120 ohm resistor?

[dmorey]

I am starting to put the LYNX Express together and on step 1 it says that the 120 Ohm resistor is brown red brown black but in the pic it seems to be blue with brown blk blk red brown.What color is it supposed to be?

[batdive]

Its the mainly "blue resistor"  The common coloring is brown/red/brown.  The blue one is a little different but it is a 120 Ohm just colored out a little different.

Future reference I have found this chart very handy in my builds (as some dont tell you the colors)


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In regards to the "Blue resistor" you would go by the bands and here is a chart that breaks it down for you:

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Brown =1, red =2, black =0, 4th band is the multiplier black =1 (120x1=120 ohm) the last brown band is the tolerance in this case:  1%.

Hope this helps.

[bisquit476]

The tan colored resistors are carbon film, the blue one's are metal film. What the difference is, I don't know, but the blue one is (in the Express) the terminator.

[Freebird]

I find that I never trust the color..  Always use an Ohm meter and verify the resistance.

Freebird

[rm357]

That's where the tolerance comes in
1% on 120 ohms would be anywhere between 118.8 and 121.8
5% (gold band) would be anywhere from 114 to 126

The ohm meter is the safest bet, assuming that it is rated and calibrated better than the tolerance of the resistor you are measuring... If the ohm meter is a cheapie that is not calibrated, its a rough measurement at best. I would trust the marking on a 1% resistor more than the reading on an inexpensive ohm meter.

Having said that, in most cases 5% is not going to make that much difference and that is why most of the resistors are tan with a gold band. The 120 ohm is used to termnate the DMX "transmission line" - which is one of those cases where a tighter tolerance does make a difference.

RM
RM

[dmorey]

Thanks!