Identification of Color-coded Resistor

Resistors with color bands are a practical way for users to determine their resistance value without the need for a multimeter. These color-coded markings are typically found on cylindrical resistors, such as carbon film, metal film, metal oxide film, fuse, and wire-wound resistors. The number of color bands varies depending on the resistor type, usually indicating either four, five, or six bands that represent its resistance value.

Color-coded resistors are among the most commonly used components in electronic circuits. They use colored bands painted around the resistor body to indicate their resistance value. The units used include ohms (Ω), kilo-ohms (kΩ), and mega-ohms (MΩ). For reference, 1 MΩ equals 1000 kΩ or 1,000,000 Ω.

Most color-coded resistors fall into two main categories: four-band and five-band types. Four-band resistors are more frequently used in general applications. In a four-band resistor, the first two bands represent significant digits, the third band is the multiplier, and the fourth band shows the tolerance. Five-band resistors offer more precision, where the first three bands are significant digits, the fourth is the multiplier, and the fifth represents the tolerance. Common tolerance indicators include gold (5%), silver (10%), brown (1%), and no color (20%). Occasionally, green may also be used to denote a 0.5% tolerance.

How to Identify a Four-Band Resistor

A four-band resistor uses four colored bands to show its resistance value. Starting from the left, the first band is the first digit, the second is the second digit, the third is the multiplier, and the fourth indicates the tolerance. If you're unsure which band is the first one, look for the fourth band, which is often gold or silver—other colors are rarely used in this position. This method applies only to four-band resistors.

Examples:

• Red, yellow, brown, gold: 24 × 10 = 240 Ω, tolerance 5%
• Green, red, yellow, silver: 52 × 10,000 = 520 kΩ, tolerance 10%

How to Identify a Five-Band Resistor

A five-band resistor provides greater accuracy by using five colored bands. The first three bands represent the significant digits, the fourth is the multiplier, and the fifth is the tolerance. For example, a resistor with red, red, black, black, and brown bands would read as 220 × 1 = 220 Ω with a 1% tolerance.

How to Identify a Six-Band Resistor

Some resistors have six color bands, with the first five following the same logic as a five-band resistor. The sixth band indicates the temperature coefficient, showing how the resistance changes with temperature. These are less common and are typically used in specialized applications requiring high stability and precision.