Resistance is a passive component commonly used to restrict electrical current. This article explains resistor color coding and how to measure resistance value . Each resistance follows a color coding scheme and its values are determined by decoding the colors marked on it. If you look at any resistance, you will find some colored bands on it, which serve to identify its value.
A resistor will have three to six colored bands. A set of ten colors is used to represent the resistance value. Each color represents a numeric digit from 0 to 9. Two additional colors are generally used to represent the multiplier of tolerance values.
Resistor color code for six (6) color band resistor
Fig. 1: Table listing color coding for 6-band resistors
Suppose we have a six-band resistance with the following color code representing the first to the last band, respectively:
Green Black Blue Brown Gold Red
Step 1: The first color represents the first significant digit. In this case, 5 corresponds to Green according to the table.
Step 2: The second color represents the second significant digit. In this case, it is 0 corresponding to Black according to the table.
Step 3: The third color represents the third significant digit. In this case, 6 corresponds to Blue according to the table.
So far the value can be represented as 506
Step 4: The fourth color represents the multiplier, that is, it represents the number by which the value formed by the first three digits needs to be multiplied to obtain the resistance value. In this case, 10 1 = 10 corresponding to Brown according to the table.
Therefore the resistance value is:
506 x 10 = 5060 ohms = 5.06K ohms
Step 5: The fifth digit represents the tolerance. Tolerance gives an indication of the extreme variation that can occur in the resistance value. It is represented as a percentage of the original value. In this case it is ± 5% corresponding to Gold.
Step 6: The last digit represents the temperature coefficient. The temperature coefficient tells us the change in resistance value with temperature. It is usually expressed as ppm/(degree Celsius). In this case, 50 corresponds to RED.
Therefore, the resistance value in this case is 5.06K ohm with a tolerance of ± 5% and 50ppm/degree C.
Note: The color value corresponding to any digit that is not given in the table is never used for that specific digit.
Resistor color code for 5-color band resistor
Resistor color code for five (5) color band resistor
Fig. 2: Table listing color coding for 5-band resistors
Suppose we have a five-band resistance with the following color code representing the first to the last band, respectively:
Green Black Blue Brown Gold
Step 1: The first color represents the first significant digit. In this case, 5 corresponds to Green according to the table.
Step 2: The second color represents the second significant digit. In this case, it is 0 corresponding to Black according to the table.
Step 3: The third color represents the third significant digit. In this case, 6 corresponds to Blue according to the table.
So far the value can be represented as 506
Step 4: The fourth color represents the multiplier, that is, it represents the number by which the value formed by the first three digits needs to be multiplied to obtain the resistance value. In this case, 10 1 = 10 corresponding to Brown according to the table.
Therefore the resistance value is:
506 x 10 = 5060 ohms = 5.06K ohms
Step 5: The fifth digit represents the tolerance. Tolerance gives an indication of the extreme variation that can occur in the resistance value. It is represented as a percentage of the original value. In this case it is ± 5% corresponding to Gold.
Therefore, the resistance value in this case is 5.06K ohm with a tolerance of ±5%
Note: The color value corresponding to any digit that is not given in the table is never used for that specific digit.
Resistor color code for 4-color band resistor
Resistor color code for four (4) color band resistor
Fig. 3: Table listing color coding for 4-band resistors
Suppose we have a four-band resistance with the following color code representing the first to last band, respectively:
Green Black Blue Gold
Step 1: The first color represents the first significant digit. In this case, 5 corresponds to Green according to the table.
Step 2: The second color represents the second significant digit. In this case, it is 0 corresponding to Black according to the table.
Step 3: The third color represents the multiplier, that is, it represents the number by which the value formed by the first three digits needs to be multiplied to obtain the resistance value. In this case, 10 6 = 1000000 corresponds to Brown according to the table.
Therefore the resistance value is:
50×10 6 = 50000000 ohms = 50M ohms
Step 4: The fourth digit represents the tolerance. Tolerance gives an indication of the extreme variation that can occur in the resistance value. It is represented as a percentage of the original value. In this case it is ± 5% corresponding to Gold.
Therefore, the resistance value in this case is 50M ohm with a tolerance of ±5%
Note: The color value corresponding to any digit that is not given in the table is never used for that specific digit.
Resistor color code for 3-color band resistor
Resistor color code for three (3) color band resistor
The color coding scheme for resistors with three color bands is exactly the same as that for four color bands, with the difference that the tolerance is 20% by default.
The first color represents the first significant digit, the second color the second significant digit and the third color the multiplier with a tolerance of 20%.