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Resistor Color Codes Cheat Sheet (DRAFT) by [deleted]

How to read the color bands on a resistor

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Introd­uction - Resistor Color Codes

Resistors are devices that limit current flow and provide a voltage drop in electrical circuits. Because carbon resistors are physically small, they are color-­coded to identify their resistance value in Ohms. The use of color bands on the body of a resistor is the most common system for indicating the value of a resistor. Color-­coding is standa­rdized by the Electronic Industries Associ­ation (EIA).

Use the Resistor Color Code Chart to understand how to use the color code system. When looking at the chart, note the illust­ration of three round resistors with numerous color code bands. The first resistor in the chart (with 4 bands) tells you the minimum inform­ation you can learn from a resistor. The next (a 5-band code) provides a little more inform­ation about the resistor. The third resistor (a 6-band) provides even more inform­ation. Each color band is associated with a numerical value.

Typical 4-band, 5-band and 6-band resistors

4-Band: Reading the resistor from left to right, the first two color bands represent signif­icant digits , the third band represents the decimal multip­lier, and the fourth band represents the tolerance.
5-Band: The first three color bands represent signif­icant digits, the fourth band represents the decimal multip­lier, and the fifth band represents the tolerance.
6-Band: The first three color bands represent signif­icant digits, the fourth band represents the decimal multip­lier, the fifth band represents the tolerance, and the sixth band represents the temper­ature coeffi­cient.

Defini­tions of color bands

The color of the multiplier band represents multiples of 10, or the placement of the decimal point. For example: ORANGE (3) represents 10 to the third power or 1,000. The tolerance indicates, in a percen­tage, how much a resistor can vary above or below its value. A gold band stands for +/- 5%, a silver band stands for +/- 10%, and if there is no fourth band it is assumed to be +/- 20%. For example: A 100-Ohm 5% resistor can vary from 95 to 105 Ohms and still be considered within the manufa­ctured tolerance. The temper­ature coeffi­cient band specifies the maximum change in resistance with change in temper­ature, measured in parts per million per degree Centigrade (ppm/°C).
 

Resistor Band and Meaning

Example (from chart)

1. Look at the first resistor on the chart. In this case, the first color band is BROWN. Following the line down the chart you can see that BROWN represents the number 1. This becomes our first signif­icant digit.

2. Next, look at the second band and you will see it is BLACK. Once again, follow the line down to the bar scale; it holds a value of 0, our second signif­icant digit.

3. Next, look at the third band, the multip­lier, and you will see it is ORANGE. Once again, follow the line down to the bar scale; it holds a value of 3. This represents 3 multiples of 10 or 1000. With this inform­ation, the resistance is determined by taking the first two digits, 1 and 0 (10) and multip­lying by 1,000. Example: 10 X 1000 = 10,000 or 10,000 Ohms.

4. Using the chart, the fourth band (GOLD), indicates that this resistor has a tolerance of +/- 5%. Thus, the permis­sible range is: 10,000 X .05 = +/- 500 Ohms, or 9,500 to 10,500 Ohms.