Tuesday, March 8, 2016

How to read resistor color codes

Resistor is one of pasive component in electronics industry. Resistor used to reduce current flow or lower voltage levels. But, before you can use a resistor you have to know about resistor capacity. There are 1/4 watt, 1/2 watt, 1 watt and 5 watt resistor or more package. For 5 watt and above you can read the resistor spesification by read information written there. But for below 5 watt you must read the spesification using color codes.

Resistor color codes first used in Radio Manufacturers Association (now part of Electronic Industries Alliance[1] (EIA)), and was published as EIA-RS-279. There are two varians of color codes, 4 band codes and five band codes
The colors told us how to read resistor resistance which declared as ohm. In 4 colors resistor you can read it as; 1st band, 2nd band, multiplier and tolerance. Like the image below

And here is value of colour charts of the resistors

For example, as the first image of resistor consist of 4 colors; Red, Violet, Green and Gold. So you can read it as 2 7 x 100K + 5% Ohm = 2700K Ohm or 2M7 Ohm, with 5% tolerance. For the 5 bands, you must read the three first band as number, number four as multiplier and the last (there is longer gap between the last band and previous ones so you will not read it in wrong way) 

Altough resistor has their color codes, it just used at a static resistor, because there are dynamics/ flexible resistor used in electronics industry, such as trimpot, variable resistor, light dependent resistor and many more.

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