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Hardware => Lynx Smart String => Topic started by: urthegman on July 13, 2011,

Title: 120 ohm resistor placement on SSC
Post by: urthegman on July 13, 2011,
I realize I should have asked this BEFORE I had 16 controller boards soldered and I know there are pictures in the Wiki that my eyes SHOULD be able to see but can anyone confirm for me that from the top to bottom of the SSC circuit board (Smart String in left to right readable position on bottom left hand corner) that the stripe order on the 120 ohm resistor should be as follows? Or if the position matters?
                                                                                     brown
                                                                                     navy(dark green?lol)
                                                                                     navy(dark green?)
                                                                                     orange(red?)
                                                                                     brown
Thanks very much for any help you can give, George
Title: Re: 120 ohm resistor placement on SSC
Post by: rrowan on July 13, 2011,
Resistors are not directional

They can be soldered in either way. Just make sure you have the correct resistor (normally I verify with a multi-meter)

Cheers

Rick R.

Title: Re: 120 ohm resistor placement on SSC
Post by: urthegman on July 13, 2011,
Thanks Rick, That's a relief. Hmmm, I have a multimeter, how do I test a resistor? I've been assuming Bill marked all the parts bags correctly.  Cheers, George
Title: Re: 120 ohm resistor placement on SSC
Post by: lineman on July 13, 2011,
I have a multimeter, how do I test a resistor?

Set your meter to ohms, I do this with all resistors this way you know you have the right resistor before soldering
Title: Re: 120 ohm resistor placement on SSC
Post by: mokeefe on July 13, 2011,
It's actually Brown-Red-Black-Black-Brown. It's tough to interpret the colors on the blue bodied resistors. This is a 1% tolerance resistor so it has 5 bands instead of the usual 4 on 5% and 10% resistors.  If you're curious on the color coding scheme used, just google "resistor color codes".

Your multimeter should have a setting on the dial for "Ohms" (may just show the Greek Omega letter) or resistance.  Sometimes you have to move the probe to a different hole in the meter too.  Once it is set just put a probe on each end of the resistor and read the value.  BTW, you need to do this BEFORE it is soldered into the board otherwise the reading will not necessarily be accurate.

-Mike
Title: Re: 120 ohm resistor placement on SSC
Post by: JerryPlak on July 13, 2011,

this is a great tool for the Band Resistor Color Codes, this link is for the 5 Band Resistor Color Codes on this link there
for 4 Band and 6Band

http://samengstrom.com/15924820/en/read/5_Band_Resistor_Color_Codes?history=24614782,15924820
Title: Re: 120 ohm resistor placement on SSC
Post by: mokeefe on July 13, 2011,
The thing I don't really understand is why they used the colors brown and red for the tolerance values in 1% and 2% resistors.  You can end up reading the colors backwards.  In this case you get 120 ohms reading the colors in one direction and 10K ohms reading it the reverse way.  At least with the gold and silver you have a chance.

I know...use a multimeter to be certain.

-Mike
Title: Re: 120 ohm resistor placement on SSC
Post by: Rainlover on July 13, 2011,
The numbers on my DMM are a lot bigger and easier to see than the colors on the resistors

John
Title: Re: 120 ohm resistor placement on SSC
Post by: urthegman on July 13, 2011,
Thanks All, I am learning a lot on my DIY journey, before yesterday I had never soldered. Now I am testing resistors, What's next?
Title: Re: 120 ohm resistor placement on SSC
Post by: taybrynn on July 13, 2011,
Next stop ... programming PIC chips ... good job!
Title: Re: 120 ohm resistor placement on SSC
Post by: urthegman on July 13, 2011,
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It's actually Brown-Red-Black-Black-Brown. It's tough to interpret the colors on the blue bodied resistors. This is a 1% tolerance resistor so it has 5 bands instead of the usual 4 on 5% and 10% resistors.  If you're curious on the color coding scheme used, just google "resistor color codes".

Your multimeter should have a setting on the dial for "Ohms" (may just show the Greek Omega letter) or resistance.  Sometimes you have to move the probe to a different hole in the meter too.  Once it is set just put a probe on each end of the resistor and read the value.  BTW, you need to do this BEFORE it is soldered into the board otherwise the reading will not necessarily be accurate.

-Mike



So does that mean I have them in upside down?
Title: Re: 120 ohm resistor placement on SSC
Post by: urthegman on July 13, 2011,
Rick was right, I tested the resistor and got the same reading when I switched the leads. Thanks again all!
Title: Re: 120 ohm resistor placement on SSC
Post by: mokeefe on July 13, 2011,
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So does that mean I have them in upside down?

No, as Rick pointed out, resistors have no polarity.  They can be installed either way.  What I was referring to was that the color code stripes on these 1% resistors is somewhat ambiguous, as you come up with different calculations for the value depending on which direction you read the stripes and it's difficult to determine which end starts the code.

In the end all is well. The blue bodied resistors shipped in this coop are indeed 120 ohm 1%.

-Mike