you determine a resistor’s ohmic value from the color bands painted on its body? The EIA (Electronic Industries Alliance) standard color-code is used to identify the values of many electronic components that you will come into contact with as an electronic engineer or technician. This is an industry standard universal color-code and is used world-wide. Many electronic component shapes or physical sizes do not facilitate the use of printed numbers or letters on their bodies to specify their value or identification number, they require the use of color paint applied in a distinct pattern on their bodies for these identifiers. The use of color positional placements to identify component values is widely used by electronics component manufactures and the industry in general. The colors are easily seen and their patterns allow for a quick interpretation of the components value or part number.

Ten colors are used to identify the digits from 0 through 9. Two additional colors, gold and silver, are used to represent negative power-of-ten notation exponent numbers as well as representing a resistor’s standard tolerance variation values; in other words these colors have special meanings.

EIA Color-Code

Digit	Color	Color

0		Black

1		Brown

2		Red

3		Orange

4		Yellow

5		Green

6		Blue

7		Violet

8		Gray

9		White

10^-1 / 5%		Gold

10^-2 / 10%		Silver

To help in the memorization of the digit to color relationships we will again use a mnemonic memory aid. It still has to be somewhat stupid in order to remember. The most commonly used mnemonic for the EIA color-code today is:

Black Birds Ruin Our Yellow Grain Butchering Very Good Wheat – God Said.

Participation Exercise: Write the above memory aid four or five time on scratch paper to help you visualize the saying in your mind.

To apply this mnemonic for the recreation of the color-code chart follow these basic steps to determine each digits color assignment:

2. Next to each number, in succession, record the first letter of each word of the mnemonic.

3. Use the recorded letter to determine the name of the color for each numeric digit.

With the letters now by a corresponding number you will need to determine what color each letter represents. Notice that there are three Bs and two Gs, so let’s wait for those. Look at the digit 2, which has an R by it. The R must represent Red, next look at the O, your right that's for orange. V is for violet and W for white; that was pretty easy. Now focus of the digits 5 and 8. We know that the G's must be for green and gray. Here is another outrageous learning aid - if you are a good gardener people say you have a green thumb, which is the fifth finger on your hand so the digit 5 must be green, so the digit 8 is therefore gray. Now we have the Gs licked. For the Bs, I use an analogy of dark to light. At midnight or zero o'clock, the sky is black, at 1a.m. the sky is not as dark so call it brown and at 6a.m. the sky is blue; I know it’s stupid but it works.

That’s it; you now have a way of generating the SI (International Standard) standard color-code whenever it is needed. We will use the color-code for every lab session; after a few weeks you will start to remember the color and digit assignments and you will not have to create the color-code chart as often.

Check for Understanding

On a separate sheet of paper generate a color-code chart using the steps listed above.

1. A diode has the colors White, Brown, Yellow painted on its surface. Write the diodes part number if each color represents discrete numeric digits.

2. A transistor has the colors Orange, White, Black, Yellow painted on its surface. Write the transistors part number if each color represents discrete numeric digits.