Calculate resistor values from color codes, determine parallel/series resistance, and calculate conductor resistance. Supports 3-6 band resistors with comprehensive color code decoding.
An electronic color code is a standardized system used to specify the ratings of electrical components, particularly resistors. This coding system allows engineers and technicians to quickly identify resistance values, tolerances, and other important specifications without requiring additional measuring equipment.
The resistor color code is an international standard defined in IEC 60062. This system uses colored bands to represent significant figures, multipliers, tolerance, reliability, and temperature coefficient values. The position of each color band determines its meaning, with typical spacing between the main value bands and the tolerance/coefficient bands.
For 5-band resistors: (Band₁ × 100 + Band₂ × 10 + Band₃) × Multiplier
Significant Figures: The first two (or three) bands represent the main digits of the resistance value. For example, if you see green (5) and red (2), this gives you the base number 52.
Multiplier: The multiplier band determines how many zeros to add to your base number, or what power of 10 to multiply by. A blue multiplier represents 10⁶ (1,000,000), so 52 × 1,000,000 = 52,000,000Ω or 52MΩ.
Tolerance: The tolerance band indicates the precision of the resistor value. A gold band represents ±5% tolerance, meaning the actual resistance can vary by up to 5% from the stated value in either direction.
3-Band Resistors: Basic resistors with two significant figures and a multiplier. These have ±20% tolerance and no tolerance band.
4-Band Resistors: Most common type with two significant figures, multiplier, and tolerance band. Typical tolerance values are ±5% (gold) or ±10% (silver).
5-Band Resistors: Precision resistors with three significant figures, multiplier, and tolerance. These offer higher precision with tolerances as low as ±1% or ±0.5%.
6-Band Resistors: Ultra-precision resistors that include three significant figures, multiplier, tolerance, and temperature coefficient. The temperature coefficient indicates how the resistance changes with temperature (measured in ppm/K).
| Color | Significant Figures (1st, 2nd, 3rd Band) |
Multiplier | Tolerance | Temperature Coefficient |
|---|---|---|---|---|
| Black | 0 | × 1 | - | 250 ppm/K |
| Brown | 1 | × 10 | ±1% | 100 ppm/K |
| 2 | × 100 | ±2% (G) | 50 ppm/K (R) | |
| 3 | × 1K | ±0.05% (W) | 15 ppm/K (P) | |
| 4 | × 10K | ±0.02% (P) | 25 ppm/K (Q) | |
| 5 | × 100K | ±0.5% (D) | 20 ppm/K (Z) | |
| 6 | × 1M | ±0.25% (C) | 10 ppm/K (Z) | |
| 7 | × 10M | ±0.1% (B) | 5 ppm/K (M) | |
| 8 | × 100M | ±0.01% (L) | 1 ppm/K (K) | |
| 9 | × 1G | |||
| × 0.1 | ±5% (J) | |||
| × 0.01 | ±10% (K) | |||
| ±20% (M) |
Resistors are circuit elements that impart electrical resistance. While circuits can be highly complicated, and there are many different ways in which resistors can be arranged in a circuit, resistors in complex circuits can typically be broken down and classified as being connected in series or in parallel.
When resistors are connected in parallel, each resistor has the same voltage across it. The total resistance is less than the smallest individual resistance.
The total resistance of resistors in parallel is equal to the reciprocal of the sum of the reciprocals of each individual resistor. Refer to the equation below for clarification:
| Rtotal = |
|
|||||||||||||||||||||||||||||||||||||
When resistors are connected in series, the current through each resistor is the same, but the voltage across each resistor varies based on its resistance.
The total resistance of resistors in series is simply the sum of the resistances of each resistor. Refer to the equation below for clarification:
Rtotal = R1 + R2 + R3 ... + Rn
| R = |
|
Where:
L is the length of the conductor
A is the cross-sectional area of the conductor
C is the conductivity of the material