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few days ago i bought few (about 500) resistors and i noticed that they have 5 color bands instead of 4. My question is how do i count them (which color is the tollerence) and how should i put them? Do they have a good or bad orientation like + or - ? I tried to use an online calculator but i dont know the first and the last band.

enter image description here

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3 Answers 3

up vote 5 down vote accepted

There are only two possible ways to read the resistor's color rings right to left or left to right. One of the two outer rings is the tolerance ring, the other rings indicate value. As others have stated, there is often a subtle difference in (location of) the tolerance ring, but not always too clear. https://en.wikipedia.org/wiki/Electronic_color_code#Resistor_color-coding For cheap and easy to find resistors, the tolerance ring is often gold (5%, 4 band, E12) or red (2%, 5 band, E96)

If you have no clue about value nor tolerance you can decode both possibilities and then check them against the E96 preferred numbers. The one that matches E96 is the correct value. http://logwell.com/tech/components/resistor_values.html

Of course you may want to verify the found value with your multimeter.

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Normally the band that's over the end cap is the right-hand one, but that top row looks pretty ambiguous. The bottom ones are 220 ohms 1%, the top ones look like 220K 1%.

Measure them with an ohmmeter then check with what it should be- there's only two combinations, and not many values have brown as the left band (the most common -1%- tolerance band for 5-band through-hole resistors).

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is there any problem with the orientation of the resistor? –  Meletis Flevarakis Jul 6 at 0:25
    
I think they're both oriented correctly in the photo. –  Spehro Pefhany Jul 6 at 0:43
1  
Resistors don't have a polarity; you can install them however you like. –  alex.forencich Jul 6 at 1:46
    
@alex.forencich It does look messy when they're all inserted will-nilly as to orientation. –  Spehro Pefhany Jul 6 at 2:05
    
True. Just do the same thing with the 1% tolerance band as you do with the gold band on 5% resistors, then. The only annoyance is figuring out which band is the tolerance band on anything that is 1xxx ohms. See the E96 series here en.wikipedia.org/wiki/Preferred_number to clear up any ambiguities. –  alex.forencich Jul 6 at 2:20

In general the tolerance band is separated from the rest of the bands by a very slightly larger gap. It can be hard to tell sometimes.

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