Resistor color bands

FIGURE 15-11 Standard values indicated by resistor color bands. 

Fixed resistors are used when you need to reduce the current by a certain amount. They are easily identified by their size and shape (see Figure 1.3). Their resistance level is indicated by means of colored bands painted on the resistor. 

If you ever need to replace a resistor, you must replace it with a resistor of the same resistance level. The resistance level can be determined by reading the values of the colored bands. Each colored band stands for a number ... 

Table 1.1 lists the colors and their associated values. Remember to always read the colors from left to right ( left on a resistor is the side that has the three colored bands on it). 

Find the 100 ohm (brown-black-brown) resistor. Note that with inexpensive resistors (the author will resist the temptation to use the word "cheap" or even worse adjectives ), "brown" often looks somewhat like purple or red, especially when viewed with fluorescent light or sunlight. Using the multimeter as an ohmmeter, and calibrating it for "zero ohms," measure the resistance, to make sure that the color code is being read properly. The measured resistance should be 100, plus or minus 10% if the fourth band is silver, which could be anywhere between 90 and 110 ohms. Then find the 330 ohm resistor (orange-orange-brown) and measure its resistance also. Set the multimeter to "OFF."... 

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