Resistor Color Code Calculator

This calculator helps you determine the resistance value of color-coded resistors. Resistors are fundamental components in electronics that limit current flow, divide voltages, and provide specific resistance in circuits.

Calculated Values:

Resistance: -
Tolerance: -
Temp. Coefficient: -

Understanding Resistors

How Resistor Color Coding Works

Resistors use colored bands to indicate their resistance value, tolerance, and sometimes temperature coefficient:

  • First 2-3 bands: Significant digits of the resistance value
  • Next band: Multiplier (power of 10)
  • Next band: Tolerance (how much the actual value may vary)
  • 6th band (if present): Temperature coefficient (how much resistance changes with temperature)

Common Resistor Types

Carbon Composition

Oldest type, used in high-energy applications, typically 5-20% tolerance

Carbon Film

Better stability than carbon comp, 2-5% tolerance

Metal Film

Most common, high precision (1% or better), low noise

Wirewound

For high power applications, very precise but inductive

SMD (Surface Mount)

Small rectangular components with printed codes instead of color bands

Voltage Divider Example

A voltage divider uses two resistors to create a fraction of the input voltage:

Vin
R1
Vout
R2
GND
Vout = Vin × (R2 / (R1 + R2))

Example: With R1 = 10kΩ and R2 = 10kΩ, the output voltage will be exactly half of the input voltage.

Common Examples

1kΩ ±5%
10 × 102 Ω
47Ω ±1%
47 × 100 Ω
68Ω ±1% (50ppm/°C)
68 × 100 Ω
error:

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