Bands encode resistance value and accuracy.
Colour bands encode resistance digits, multiplier and tolerance (brown 1, red 2, orange 3, … gold 5%, silver 10%). E-series (E12, E24, E96) define preferred values. Surface-mount parts use numeric codes.
Red-violet-orange-gold is 27 kΩ ±5%.
Colour codes are the way resistor values are read, and reading them wrong is a common cause of faulty builds.
Bands encode resistance value and accuracy.
Colour codes are the way resistor values are read, and reading them wrong is a common cause of faulty builds.
It gives the allowed deviation from the nominal value, such as 5 percent or 1 percent, so a 100 ohm part at 5 percent can read from 95 to 105 ohms.
Yes. A multimeter measures the actual resistance, which avoids misreading the bands.
Typical applications include identifying a resistor value from a bag of mixed parts, choosing a 1 percent tolerance resistor for a precision reference and checking the value of a missing label on a prototype board.
Study "Voltage and current dividers" first (topic 12 of 106 in Electrical Engineering). It covers the groundwork this topic builds on.
First two bands digits. Third band multiplier. Fourth band tolerance.
Red-violet-orange-gold is 27 kΩ ±5%.
The next topic is "Batteries and internal resistance", which builds directly on this one.
It is classed as Beginner in Electrical Engineering (topic 13 of 106). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.