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Author:admin Date: 2025-01-20 06:23 Views:80
Learn how to read resistor color codes in 1 minute
When you have a resistor in your hand, do you want to know its resistance value at first sight? Coincidentally, this article can just help you, I believe you can find the answer after reading this article. Let’s go!
Resistor Color Code Introduction
First of all, let’s briefly explain what resistor color code is? It is the process of marking the resistance value, multiplier, tolerance and temperature coefficient of a resistor with different colors to help the user to quickly identify the value and calculate the resistance value with simple calculations.
The marking method was first introduced by the Radio Manufacturers Association (RMA) in the 1920s and has since been adopted by several international organizations. In 2019, the International Electrotechnical Commission (IEC) published the IEC IEC 60062 Consolidated version as a globally accepted specification.
In addition, the use of color codes has been extended to small electronic components such as capacitors, diodes and inductors.
Basic Rules for Resistor Color Codes
Before we start the calculation, we need to know the meaning and location of each color, and the corresponding color code.
1. Resistor color code chart
In the standard IEC 60062:2016, the color pink has been added for coding multipliers 10-³, see the table below for details.
| Color | Digit | Multiplier | Tolerance | Temperature Coefficient (ppm/°C) |
|---|---|---|---|---|
| Black | 0 | 100 (×1) | — | 250 |
| Brown | 1 | 101 (×10) | ±1% | 100 |
| Red | 2 | 102 (×100) | ±2% | 50 |
| Orange | 3 | 103 (×1,000) | — | 15 |
| Yellow | 4 | 104 (×10,000) | — | 25 |
| Green | 5 | 105 (×100,000) | ±0.5% | 20 |
| Blue | 6 | 106 (×1,000,000) | ±0.25% | 10 |
| Violet | 7 | 107 (×10,000,000) | ±0.1% | 5 |
| Gray | 8 | 108 (×100,000,000) | ±0.05% | — |
| White | 9 | 109 (×1,000,000,000) | — | — |
| Gold | — | 10-1 (×0.1) | ±5% | — |
| Silver | — | 10-2 (×0.01) | ±10% | — |
| Pink | — | 10-3 (×0.001) | — | — |
2. Resistor color band position and meaning
Based on the table above we will elaborate on what these colors represent.
– Valid Numerals
Regardless of the number of bands on the resistor, the first and second bands are always significant digits, indicating the basic magnitude of the resistance value. In the case of 5-band resistors and 6-band resistors, the third band is also an effective number, which is used to define the resistance value more precisely.
– Multiplier band
The multiplier band determines the order of magnitude of the significant digit, and the resistance value is derived by multiplying with the significant digit. The last of the 3-bands is the multiplier band. In the 4-band and-5 bands, the multiplier band always remains in the penultimate row. For the 6-band, the multiplier band is in the penultimate band.
– Tolerance band
The tolerance band indicates the extent to which the resistance value may deviate from the nominal value during the manufacturing process and is expressed as a percentage. 4-band and 5-bands always have the tolerance band on the last line. Tolerance bands for 4-band and 5-bands are always on the last line, while for 6-bands, the tolerance band is on the penultimate band. 3-band resistors do not have a tolerance band.
– Temperature coefficient band
Appears only in 6 band resistors and is used to indicate the sensitivity of the resistance value to changes in temperature in ppm/K.
– Special Cases:
In addition to the cases described above, some special bands may represent failure rates or other variations. Military applications, or extreme environments such as space, deep sea equipment, etc., are additionally marked to indicate characteristics such as resistance to high temperatures, corrosion, or radiation.
Reading and Calculating Resistance Values
Once we understand the basic rules above, we can start reading the colors on the resistor.
1. Read order
– Before reading a color code, it is important to distinguish between the “head” and “tail” of the resistor, where we consider the end of a concentration of multiple bnads to be the head. The gold and silver tolerances are usually on the tail, and there is a large distance between them and the band we see as the head.
