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Resistance Is Futile


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Submitted by: Azazel via Submit a Kludge!

Favorite Comment: Fixer Nom nom says, “Ohm Nohm Nohm!”

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  1. Orzo says:

    I have to wonder, what does this person plan to route that s/he thinks that all these resistors are necessary? It borders on mad science…

  2. A Random Pooka says:

    Girl Genius for the win! This must be one of Agatha’s pet projects

  3. boringTroll says:

    Each resistor is 10 ohms, they are in pairs. a pair of 10 ohm resistors in parallel are equivalent to a single 5 home resistor of double the wattage. If I counted right, there are 25 pairs in series, for a total resistance of 125 ohms, with 50 times the wattage of a single resistor. If those are 2 watt resistors, then that is approximately a 100 watt electric heater when connected to 110 volt power.
    If you have priced power resistors recently, you’ll notice that this sort of kludge is not significantly more expensive than buying a single high power resistor, assuming labor is free. (Hobby labor has a negative cost, because the person doing the hobby would be out spending money, if they weren’t spending two hours soldering together resistors.) Often this sort of kludge is much faster, because the small wattage resistors are easily available, whereas the high power resistors are special order.
    In the context of a heater, this form factor will make better contact with the air, and will transfer the heat more effectively than a single large resistor.
    Nichrome wire is the common way to do it in commercial products, however, it requires different tools, techniques and materials. Also, the tolerance is not as fine.
    This might be a dummy load for testing another piece of electronics. This configuration will have a lower inductance than either wire, or a wire wound resistor.
    Check my math, and my logic. 3 internets to the first person to correct an error in this post.

    • Harry says:

      TROLL! TROLL IN THE DUNGEON!!

      I thought you should know. *faints*

    • mrgoogfan says:

      125 ohms at 4 watts

    • Compulsorry says:

      How rude. One can’t even correct errors – such as ’5 home’, although I happily conceed that’s more of a typo than anything else – in own posts on this site, much less those in other’s. One can just point and laugh.

      I suggest you send those internets to Haiti.

    • metagaijin says:

      Mmmm… exposed wiring and 110 volts… what a delicious combination!

      But seriously, a 100 watt heater? What is this for, a hamster cage?

      Anyway, assuming that this is a heater, what’s wrong with a good old 100 watt light bulb? Are you a vampire?

    • PosterGrampa says:

      I think your math is wrong 50 resistors times 10 ohms is 500 ohms (50 X 10 = 500)

      • dwasifar says:

        No, his math is right, assuming he’s right about how they are connected. He said “25 pairs in series,” each pair being two resistors in parallel. Two 10-ohm resistors in parallel have a total resistance of 5 ohms. String 25 5-ohm pairs in series and you have 5 x 25 = 125 ohms.

      • kg333 says:

        That would be the case if the resistors were in series, but these are in parallel.

      • Stoneshop says:

        Better get new glasses, gramps, because your reading is lacking.

      • PosterGrampa says:

        I don’t know res values but these look like from the top down Purple, Black, Brown, Gold that is if my 21″ LCD screen is giving me the right color display. If so what is the res value now?

        • Stoneshop says:

          With your lack of knowledge about these matters (you could *LOOK UP* the resistor value from the colour code, for fuck’s sake, purple-black-brown is not an E12 range value anyway), and the fact that you haven’t even acknowledged that those resistors aren’t all in series (they’re parallel per two, then in series), you’d better keep your mouth shut.

      • TheDuke says:

        Computing circuits isn’t that simple. Resistors connected in series do add their resistance normally, however when connected in parallel the equation is 1/R(effective)=1/R(1)+1/R(2). Therefore since they are first connected in parallel the resistance of 2 combined is half of the resistance of one. Long story short, his math is right.

    • dannysauer says:

      “home” is not an electrical unit, resistive or otherwise.

      you can send the three Internets to my home address. :)

    • Stoneshop says:

      The bit I disagree with is the resistor value: the third ring is not quite the same colour as the first. To me they look to be brown-black-red, so 1k ohm, resulting in an overall resistance of 12.5k. With that, the possible application goes overboard too, unless it’s meant to operate at 1100V.

