How To Calculate or Read Resistor Value And Color Code Table

By | September 2, 2021

Resistors consist of two forms, Axial / Radial Components and Chip Components. The difference for the Axial / Radial Component is that the resistor value is color coded so that we can find out its value from that color. As for the chip component, the value consists of a certain code so that it is easier to find out.

Resisitor Colour

 

Calculating resistors can also be done using a measuring device called an Ohm Meter or MultiMeter.

How to Read Resistors

1. Calculating Resistor Based on Numeric Code

Calculating Chip components is easier than Axial Components which use color codes on their bodies because the Chip Components use numbers, so they are easier to understand.

Example :

The numeric code written on the chip resistor component body is 3 3 2
How to read it
1st digit = 3
2nd digit = 3
3rd digit = 00 ( 2 sums of 0) or 102
Then the value is 3300 Ohms or 3.3 Kilo Ohms

Another calculation example:

222 → 22 * ​​10² = 2,200 Ohms (2.2 Kilo Ohms)
103 → 10 * 10³ = 10,000 Ohms (10 Kilo Ohms)
334 → 33 * 104 = 330,000 Ohms (330 Kilo Ohms)

There are also those who use a numeric code as below:
(Writing R indicates the presence of a decimal comma)
4R7 = 4.7 Ohms
0R22 = 0.22 Ohm
The explanation of the formula above is:
Ohm = O
Kilo Ohms = KO
Mega Ohms = MO
1,000 Ohms = 1 KO
1,000,000 Ohms = 1 MO
1,000 kilo Ohms = 1 MO

2. Calculating Resistors by Color Code

Resistor in the form of Axial color code is on the body of the resistor in the form of a bracelet.
Generally there are 4 Bracelets on the Resistor body, but there are also 5
Gold and Silver bracelets are located further from the other color bracelets as a sign of the last bracelet. This last bracelet is the tolerance value for the relevant resistor value.

The following is a table of colors in the resistor body. For gold and silver bracelets are located further than other colors. See the color table below:

resiistor color code

3. Calculating resistors with 4 colored bands

4 band resistor color code

 

 

First Band color code  (Brown)
Second Band color code (Black)
Third Band color code (Red) = 00 or 102(10n)
Fourth Band color code (Gold) = Tolerance of Resistor value

Example :
First Band  : Brown = 2
Second Band : Black = 0
Third Band : Red = 2 zeros behind the second Band number or multiply by 102
Fourth Band: Gold  = ± 5% tolerance
So, the resistor value is 10 * 102 = 1,000 Ohms or 1 K Ohm with a tolerance of ± 5%.

4. Calculations for resistors with 5 colored bands

5 band resistor color code

 

Enter the number from the Band color code to one (first)
Enter the number from the color code of the second Band
Enter the number of the third Band color code
Enter the Number of zeros from the fourth Band color code or raise the number to the power of 10 (10n)
Fifth Band color code = Tolerance of Resistor value

Example :

First Band  : Red = 2
Second Band : Green = 5
Third Band: Yellow = 4
Fourth Band: Black = 0 zeros behind the second ring number or multiply by 100
Fifth Band: Brown = ± 1% tolerance
So, the value of the Resistor is 254 * 100 = 254 Ohms (with a tolerance of ± 1%.)

How to calculate Tolerance
2.200 Ohm with 5% Tolerance =
2200 – 5% = 2.090
2200 + 5% = 2.310
This means that the value of the resistor will be between 2.090 Ohm ~ 2.310 Ohm