It’s easiest to learn four band resistors first. Once you learn the four band system, it is very easy to understand five and six band resistor color codes. The Four Band 100k Ohm Resistor Peek inside the guts of a few carbon-film resistors. Resistance values from top to bottom: 27Ω, 330Ω and a 3.3MΩ. Inside the resistor, a carbon film is wrapped around an insulator. More wraps means a higher resistance. Pretty neat!

As SI units go, larger or smaller values of ohms can be matched with a prefix like kilo-, mega-, or giga-, to make large values easier to read. It's very common to see resistors in the kilohm (kΩ) and megaohm (MΩ) range (much less common to see miliohm (mΩ) resistors). For example, a 4,700Ω resistor is equivalent to a 4.7kΩ resistor, and a 5,600,000Ω resistor can be written as 5,600kΩ or (more commonly as) 5.6MΩ. Schematic symbol It is very easy to read 5 or 6 band resistors if you already know how to use four band resistor color coding. 5 Band 100K Resistor Color CodeIt was a hell of a job to find the right values to reach a wide range of values, fairly equaly spread. In a five-band resistor, the first three bands represent the first three significant digits. The fourth band represents the multiplier. The fifth band represents the tolerance. In this case, the last two bands (i.e. the fifth and sixth bands) should be closely spaced, with a gap between the fourth and fifth bands. To calculate the resistance value, you need to group the values of the significant digits bands — i.e., the values of the first two or three bands from the left, depending on the total number of bands. Then you need to multiply that value by the multiplier to get the resistance value of the resistor.

In a five band resistor, the first four bands tell us the nominal value of the resistor, and the fifth band identifies the tolerance. Six band resistors also have a band that identifies the temperature coefficient (i.e. how sensitive the resistor is to temperature changes). In a typical four-band resistor, the first and second bands represent significant figures. For this example, refer to the figure above with a green, red, blue, and gold band. Using the table provided below, the green band represents the number 5, and the red band is 2.The electrical resistance of a resistor is measured in ohms. The symbol for an ohm is the greek capital-omega: Ω. The (somewhat roundabout) definition of 1Ω is the resistance between two points where 1 volt (1V) of applied potential energy will push 1 ampere (1A) of current. They are read exactly the same way as five band resistors, except that the (additional) last band tells us the temperature coefficient. Color In a six-band resistor, the first five bands have the same representation as a five-band resistor followed by one extra sixth band that represents the temperature coefficient of resistance (TCR). Tolerance Five band resistors have a third significant digit band between the first two bands and the multiplier band. Five band resistors also have a wider range of tolerances available. Since it is a four-band resistor, the first two bands (violet and green) will indicate the significant digits which are, according to the table above; 75.