standard resistor value table
American Electronics Industry Association defines a standard resistor value system (in fact, capacitors and inductors system here is applicable), the system is defined in the last century, at that time were still carbon film resistor technology, the precision is very low. To understand the resistance system, take 10% precision resistors, if the first resistance is 100Ohm, 105Ohm do not need to, because the resistance of 100Ohm precision is 90 to 110Ohm, so the second sense resistor value is 120Ohm, 110Ohm resistance ranging from precision to 130Ohm. Analogy in this way from 100Ohm to 1000Ohm resistor value is 100, 120, 150, 180, 220, 270, 330, etc., which is defined in EIA E12 series resistor values. Some may ask why not, as 100, 120, 140, 160, 180, 200, so? In fact resistance value is counted in accordance with the following formula out, n that the first n-value, N the definition of the class that EIA (N = 192, 96, 48, 24, 12, 6, 3). If you ask why I use this formula? Look at this formula to know more profound, than I can answer.
EIA defines the precision of a few series resistance value, namely E3 E6 E12 E24 E48 E96 E192, E behind the figures represent the total from 100 to 1000 a number of resistance, other resistance index by 10 multiplication and division are, as 4.7Ohm, 4.7KOhm so. The accuracy of all the series definition and values as follows:
E3 50% accuracy (no longer in use)
E6 20% accuracy
E12 10% accuracy
E24 5% accuracy
E48 2% accuracy
E96 1% accuracy
E192 0.5%, 0.25%, 0.1% accuracy, and more
You can see from the table, we choose resistance, it should try to use the compatible family of low precision, such as E6, E12, etc., so you can easily purchase, cheap, delivery time shorter. Compatible with low accuracy he does not spend 10% or 20% accuracy, you can choose to use 1% 5% accuracy, but the best from the E6, E12 and other family and some resistance to the election. If you do not want to find so much trouble in the table, you can click rescal.htm line calculation, simply enter the desired resistance value and precision to which series will automatically calculate your value to the standard resistance.
Resistances identified by two digits plus a 10, said a power, such as the 103 express 10kOhm, 472 that 4.7kOhm. This marked the largest chip resistors (such as the 0805 package) at all. Small chip resistors (such as the 0402 package) is too small not because of any marked only measured with a multimeter. Resistance of the old pin-type packaging is color-coded color rings, 3 digits plus a multiplier, coupled with a precision that, as shown below: