Resistance Color Code Calculator
Ezekiel Tulagan
Color-coding is a method used to indicate the resistive value, tolerance, and temperature coefficient of resistors with low wattage rating because of their small size. Color bands are used because they can be easily and cheaply printed on a small electronic component. Color-coding is also used for capacitors, inductors and diodes.
When the resistor body surface is large enough, as in large wattage resistors, the resistance value, tolerance, and wattage are usually printed on the body of the resistor. Surface mounted resistors (SMD) use another coding system that uses alphanumeric codes printed on its surface instead of color codes.
In a three-band resistor, the first two bands represent the first two significant digits followed by one band for the multiplier. Since no tolerance band is available, the tolerance will always be 20%.
In a four-band resistor, which is the most common, the first two bands also represent the first two significant digits. The third band represents the multiplier. The fourth band represents the tolerance.
Tolerance is the percentage of error between the actual measured resistive value and the stated value. This is due to the manufacturing process and it is expressed as a percentage of its preferred value
A zero-ohm resistor is a resistor having a single black band. Its resistance is approximately zero and it is used to connect two traces on a printed circuit board (PCB). Is it used in automated PCB assembly where using the same equipment used to mount other resistors is easier than using a separate machine to install a wire jumper.
The following are tools to calculate the ohm value and tolerance based on resistor color codes, the total resistance of a group of resistors in parallel or in series, and the resistance of a conductor based on size and conductivity.
An electronic color code is a code that is used to specify the ratings of certain electrical components, such as the resistance in Ohms of a resistor. Electronic color codes are also used to rate capacitors, inductors, diodes, and other electronic components, but are most typically used for resistors. Only resistors are addressed by this calculator.
The color coding for resistors is an international standard that is defined in IEC 60062. The resistor color code shown in the table below involves various colors that represent significant figures, multiplier, tolerance, reliability, and temperature coefficient. Which of these the color refers to is dependent on the position of the color band on the resistor. In a typical four-band resistor, there is a spacing between the third and the fourth band to indicate how the resistor should be read (from left to right, with the lone band after the spacing being the right-most band). In the explanation below, a four-band resistor (the one specifically shown below) will be used. Other possible resistor variations will be described after.
In a typical four-band resistor, the first and second bands represent significant figures. For this example, refer to the figure above with a green, red, blue, and gold band. Using the table provided below, the green band represents the number 5, and the red band is 2.
The third, blue band, is the multiplier. Using the table, the multiplier is thus 1,000,000. This multiplier is multiplied by the significant figures determined from the previous bands, in this case 52, resulting in a value of 52,000,000 Ω, or 52 MΩ.
The fourth band is not always present, but when it is, represents tolerance. This is a percentage by which the resistor value can vary. The gold band in this example indicates a tolerance of 5%, which can be represented by the letter J. This means that the value 52 MΩ can vary by up to 5% in either direction, so the value of the resistor is 49.4 MΩ - 54.6 MΩ.
Coded components have at least three bands: two significant figure bands and a multiplier, but there are other possible variations. For example, components that are made to military specifications are typically four-band resistors that may have a fifth band that indicates the reliability of the resistor in terms of failure rate percentage per 1000 hours of service. It is also possible to have a 5th band that is the temperature coefficient, which indicates the change in resistance of the component as a function of ambient temperature in terms of ppm/K.
More commonly, there are five-band resistors that are more precise due to a third significant figure band. This shifts the position of the multiplier and tolerance band into the 4th and 5th position as compared to a typical four-band resistor.
On the most precise of resistors, a 6th band may be present. The first three bands would be the significant figure bands, the 4th the multiplier, the 5th the tolerance, and the 6th could be either reliability or temperature coefficient. There are also other possible variations, but these are some of the more common configurations.
Resistors are circuit elements that impart electrical resistance. While circuits can be highly complicated, and there are many different ways in which resistors can be arranged in a circuit, resistors in complex circuits can typically be broken down and classified as being connected in series or in parallel.
This tool is used to decode information for color banded axial lead resistors. Select the number of bands, then their colors to determine the value and tolerance of the resistors or view all resistors DigiKey has to offer.
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A resistor is identified by its pattern of color of bands. There are 4, 5 and 6 band resistors. To calculate the resistance of a resistor, you can select the appropriate color bands in the above resistor color code calculator.
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That might be a four-band, wire-wound resistor at 1 Ohm, 5% tolerance, with a fifth band for a specific purpose. Try the Resistor Color Code Calculator, again, with brown, black, gold, and gold in the 4-Band mode.
I settled on wire-wound because sometimes the wide band indicates that composition. The same color band code may apply, though, because I came across references to older resistors having a fifth band that indicated something other than the preceding resistance, multiplier, and tolerance.
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Electronic color codes serve as a standardized system for specifying the ratings of various electrical components, particularly the resistance of resistors in Ohms. While they are also employed for capacitors, inductors, diodes, and other electronic parts, their primary application remains with resistors.
Calculating the resistance of a resistor based on its color codes involves interpreting the values of the individual color bands. The standard resistor color code uses four bands, and sometimes a fifth band for the tolerance or temperature coefficient.
Overlooking the tolerance band is another common mistake. The tolerance band indicates the allowable percentage difference from the stated resistance value. Ignoring this band can result in choosing a resistor with an unacceptable level of tolerance.
A resistor with the color bands Yellow, Purple, Green, and Silver might appear to be 47 ohms (Yellow-Purple-Green), but if the silver tolerance band is disregarded, the actual tolerance might be wider than expected.
A resistor with the color bands Brown, Black, Red, Orange, and Brown might be mistaken for 10,000 ohms (Brown-Black-Red), but the temperature coefficient indicates a variation that should be considered.
Mastering resistor color codes requires attention to detail and an understanding of potential pitfalls. By being aware of common mistakes and learning from practical examples, you can confidently navigate the colorful world of resistors in your electronic projects.
If you want to find out the color bands for a value, use the tool on the left. Enter the value, select the multiplier (Ω, K or M), the desired precision and hit 'Display resistor' or ENTER. You can also type in resistor values in shorthand notation like 1k5, 4M7 or 100R.
3.) The first band can't be silver or gold, so if you hold such a resistor you'll know instantly where to start. Also, the 3rd color for 4-band resistors will be blue (106) or less and the 4th color for 5 band resistors will be green (105) or less, as basic resistor values range from 0.1 Ohm to 10 Mohms.
You should always attempt to work out the value, then check your result against a resistor value chart to see if it's listed there. If it isn't, then try reading it again starting from the other end and check again. This is a necessary step especially with five and six banded metal film resistors.
Our color code calculator runs this check automatically for you, and if the result is not a standard value, it will display a small tip. The warnings are there for your information only and do not always imply that the resistor is was read the wrong way -- see the notes below.
1.) The resistor color code and the EIA preferred values are internationally accepted standards, but some manufacturers have their own way of doing things. For example, many resistor manufacturers make every single value on the E24 list in 1% and 2% tolerance even though the practice makes little mathematical sense.
2.) Although the program was tested rigorously, it still may have a few bugs. Therefore, when in doubt (and when it's possible) don't hesitate to use your trusted, old friend -- the multimeter -- to double-check the critical components.
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