Resistance Color Coding Calculator

Resistance color coding is a vital concept in the field of electronics. This system uses colored bands on resistors to denote their resistance value, tolerance, and sometimes, reliability. This tutorial explains the associated calculations and formulas based on four color bands typically found on a resistor.

Resistance Color Coding Calculator
Resistance Color Coding Calculator Results
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Example Formula

The standard resistance value of a four-band resistor can be calculated using the following formula:

Resistance Value = (Band1 × 10 + Band2) × 10Band3 ± Band4%
  1. Band1: Represents the first significant figure.
  2. Band2: Represents the second significant figure.
  3. Band3: Represents the multiplier, indicating the power of ten to which the two significant figures should be multiplied.
  4. Band4: Represents the tolerance, indicating the precision of the resistor. If there is no fourth band, the default tolerance is ±20%.

Who wrote/refined the formula

The color coding system for resistors was standardized by the Electronic Industries Association (EIA) in the mid-20th century. The formula to calculate resistance based on color codes is a direct application of this standardization.

Real Life Application

Resistance color coding is widely used in the electronics industry. It is essential for identifying the resistance value of resistors used in a multitude of electronic devices, from simple circuits in educational settings to complex systems in aerospace technology.

Key individuals in the discipline

While there are no specific individuals associated with the concept of resistance color coding, the Electronic Industries Association (EIA) played a crucial role in standardizing the system. Their effort made it possible to have a globally recognized method to indicate the resistance value of resistors.

Interesting Facts

  1. Resistance color coding is not only used for resistors, but also for inductors and capacitors in some instances.
  2. The color coding system has made it possible to easily and quickly identify resistance values, significantly improving efficiency in electronics manufacturing and repairs.
  3. There's a mnemonic rhyme "Bad Boys Rave Our Young Girls But Violet Gives Willingly" to help remember the color sequence: Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White.


Understanding resistance color coding is fundamental to working with electronic circuits. It provides a standardized, efficient, and straightforward way to denote and decipher resistance values. From classrooms to advanced technological industries, this system remains a cornerstone of electronics.

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