Color Code Reference
Digit colors: Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Gray=8, White=9. Multipliers: Black=×1, Brown=×10, Red=×100, Orange=×1k, Yellow=×10k, Green=×100k, Blue=×1M, Gold=×0.1, Silver=×0.01. Tolerance: Gold=±5%, Silver=±10%, Brown=±1%, Red=±2%.
Frequently Asked Questions
For a 4-band resistor: Band 1 = first digit, Band 2 = second digit, Band 3 = multiplier (power of 10), Band 4 = tolerance. For 5-band: Bands 1-3 = three digits, Band 4 = multiplier, Band 5 = tolerance. Multiply the digit portion by the multiplier to get the resistance in ohms.
Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Gray=8, White=9. For multipliers: Black=×1, Brown=×10, Red=×100, Orange=×1k, Yellow=×10k, Green=×100k, Blue=×1M, Gold=×0.1, Silver=×0.01. For tolerance: Brown=±1%, Red=±2%, Gold=±5%, Silver=±10%.
Resistors are manufactured in standard E-series values to cover the full resistance range with predictable tolerances. E12 (12 values per decade) is for 10% tolerance resistors; E24 (24 values) for 5% tolerance; E96 (96 values) for 1% tolerance. This is why you find 4.7kΩ and 22kΩ but not 5kΩ or 20kΩ as standard values.
Tolerance is the maximum percentage by which a resistor's actual value can differ from its stated value. A 1kΩ ±5% resistor can be anywhere from 950Ω to 1050Ω. Lower tolerance (1%, 0.1%) resistors are used in precision applications; 5-10% tolerances are fine for most general-purpose circuits.
The ohm symbol is Ω (Greek letter omega). Resistances are expressed in ohms (Ω), kilohms (kΩ = 1,000Ω), megohms (MΩ = 1,000,000Ω), and occasionally gigaohms (GΩ). On schematics, resistance is sometimes written as R: 4k7 means 4.7kΩ, 10R means 10Ω.
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