1. What is a Resistor Colour Code Calculator?

Definition: This calculator determines the resistance value of a resistor based on its color bands.

Purpose: It helps electronics engineers, technicians, and hobbyists quickly identify resistor values without memorizing the color code chart.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( R \) — Resistance value (ohms)
• \( band1 \) — First significant digit (first color band)
• \( band2 \) — Second significant digit (second color band)
• \( band3 \) — Multiplier/exponent (third color band)

Explanation: The first two bands represent digits, the third band is the multiplier (power of ten).

3. Importance of Resistor Color Codes

Details: Color coding is a universal system for identifying resistor values, especially important for small components where printing numbers would be difficult.

4. Using the Calculator

Tips: Select the colors of each band from the dropdown menus. The calculator will display the resistance value in ohms (Ω).

5. Frequently Asked Questions (FAQ)

Q1: What if my resistor has 4 or 5 bands?
A: This calculator handles 3-band resistors. For 4-band resistors, the first three bands work the same way (two digits + multiplier), and the fourth band indicates tolerance.

Q2: What do gold and silver mean in the multiplier band?
A: Gold represents ×0.1 (10^-1) and silver represents ×0.01 (10^-2).

Q3: How accurate are resistor color codes?
A: The color code gives the nominal value. Actual resistance may vary based on the tolerance band (not shown in this 3-band calculator).

Q4: What's the difference between 3-band and 4-band resistors?
A: 3-band resistors typically have ±20% tolerance, while 4-band resistors have an additional band indicating tighter tolerance (usually ±5% or ±10%).

Q5: Can I use this for surface mount resistors?
A: No, SMD resistors use a different numbering system. This calculator is only for through-hole resistors with color bands.