Resistor Color Codes

A Resistor is an electrical component that resists the flow of electric current, reducing the current flow and voltage level. It converts electrical energy into heat energy, reducing the amount of current that can flow through the circuit.

Resistor Color Code is a standardized system used to indicate the value of a Resistor. It uses a series of colored bands to represent the value of the Resistor in terms of its resistance (in ohms), tolerance (in percentage), and temperature coefficient (in ppm/K).

A Resistor Color Code consists of 3, 4, 5, or 6 bands, with 4 bands being the most common.

• In a 3-band Resistor, the first and second bands represent the first and second digits of the resistance value, and the third band represents the multiplier.
  A 3-band 1k Ohm Resistor. (Brown/Black/Red)
• In a 4-band Resistor, the first and second bands represent the first and second digits of the resistance value, the third band represents the multiplier, and the fourth band represents the tolerance of the Resistor.
  A 4-band 1k Ohm Resistor with a tolerance of ± 0.01%. (Brown/Black/Red/Grey)
• In a 5-band Resistor, the first three bands represent the first three digits of the resistance value, the fourth band represents the multiplier, and the fifth band represents the tolerance of the Resistor.
  A 5-band 10k Ohm Resistor with a tolerance of ± 0.01%. (Brown/Black/Black/Red/Grey)
• In a 6-band Resistor, the first three bands represent the first three digits of the resistance value, the fourth band represents the multiplier, the fifth band represents the tolerance of the Resistor, and the sixth band represents the temperature coefficient.
  A 6-band 10k Ohm Resistor with a tolerance of ± 0.01% and a temperature coefficient of 10 ppm/K. (Brown/Black/Black/Red/Grey/Blue)

Calculating the Resistance Value from Band Color Codes

To calculate the resistance value of a Resistor, you can follow these steps:

1. Identify the digit bands: In a 3 or 4 band resistor, these are the first 2 bands, and in a 5 or 6 band resistor, these are the first 3 bands. For example, a brown band followed by a black band would indicate a resistor with a value of 10 Ω.
2. Identify the multiplier band: In a 3 or 4 band resistor, this is the 3rd band, and in a 5 or 6 band resistor, this is the 4th band. For example, a red band would indicate a multiplier of 100.
3. Calculate the resistance value: Multiply the two or three digits from step 1 by the multiplier from step 2. For example, a 3 band resistor with a brown band (1) followed by a black band (0) and a red band (100) would indicate a resistor with a value of 10 x 100 Ω = 1,000 Ω.

Calculating Resistor Band Color Codes from Resistance Value

To calculate the band color codes of a Resistor, you can follow these steps:

1. Identify the significant figures of the resistance value: For a 3 or 4 band resistor, take the first two significant figures, and for a 5 or 6 band resistor, take the first three significant figures. Some examples:
   1. 100 Ohm: The first two significant figures are 1 and 0 (Brown-Black). The first three (for a 5 or 6 band resistor) are 1, 0, and 0 (Brown-Black-Black).
   2. 0.23 Ohm: The first two significant figures are 2 and 3 (Red-Orange). The first three (for a 5 or 6 band resistor) are 2, 3, and 0 (Red-Orange-Black).
   3. 442,000 Ohm: This resistor has 3 significant figures, so it cannot be represented with a 3 or 4 band resistor. For a 5 or 6 band resistor, the significant figures are 4, 4, and 2 (Yellow-Yellow-Red).
2. Calculate the multiplier: Calculate the number with which the significant figures calculated in the last step must be multiplied to obtain the resistance value. Some examples:
   1. 100 Ohm: For a 3 or 4 band resistor, the significant figures are 10, which must be multiplied by 10 = 10 ^ 1 (1 = Brown) to obtain 100 Ohm. For a 5 or 6 band resistor, the significant figures are 100, which must be multiplied by 1 = 10 ^ 0 (0 = Black) to obtain 100 Ohm.
   2. 0.23 Ohm: For a 3 or 4 band resistor, the significant figures are 23, which must be multiplied by 0.01 = 10 ^ -2 (-2 = Silver) to obtain 0.23 Ohm. For a 5 or 6 band resistor, the significant figures are 230, which must be multiplied by 0.001 = 10 ^ -3 (-3 = Pink) to obtain 0.23 Ohm.
   3. 442,000 Ohm: For a 5 or 6 band resistor, the significant figures are 442, which must be multiplied by 1000 = 10 ^ 3 (3 = Orange) to obtain 442,000 Ohm.
3. Identify the Tolerance and Temperature Coefficient: Identify the tolerance and temperature coefficient of the resistor and look up its corresponding band color in the color code chart above. For example, a 5% tolerance resistor would have the color Gold and a 50 ppm/K Temperature Coefficient resistor would have the color Red.
4. Join the colors: Finally, join the colors of the significant figures, the multiplier, the tolerance, and the temperature coefficient to obtain the band color codes of the resistor.

Common Resistors and their Color Codes