    • dono1 says:

      “5 home resistor” should be “5 ohm resistor”.
      (Please deposit internets here: __________)

    • Azazel says:

      Actually, those are no less than forty-eight 100 ohm 2 watt resistors, wired in a massive series-parallel configuration resulting in a total resistance of ~300 ohms at ~8 watts. I needed something in the range of a 250 ohm 10 watt resistor, and this configuration was close enough to fit the bill.
      I had a bag of 2 watt 100 ohm resistors laying about from a previous project that flopped, so rather than wait several hours for the stores to open, and spend $7 I didn’t have, I kludged this together.
      I paired the resistors together in 2, resulting in 24 pairs of ~50 ohm 4watt resistors, which got wired in parallel to create a 4 watt 100 ohm mess. Continue in this fashion to the end result that you see here.
      :D

      • Stoneshop says:

        One correction: as you can load each single resistor at 2 watts, the total maximum load would theoretically be 48*2W = 96W. Derating a bit for the fact that they’re not in free air, I’d put this thingamajig at at about 50W.

      • Stoneshop says:

        Actually, just 12 resistors (2 parallel strings of 6 each in series) would have done the job. That setup would be rated at 24 watts maximum dissipation already, so, even with a restricted airflow, the 8 watts you needed done away with would not result in magic smoke release.

      • slim says:

        Azazel, you have to settle an issue between my blistered fellow fixer @Yosh and myself. How were the leads wound? Is that a hand job or a tool job??

        We gots to know.

    • Martyvz says:

      Actually…..the color code on those are red / black / red / gold. equates to 2k ohm with 5% tolerance. And the purpose of placing same value resistors in parallel isn’t to increase the wattage……it only divides the current (more efficient heat dissipation). Wow! All those years spent getting my BSEE have finally paid off!!!

      • Stoneshop says:

        Well, hand back your BSEE and reclaim your tuition fees, because when you put equal resistors in parallel, the maximum dissipation is now equal to a single resistor’s rating times the number of resistors.

        Of course it applies to resistors of dissimilar values too, but the equation gets more complex as you have to calculate the dissipation (through V^2/R) for each resistor individually.

    • Ron says:

      I dunno, are some of these hooked up in quads or is it jusy my eyes?

      I so then your math would indeed be off.

    • msichal says:

      brown-black-red = 1k ohm, 4 in parallel, 1k ohm/4 =250 ohm , those are like 2W, so every 4 are 250 ohm/8W, there are 12 of them in series, so 250*12 = 3000 ohm/8W

      right? :)

    • william says:

      its hard to tell however they appear to be 300 ohm resistors, assuming they are all in parallel this comes to about 7.5 ohms 80 – 200W close to the value of a 8 ohm speaker,

      however the end twenty 300 ohm resistors appear parallel series ten 300 in parallel 30 ohm and another in series = 60 ohm 20 watt and another lot of this in series again = about 120 ohms 20 watt assuming 2 watt resistors, only the kludger and kami sama knows

    • Yosh says:

      They’re actually 100 ohm resistors. 10 ohms would be brown/black/black. It also looks like they’re in bundles of 4, so that changes the equation just a tad.
      Otherwise, you’re right.

      • Azazel says:

        Bingo!
        Bundles of 4, with 2 in parallel and than the two pairs in series.
        Now if this sits and waits with ‘pending moderation’ on it like my last attempt to say what this is, I will be even more amused.

  4. marc says:

    doesnt stuff drop in resistance when you run it in parallel?

    • K6WMD says:

      Yes it does. RT = 1 / (1/R1 + 1/R2 + 1/R3 etc….) Pretty simple really. If all the resistors are the same value, 2 in parallel would cut the resistance in half, 3 in parallel would cut it into a 3rd, and so on. Very basic

  5. marc says:

    umm dito what boringtroll said haha

  6. bonarez says:

    Ah, the law of Kirchoff. We meet again.

    • Lara says:

      Parallel resistors, we meet again.

      I think they’re actually 30Ī©, but I could be wrong.

    • K6WMD says:

      Bonarez, you mean “Kirchhoff?” hahaha sorry, I could not resist. I am such a jerk! hahaha Actually, I’m impressed somebody out there knows who ol’ Gustav was.

  7. marc says:

    actually i dont belive there in parallel

  8. anodean says:

    St. Vidicon, save us from Murphy.

    (I’d offer internets for understanding this, but it would be wrong.)

