Resistor Color Codes

Colored bands are used to identify the value of a resistor. Sometimes the colored bands are grouped close to one end of the resistor and with one single band located at the other end. But all colored bands can also be evenly spaced together closely to one end. The leading colored band is the band nearest to a lead wire.

Type of Color Code

4-band code: For low precision resistors, with tolerances 5%, 10%, or 20%, only two most significant digits are needed to represent the value of a resistor. The 4-band code rules are:

1. The first two bands are the most significant digits of the resistance value. The colored band represents the number of the significant digit. The first band is the first significant figure.

2. The third band is the "power of ten" multiplier by which the two significant digits to be multiplied. The colored band represents the number of the power or the index.

3. The forth band is the tolerance band. This band is either near the other end of wire lead or spaced away from the other bands. Gold colored band represents 5% tolerance and silver colored band represents 10% tolerance. While 20% tolerance resistors have no colored tolerance band, i.e. only 3 colored bands.

3-band code: For 20% resistors, the tolerance ring is colorless. And the three bands are calculated as the first three bands using in the 4-band rule, i.e. digit, digit, multiplier

5-band code: For high precision resistors, with tolerances 2%, 1%, or lower, three most significant digits are needed to represent the value of a resistor. The 5-band code rules are:

1. The first three bands are the most significant digits of the resistance value. The colored band represents the number of the significant digit. The first band is the first significant figure.

2. The forth band is the "power of ten" multiplier by which the three significant digits to be multiplied. The colored band represents the number of the power or the index.

3. The fifth band is the tolerance band. This band can be spaced away from the other bands or equally spaced as others.  The colored band represents tolerance percentage of the resistor.

Additional band: For special purpose resistors, an additional colored band is needed to represent the temperature coefficient or the reliability of a resistor.

1. The 6-band code for tight precision resistor: A sixth colored band is added to the 5-color band to represent the temperature coefficient of the resistor.

2. The 5-band military code for military purpose: A fifth colored band is added to the 5-color band to represent the reliability or failure rate of the resistor.

Color Code