Resistor color codes use colored bands to indicate resistance value, tolerance, and temperature coefficient. This system allows resistors to be identified regardless of installation orientation. The coding follows an internationally standardized color-to-number mapping.
4-Band: Basic type. First two bands are digits, third is multiplier, fourth is tolerance (±5% or ±10% typical).
5-Band: Higher precision with three significant digits. First three are digits, fourth is multiplier, fifth is tolerance (±1% typical).
6-Band: Adds a temperature coefficient band (TCR in ppm/°C) for precision circuits requiring thermal stability.
A resistor color code uses colored bands to indicate resistance value, tolerance, and temperature coefficient. There are 4-band, 5-band, and 6-band resistors. 4-band: 2 digits + multiplier + tolerance. 5-band: 3 digits + multiplier + tolerance (higher precision). 6-band: adds temperature coefficient.
4-band resistor reading: First two bands are digits, third is multiplier (power of 10), fourth is tolerance. Example: Brown(1), Black(0), Red(×10²), Gold(±5%) = 10 × 100 = 1000Ω = 1kΩ, ±5%. Color coding: Black 0, Brown 1, Red 2, Orange 3, Yellow 4, Green 5, Blue 6, Violet 7, Gray 8, White 9.
5-band resistors have higher precision with three significant digits. First three bands are digits, fourth is multiplier, fifth is tolerance. Example: Brown(1), Black(0), Black(0), Brown(×10¹), Brown(±1%) = 100 × 10 = 1000Ω = 1kΩ, ±1% precision.
Common tolerance codes: Brown ±1% (precision), Red ±2%, Gold ±5%, Silver ±10%. No band means ±20%. For 6-band resistors, the 6th band shows temperature coefficient: Brown ±100ppm/°C, Red ±50ppm/°C, Blue ±10ppm/°C, etc.
Mnemonic: Black(0), Brown(1), Red(2), Orange(3), Yellow(4), Green(5), Blue(6), Violet(7), Gray(8), White(9). A popular English mnemonic: 'Big Boys Race Our Young Girls But Violet Generally Wins.' Practice with a few resistors and it becomes second nature.
Power rating (e.g., 1/4W, 1/2W, 1W) is separate from resistance value. It indicates the maximum power the resistor can safely dissipate. Actual power P = I²R must stay below the rating to prevent overheating. Higher power resistors are physically larger but use the same color code system.