Electronics: Reading Resistor and Capacitor Codes
Electronics can sometimes be difficult to decipher. By decoding the colorful stripes sported by many resistors and the alphanumeric markings that appear on certain types of capacitors, you can determine the nominal value and tolerance of the specific component.
Resistor color codes
Many resistor casings contain color bands that represent the nominal resistance value and tolerance of the resistor. You translate the color and position of each band into digits, multipliers, and percentages.
The table that follows outlines the meaning of the resistor color bands.
|Color||1st Digit||2nd Digit||Multiplier||Tolerance|
Capacitor value reference
In electronic circuits, the value of a capacitor can be determined by a two- or three-digit code that appears on its casing. The following table outlines values for some common capacitors.
|nn (a number from 01 to 99) or nn0||nn picofarads (pF)|
Capacitor tolerance codes
In electronic circuits, the tolerance of capacitors can be determined by a code that appears on the casing. The code is a letter that often follows a three-digit number, for instance, the Z in 130Z. The following table outlines common tolerance values for capacitors. Note that the letters B, C, and D represent tolerances in absolute capacitance values, rather than percentages. These three letters are used on only very small (pF range) capacitors.
|B||± 0.1 pF|
|C||± 0.25 pF|
|D||± 0.5 pF|