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