电阻色环计算器
指导
电阻色环计算器
Quickly decode resistor color bands to find resistance values, or enter a resistance value to find the correct color band combination. This calculator supports both 4-band and 5-band resistors and displays an interactive visual diagram with real-time results.
如何使用
Select whether you have a 4-band or 5-band resistor from the dropdown. Then choose the color for each band using the select menus. The calculator instantly displays the resistance value, tolerance percentage, and acceptable value range. You can also use the reverse lookup feature by entering a resistance value (e.g., 4.7k, 100, 2.2M) to automatically set the correct color bands.
特征
- 4-Band and 5-Band Support – Decode both standard and precision resistors with automatic band count switching
- Visual SVG Diagram – See an accurate color-coded resistor diagram that updates in real time as you select bands
- 反向查找 – Enter any resistance value in ohms, kilohms, or megohms to find the matching color band combination
- Tolerance and Range – View the exact tolerance percentage and the minimum-maximum resistance range for your resistor
- 即时计算 – All results update automatically with no button clicks required
常问问题
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What do the color bands on a resistor mean?
Each color band on a resistor represents a digit, multiplier, or tolerance value according to an international standard. The first two or three bands indicate significant digits, the next band is a multiplier (power of ten), and the last band shows the tolerance percentage.
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What is the difference between a 4-band and 5-band resistor?
A 4-band resistor has two significant digit bands, one multiplier band, and one tolerance band. A 5-band resistor adds a third significant digit band for higher precision, making it more accurate for applications that require tighter resistance values.
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What does tolerance mean on a resistor?
Tolerance indicates how much the actual resistance can vary from the stated value. For example, a 1kΩ resistor with ±5% tolerance can have an actual resistance between 950Ω and 1050Ω. Lower tolerance (tighter precision) resistors are more expensive but necessary for sensitive circuits.
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Why are standard resistor values not round numbers?
Standard resistor values follow the E-series (E12, E24, E96) which are based on geometric progressions. This ensures that the tolerance ranges of adjacent values slightly overlap, so any resistance value within a range can be covered by at least one standard resistor.