– After determining the head and tail, view the bands from left to right and record the values in conjunction with the color code table above.
2. Calculate the formula
Recorded values, according to the following formula to calculate, you can get the answer you want.
Resistance value of resistor = (significant digit) × (power of 10).
Actual value range of tolerance = Nominal value (resistance value of resistor) ± (nominal value × tolerance percentage).
3. Examples of different number of bands
In order for you to learn this calculation method more easily and clearly, the following is an example of calculation for different bands:
3 band resistor
This model is suitable for users who do not need too much precision, the default tolerance is usually ±20%, example: Red-Orange-Yellow = 23 × 10,000 = 230kΩ. The actual value range of tolerance = 230kΩ ± (230kΩ × 20%) = 230kΩ ± 46kΩ (184kΩ to 276kΩ).
4 band resistor
The most common resistor used for general accuracy requirements. 1k resistor colour code example: Brown-Black-Red-Gold = 10 × 100 = 1kΩ ±5%. Actual value range of tolerance = 1kΩ ± (1kΩ × 5%) = 1kΩ ± 50Ω (950Ω to 1050Ω).
5 band resistor
Add an effective digit band to improve accuracy. 10k resistor colour code example: brown-black-black-orange-brown = 100 × 1,000 = 10kΩ ±1%. Actual value range of tolerance = 10kΩ ± (10kΩ × 1%) = 10kΩ ± 100Ω (9,900Ω to 10,100Ω).
6 band resistor
Adding a band to a 5-band resistor represents a temperature coefficient. Example: Orange-Red-Brown-Brown-Green-Red = 321 × 10 Ω = 3.21kΩ ±1%, actual value range of tolerance = 3.21kΩ ± (3.21kΩ × 1%) = 3.21kΩ ±32.1Ω (3.1779kΩ to 3.2421kΩ). Temperature coefficient 50ppm/°C.
Tips:If there is no color code on the resistor, check the resistor model number with the manual provided by the manufacturer to confirm the resistance value. If the color code on the resistor is faded, blurred, etc., you can use a multimeter to test the resistor to obtain the resistance value.
Resistor Standardized Series
IEC standards classify resistor resistance values into the E3, E6, E12, E24, E48, E96 and E192 series. This is used to ensure compatibility in the manufacture, sale and use of resistors.
Please refer to the following table for details.
| Series | Values per Decade | Tolerance | Example Values | Application Scenarios |
|---|---|---|---|---|
| E3 | 3 | >20% | 1.0, 2.2, 4.7 | Non-critical designs |
| E6 | 6 | ±20% | 1.0, 1.5, 2.2, 3.3, 4.7, 6.8 | Common circuit designs, low precision requirements |
| E12 | 12 | ±10% | 1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3 | General electronic designs |
| E24 | 24 | ±5% | 1.0, 1.1, 1.2, 1.3, 1.5, 1.6, 1.8 | High precision circuit designs |
| E48 | 48 | ±2% | 1.0, 1.05, 1.1, 1.15, 1.21, 1.27 | Precision applications |
| E96 | 96 | ±1% | 1.0, 1.02, 1.05, 1.07, 1.1, 1.13 | High precision and specific needs |
| E192 | 192 | ±0.5% and higher | 1.0, 1.01, 1.02, 1.03… | Ultra-high precision applications, such as instrumentation design |
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Frequently Asked Questions
- How to memorize the color code sequence quickly?
Use mnemonics such as “Big Boys Race Our Young Girls But Violet Generally Wins”.
- What is the purpose of a zero ohm resistor?
There is only one black band, used as PCB jumper connection, similar to the function of wires.
- What about the application of 6 Band resistors?
Due to its added temperature coefficient band, it is ideal for high precision measurements and scenarios that are sensitive to temperature changes.
- What colors are used to represent high voltage resistors?
Yellow or grey instead of metal band, avoid using metal material, because metal material is not resistant to high temperature and other reasons.