4 Band Resistor Colour Code Calculator

Resistor Value Formula:

\[ R = (band1 \times 10 + band2) \times 10^{band3} \]

First Band (1st Digit):

Second Band (2nd Digit):

Third Band (Multiplier):

Fourth Band (Tolerance):

Resistance Value (Ω):

Tolerance:

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1. What is a 4-Band Resistor Color Code Calculator?

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

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

2. How Does the Calculator Work?

The calculator uses the standard resistor color code formula:

\[ R = (band1 \times 10 + band2) \times 10^{band3} \]

Where:

\( R \) — Resistance value in ohms (Ω)
\( band1 \) — First significant digit (1st band color)
\( band2 \) — Second significant digit (2nd band color)
\( band3 \) — Multiplier/exponent (3rd band color)
4th band indicates tolerance (percentage variation)

Explanation: The first two bands represent digits, the third is the power-of-ten multiplier, and the fourth indicates tolerance.

3. Importance of Resistor Color Codes

Details: Color coding allows for easy identification of resistor values when printed numbers would be too small to read. Proper identification is crucial for circuit design and repair.

4. Using the Calculator

Tips: Select the colors of each band from the dropdown menus. The calculator will display the resistance value and tolerance.

5. Frequently Asked Questions (FAQ)

Q1: What if my resistor has 5 or 6 bands?
A: This calculator is for 4-band resistors only. 5-band resistors have three significant digits, and 6-band resistors add a temperature coefficient band.

Q2: Why are some multiplier values negative?
A: Gold (×0.1) and silver (×0.01) represent fractional multipliers (10^-1 and 10^-2 respectively).

Q3: What does tolerance mean?
A: Tolerance indicates how much the actual resistance may vary from the marked value. A 100Ω resistor with ±5% tolerance could be between 95Ω and 105Ω.

Q4: Which way do I read the bands?
A: The tolerance band (typically gold or silver) is usually on the right. Some resistors have the bands closer to one end to indicate direction.

Q5: What's the most common tolerance?
A: Gold (±5%) is most common in general electronics, while precision circuits often use brown (±1%) or better.