In the ever-shifting world of electronics, one thing that hasn’t changed over the years is the resistor color code. It is used to identify resistance value and tolerances for cylindrical resistors with axial leads. The International Electronics Commission formally defines the color code in its IEC 60062 standard. Microhm Electronics'  HPMRY series and PMRY series are popular cylindrical resistors.

The resistor color code is expressed in bands of various colors imposed sequentially across the circumference of the resistor. There are three-band versions, versions with four and five bands, and a less common version with six bands. Although originally devised for carbon resistors almost a century ago, the code is still alive and well and is used for both carbon resistors as well as other types of resistors whose packaging takes the same cylindrical form.


Four-band and five-band code are more poluar than three-band versions nowadays.  Microhm Electronics' HPMRY series and PMRY series are cylindrical resistors with five-band codes. The fourth band of a resistor specified by a four-band resistor code is located to the right of the third band, separated by a space, and it specifies the tolerance of the resistor. Otherwise, it is read the same as a three-band resistor. The five-band resistor code is used to specify resistors built to a tighter tolerance. In this case, it is the first three bands that are digits. Then, the fourth band is the multiplier, and the fifth represents the tolerance.


The first three bands of the example resistor (above) are green, purple, and black. That’s 5, 6, and 0. Concatenated together, that yields 560. The fourth band is red, for a multiplier of 100. That indicates a resistance of 56,000 ohms. The last band is gold. Looking at the legend on the bottom of the picture, the gold band shows a tolerance of +/- 5 percent, indicating that this particular resistor can be relied on to be between 53,200 and 58,800 ohms. We can identify the resistance value and tolerance of HPMRY series and PMRY series in the same ways.