Color Coding and Markings

The following are electronic components that needs to be decoded in order identify its internal values.

• RESISTOR

One distinct feature of this resistance - giving component is the way its value is determined. It uses a set of colors which follows a code for its assumed resistance. This set of colors are assigned as color bands and together they specify the; 

• resistance value, 

• multiplier,

• tolerance rate, (this will determine the minimum and maximum operational resistance value of a resistor)

• temperature coefficient rate.

Resistor decoding examples:

Color Codes: 1st Band 2nd Band 3rd Band

  Red   Yellow     Brown

Equivalent Value:        2     4       x10

Computation:

24 x 10 = 240 ohms (Ω) - actual resistance value

Take Note; that in a three color coded resistor, it is always assumed that it has a tolerance value of ± 20%.

Getting the Minimum and Maximum Tolerance Value:

Max. Tolerance = Actual Value + 20% of Actual Resistance Value

240 Ω       +      48      =       288 Ω

Min. Tolerance = Actual Value - 20% of Actual Resistance Value

    240 Ω       -      48      =       192 Ω

Color Codes: 1st Band 2nd Band 3rd Band 4th Band

Green     Blue   Orange           Gold

Equivalent Value:        5   6            x1000     ± 5%

Computation:

56 x 1000 = 56 000 ohms (Ω) or 56 kilo ohms (KΩ) - actual resistance value

Getting the Minimum and Maximum Tolerance Value:

Max. Tolerance = Actual Value + 5% of Actual Resistance Value

56 000 Ω       +      11 200      =       67 200 Ω or 67.2 KΩ 

Min. Tolerance = Actual Value - 5% of Actual Resistance Value

    56 000 Ω       -      11 200      =       44 800 Ω or 44.8 KΩ

• CAPACITOR

Only small size capacitors like ceramic, mylar, film and some other specialized capacitor has numerical codes and markings that needs to be decode.  Some capacitors uses alphanumeric codes and markings. These codes and markings specify the; 

• capacitance value,

• multiplier,

• tolerance rate,

• operating and/or breakdown voltage. 

The value of this capacitors always expressed in picofarad (pF). 

The most common capacitor code uses a first digit, second digit, and multiplier scheme: 

Example:

•  223J = 22 x 1000 pF = 22 000 pF = 22 nF = .022 µF 5% Tolerance 

•  151K = 15 x 10 pF = 150 pF = .15 nF = .00015 µF 10% Tolerance 

In the case of diodes, transistors, and IC's, you can take note of its part number printed in the components body and search for its datasheet. The datasheet will give all necessary information you needed.