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. The Gold or Silver band is always placed to the right. Use our 4 Band Resistor Color Code Calculator online tool to calculate the information for color banded axial lead resistors of 4 band. Select the number of bands, then their colors to determine the value and tolerance of the resistors.
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).
The number of bands is important because the decoding changes based upon the number of color bands. For the 4 band resistor:Four Bands are
Band 1 – First significant digit
Band 2 – Second significant digit
Band 3 – Multiplier
Band 4 – Tolerance
Resistance=(First Significant Digit . Second Significant Digit) * Multiplier ± Tolerance %
|First Digit||Second Digit||Multiplier||Tolerance||Color|
|2||2||2 zero||2 %||Red|
|x 0.1||5% Gold|
|x 0.01||10% Silver|
Resistors are never the exact value that the color codes indicate.Therefore manufacturers place a tolerance color band on the resistor to tell you just how accurate this resistor is made. It is simply a measurment of the imperfections. Gold means the resistor is within 5% of being dead-on accurate. Silver being within 10% and no color band being within 20%. To determine the exact range that the resistor may be, take the value of the resistor and mutiply it by 5, 10, or 20%. That is the number that the resistor may go either way.
Example: A 1,000 Ohm resistor with a gold band maybe any value between 950 to 1050 Ohms.
Example: A 22,000 Ohm resistor with a silver band maybe any value between 19,800 and 24,200 Ohms.
Just a few common questions to help you out.
Question: Which side of the resistor do I read from?
Answer: The Gold or Silver band is always set to the right, then you read from left to right. Sometimes there will be no tolerance band. Simply find the side that has a band closest to a lead and make that the first band.
Question: Sometimes the colors are hard to make out. How do I make certain what the value of the resistor really is?
Answer: Occasionally the colors are jumbled or burnt off. The only way to read it then is with a multimeter across the leads.