  9. slim says:

    As someone who has inhaled his share of magic smoke over the years, the following occurs to me:

    - somebody needed a dummy load quickly and built it from whatever was was on hand.

    - some lab geek with an artistic bent felt inspired after a few beers

    - assuming boringTroll’s math is correct, this is the result of an arrogant engineer at some tech firm asking a lab tech to “just get me a friggin 125 ohm resistor”. The tech, tired of the engineer’s lack of detail and being beaten up for not being able to read the guy’s mind, decides to take a stand.

    - if power is applied anywhere close to the rated wattage of this network, it will soon fail – power resistors need free air to radiate the heat they produce (ever seen an undercooled power resistor de-solder itself?).

    - there’s a box in the bottom of a dusty cabinet in every hardware lab full of these kind of ‘curious treasures’

    I have personally witnessed each of the above in my career.

    In case you’re wondering, magic smoke is the stuff they put into integrated circuits when they are manufactured. It’s the juju that makes ‘em do all the cool stuff. There are different kinds of smoke to match the application (digital smoke, analog smoke, that nasty power smoke, etc). If you do something to let the smoke out, the chip – she no work no more. There’s no puttin’ it back in.

    Slim

    SW Guy can struggle with a bug all day and no one knows. HW Guy frys one resistor and everyone in the lab knows immediately.

    • Kenoscope says:

      Better… Fry a flyback transformer….

      • slim says:

        Sorry, failed to mention ferromagnetic smoke, which can have an olfactory hangtime of several days. Guys coming back the next week knew you blew something up. LOTS of the white stuff as the xformer transitions from flyback to a fryback. Impressive fireworks show – no extra charge.

    • NochDguir says:

      @slim and @boring trolls you sirs can have all my Internets troll can have half for his equations and slim for you i give half of my Internets for reminding me of magic smoke i haven’t laughed that hard in years….. thank you both

    • St0815 says:

      In any case, this is pretty nice soldering. For those not familiar with this stuff: the photograph shows the resistors significantly magnified. So I think it’s probably not the work of an engineer, more likely that of a technician. An engineer would have done it in a way so it’s “good enough” or used a bit of PCB to solder the resistors on. (That would have been the better way too: it’s more mechanically stable.) Someone who has soldered every day for a few years might produce a solution like that, because they can do it within minutes.

    • St. Vicodin says:

      You forgot about the magic smoke in a selenium rectifier. Burn up one of those — now there’s a smell one never forgets!

  10. OnlyTheLonely says:

    Uh, those are 1K ohm 5% tolerance resistors (red-black-brown-gold).

  11. Tom says:

    You might want to look at the resistors again. They appear to be red, black red, with a gold tolerance band. 2K 5%. My resoning is only 3 bands are for the value and the forth is for tolerance. The only tolerance colors are none, silver, and gold.

    • Stoneshop says:

      Err, check out 2%, 1% and 0.5% precision resistors. Okay, those have five bands, but the tolerance ring is not silver or gold.

  12. purekindiiy says:

    The resistors are ganged in parallel but alligned in series.

  13. TexasDan says:

    Unless it hurts zombies in some way, I’m not interested.

  14. Liker says:

    as an electrical engineer, i approve.

    • frollard says:

      Seconded. I built one as a dummy load to turn a computer atx power supply into a bench supply on the cheap…needs a small load or it will cook itself. Mounted on the cooling fan = no magic smoke!

      • Archangel says:

        Then, there’s the people who test power supplies without any load, then wonder why they still can’t get power under load conditions.

  15. Nom nom says:

    Ohm Nohm Nohm!

  16. towny says:

    since i don’t see any line in or line out, i beleive this is an aborted plan A.
    a.k.a a pile of junk

    • boringTroll says:

      You can see a black insulated wire connected at the back. I assume there is another connection, or perhaps two connections. It is possible this is intended to be used like a high power potentiometer, except that an alligator clip is used instead of a slider.

  17. Sarah says:

    I remember finding computer chips with these thing on them and I had fun wabbling them back and forth until the popped off. My Dad was not pleased. Never knew what they were before.
    What are the chicklet looking ones called?

  18. XKCD Fan says:

    Ohm never for his dying Uncle’s words: “With great power comes great current times squared resistance.”

