The resistor color code revealed!
Standard resistor values are marked with a color code. The following table shows the code. Depending on the position of the stripe it can mean a number value, a multiplier, or a tolerance. After the table, I will explain what that means. Learn this table. It will pay off handsomely knowing how to read parts values. The same basic scheme is used for many other types of components. And, don't worry, after some use, it will become second nature. You will eventually see, not colors, but numbers! Trust me!
In a four band color code, the most popular type, the first two bands are digits, and the third is the multiplier. In a 5 band code, there are three digit bands, and the fourth is the multiplier. In both schemes, the last band is the tolerance. Another code, called the 6 band code, is the same as the five band, but there is an additional color placed after the tolerance to denote temperature co-efficient.
For the 4-Band code:(most popular) From left to right, the first and 2nd bands are the two significant digits. The third is the multiplier, although you can think of it as just adding that many zeros.(For example, red, green, orange, would be a 2, a 5, and 3 zeros = 25,000 ohms). The fourth band is the tolerance Gold=5%, Silver=10%, Red=2%, Brown=1%. No band used to mean 20%, but that is rare nowadays. Each tolerance level has a different standard set of values. The values were mainly selected for use in voltage dividers to obtain a certain ratio. That is the reason for some of the 'odd' ones. 1% resistors used to be called precision resistors. Many of those have the value actually printed on them.
For the 5-Band code: From left to right, the first, second and 3rd bands are the three significant digits. The fourth is the multiplier, The fifth band is the tolerance Gold=5%, Silver=10%, Red=2%, Brown=1%.
The six band code is the same as five with the addition of the 6th band for temperature coefficient.