How to Calculate Resistor Value 

Calculate Resistor Value 

How to Calculate Resistor Value? There are two ways to find out the resistance value of a resistor. The first is based on the color band and the second value is listed directly on the body of the resistor. The most basic thing to know the resistor color value is to remember the resistor value table. 

1. Based on Resistor Color Table

In Figure below is a resistor color code chart from 4 bands to 6 bands of color. In addition to determining the resistance value, the color code of the resistor in the 6th ring of the color band is also used to determine the Temperature Coefficient of Resistance (TCR) of a resistance. The unit of this TCR is ppm/°C. (parts per million per degree Cetrigrade).

Resistance Color Table

You have to memorize the color table because it will be widely used in electronic design and manufacturing.

a. How to Read the Bracelet Color Code Resistor Value  

You have to remember the resistor value table code above. The priority to remember is the Color and Number column because it already represents the multiplication column.

Take a look at the multiplication column, we can replace the multiplication term with “Number of Zeros”.

Look at the brown color, the value is 1. Chocolate is worth 1, meaning that in the bracelet/column the zero multiplier is one.

Red has a value of 2, zero is two and so on and this only applies in the multiplier column.

If you are still confused, here I will give two examples of how we can read the color band on a resistor to find out what the resistance value of the resistor is.

b. First Example

Here in Figure 1 there is a resistor that I provide. This resistor has 4 colored bands on the body of the resistor. 

How to Calculate Resistor Value 

Please review the color chart to see the value of the bracelet color. How to calculate resistor color is:

Brown, Black, Orange and Gold

      1 ,        0   x  1.000    and  ±5%.

Result is: 10.000 Ohm ±5%

(How to read : 10.000 atau 10K Ohm with ±5%);

c. Second Example

How to Calculate Resistor Value 

How to read the second example resistor is:

Orange, Orange, Red and Gold.

      3,        3   x  100    and  ±5%.

Results is : 3.300 Ohm ±5%

(How to read  : 3.300 or 3K3 Ohm with ±5%);

2. How to Read SMD Resistor Value

To read the SMD resistor is easier than the resistor that has a color band. Figures 4 and 5 are examples of SMD resistors. Generally SMD resistors have the value listed on the body. Take a look at the following picture:

a. First Example

How to Calculate Resistor Value 

Examples of SMD resistors read 3,300 Ohms or 3K3 Ohms or 3.3K Ohms

b. Second Example

How to Calculate Resistor Value 

Examples of SMD Resistors read 100 Ohm.

I hope this tutorial is useful.

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