  19. I’m inclined to think this is a piece of art that would sell in Greenwich Village for $43 or in Asheville, NC for around $75. See? It’s a city, and in fact a biting commentary on today’s techno-centric society by a nature-loving hippie!

  20. Sarge says:

    Great, but what the fark is the kludge here? A kludge still has to do something: All I see here is a mess of resisters. No PCB, no power supply, no logic board, no other electrical components period.

    NOT A KLUDGE!

    • Squirrel says:

      So what? you sayin this is an art project?

    • frollard says:

      its either a heater or a dummy load to test something else. I built one similar to do just that – keep a regulator circuit from blowing up.

    • Stoneshop says:

      Oh, it’s you again.

      There *IS* a wire in the back, and there *IS* a wire on the left, so there is the distinct possibility that you can run a current through it. What more do you need, Mister “these kludges aren’t neat enough”?

      Sod off.

    • Rob says:

      But it DOES do something, it allows current to flow with a deliberately measured amount of resistance to current flow.

      If this is (for example) a homemade substitute for a high-power 1200Ī© resistor that would have to be shipped air express from Shenzen, it is, IMHO, every bit as much of a kludge as an anvil placed atop the water hose leading to a sprinkler for slow irrigation.

  21. elite_pete says:

    comments from the geek gallery. probably the smartest pop-culturally visible site out there that isn’t news based, good work team.

    now which one of you nerds is gonna teach me how to wire LEDs to my jacket like i was hasselhoff on the berlin wall?

  22. ck159 says:

    Ohm My God

  23. Chris says:

    Resistor’s are ridiculously cheap, I think I’d just buy the right size resistor and do away with that kludge.

    • Nuclear Larry says:

      But where are you going to find a 360 ohm 10 Watt resistor? Four sets of eleven parallel 1 K resistors, in series, are 363.6 ohms (approximately).

      Plus resistors-R-us will take at least two days to deliver, once the PO request gets through the trolls in Purchasing. Not to mention the zombies in Shipping who delivered the package to the office supply administrator.

      It would be much easier to kludge up this little piece of artwork and actually use some of the 14,000 leftover resistors than fight the great Lord Papyrus and all of his little minions.

  24. smilr says:

    My first thought was of a jury-rigged resistor pack for heater/ac fan speed control.

    On my oldsmobile the speed of the fan is controlled by passing power through one or more of a set of “resistors”. Said resistors consist of a few differing lengths of wire (nichrome?) looped into loose coils and mounted to the inside of the outside air intake for the fan. I never did get around to testing if they were set up as a variable voltage divider or what, but the full load of the fan appeared to be drawn through them when on.

    Immediately I thought of these as a DIY replacement for what is probably a $15 GM part, consisting of $0.50 in materials.

  25. Dogmeat says:

    As is their daily early morning ritual, the resistor monks have gathered in the courtyard to recite their mantra:
    “Ohhhhmmmm ohhhhmmmm ohhhhmmmm…”

  26. slim says:

    What really impresses me about this monstrosity are the neat little coils made by wrapping a lead of resistor A around a lead of resistor B. Nearly impossible to do by hand, it’s like the guy used some mac-daddy wire wrap tool prior to sparking up the solder gun. Extra style points for a little order in an otherwise psychotic assembly.

    • frollard says:

      yay! Someone else noticed!

    • Yosh says:

      Actually, it’s easy to get tightly wound leads like this if you start out with leads that are long enough. I’ve earned more than my fair share of blisters doing this before.

      • slim says:

        I rarely use the words ‘easy’ and ‘blisters’ to describe the same task(unless the task easily causes blisters). That said, I gotta give you props for your effort.

  27. blytherubbings says:

    Clearly wirewrap but a very sloppy job at it.

  28. Torri says:

    Changing the R/C values on a dollar store count down timer? Now instead of a 3 hour limit it lasts about a week?

    Um, never mind, I’m gonna go turn my room into a Faraday cage now.

  29. JB Tait says:

    I am having trouble deciding from the image whether we are seeing red black orange or orange black brown, but that stack (with a couple of boards it could have been cordwood) looks suspiciously like a dummy load for making a computer power supply into a bench supply. I use a Radio Shack power resister and a blue retro automotive lamp these days and get a steam punk effect, but I have built loads that looked like that thing, in the past.

  30. Nilloc says:

    Needed to charge my iPhone after getting trapped in his basement with nothing but a 220 dryer outlet and a box of resistors.

  31. Interesting kludge. I can see that this is 40 1W resistors, a mix of 1K and 3K resistors wired as 20 parallel pairs in series. R = about 20K, P = 40W. Not a shunt for current or power measurement; this load is meant to draw some heavy power. Going to take quite some voltage to drive those resistors to 40W. V = sqrt(PR) = sqrt(800000) = 894V. In danger of having some arcing going on from node to node. May be a ham-radio dummy load for transmission testing, meant to be tucked inside a grounded coffee can, possibly filled with non-conductive liquid coolant. (Motor oil works.) Not for a kilowatt HF base station, though (it would melt); more for a car radio (25W-50W). (I’m an electronics technician and a ham, so I have an eye for such details.)

  32. Baltic says:

    Looks like something from an old (Soviet) DIY electronics book I’ve read – they used similar setup to connect 127 V motor to 220 V outlet without a transformer, since both transformers and high-power resistors were expensive and difficult to find back then.

  33. OtherGuy says:

    It’s actually the limiter circuit for a flux capacitor.

    Straight out of a DeLorean (normally hidden behind the passenger dash, near a convenient heat duct.)

  34. lagrangel5 says:

    Interesting kludge. I can see that this is 40 1W resistors, a mix of 1K and 3K resistors wired as 20 parallel pairs in series. R = about 20K, P = 40W. Not a shunt for current or power measurement; this load is meant to draw some heavy power. Going to take quite some voltage to drive those resistors to 40W. V = sqrt(PR) = sqrt(800000) = 894V. In danger of having some arcing going on from node to node. May be a ham-radio dummy load for transmission testing, meant to be tucked inside a grounded coffee can, possibly filled with non-conductive liquid coolant. (Motor oil works.) Not for a kilowatt HF base station, though (it would melt); more for a car radio (25W-50W). (I’m an electronics technician and a ham, so I have an eye for such details.)

  35. Dr, Techie says:

    Somebody heard that “massively parallel” was the hot thing in computing.

  36. Crudus says:

    This is not what I intended when I said “resistance is futile”.

  37. CookieMonster says:

    Come on guys you’ve got to laugh at this kludge… Resistance (to not to) is futile…

  38. Tron9000 says:

    1Kohm (brown-black-red = 1 – 0 – 10^2)

    50 in parallel = 20 ohms (1000/50) or you can do it long way round of working out using 1/R=1/R1+1/R2+…….1/Rn

    wattage is 150W!!! (3W x50)

    good going BTW! but what the hell are you using it for!

    • lagrangel5 says:

      I was seeing the resistors as being 1W, but it’s hard to tell because there’s no visual reference. I had counted 40 resistors last night, but on closer inspection, it looks like 4 rows of 6 pairs, or 48 total. So if they’re 3W each, total would be 144W. I agree that some of them are 1K 5% (brown black red gold); but some look like 3K 5% to me (orange brown red gold). That might be a trick of the light, though; my fingers itch to put a Fluke on those babies and see what the actual values are.

  39. blkgrrl says:

    Just waiting for . . .O.o Um, ohm, ha-ha! This is a Kludge. A pic with the smoke would’ve been cool!

  40. Ktd says:

    Resistors are useless.

  41. slim says:

    To contribute to this community, I tried to share a handy method to remember the resistor band color code (Bad Boys…) that I learned back in school. That, evidently, had a few too many bad words for this site, and was rejected by the decorum police. Please know that I was trying to help, not to offend.

    It works too – haven’t forgotten the resistor codes in 35 years.

    Sadly, with today’s extensive use of surface mount components, the resistor color code has been relegated exclusively to the domain of power engineers. Soon, like those big heads on the Galapagos Islands, the code’s purpose will be lost forever (demonstrated above by the intent disagreements above as to which number was indicated by the color RED).

  42. Wuzzat? says:

    So to sum up what all of you are saying, you will need 1.21 gigawatts and travel at 88mph to travel back in time?

  43. Joseph says:

    We are Radioshack of Borg – resistance is futile…

  44. Zapp1982 says:

    *wisp* *wisp* *wisp* and carry the 1. —– 1.21 Giggawatts! Success!


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