Connect with us

Resistor distribution

Discussion in 'Electronic Basics' started by George Herold, Jan 8, 2013.

Scroll to continue with content
  1. Fred Bartoli

    Fred Bartoli Guest

    George Herold a écrit :
    Lots of ways. For ex, after a first meas, which you probably even can
    infer from the previous bulk value(s) in the batch you go near the final
    cut position, then make contacts with a wire/flex/whatever that have to
    withstand limited rotation. Or maybe cover the full angle span with a
    spiraled conductor, or brush contacts, or... or...
     
  2. Fred Bartoli

    Fred Bartoli Guest

    Spehro Pefhany a écrit :
    And that one is supposed to help the customer build confidence...

    http://www.mfrelectronics.com/wel.jpg

    Or that one that is just like the machines are in the living room...

    http://www.mfrelectronics.com/capping.jpg

    A friend of mine that once was in charge at Vishay for solving some
    quality issues on a production line for high value resistors (in India
    IIRC) told some horror stories that just reminds me some of those pics...
     
  3. SoothSayer

    SoothSayer Guest

    Not always.

    Matching and culling mass production runs of resistor bodies is easy.

    They can do (read it) it before coating, terminating and marking, or
    they can make it whole, and read it and mark it afterward.

    I am sure that for testing lot run values, they use a platinum faced
    wiper.
     
  4. Fred Abse

    Fred Abse Guest

    Nah! He melts at a much higher temperature ;-)
     
  5. Phil Allison

    Phil Allison Guest

    "SoothSayer"

    ** What an idiotic remark.




    ..... Phil
     
  6. SoothSayer

    SoothSayer Guest

    Yours? Yes, it was... your retarded crack was absolutely an idiotic
    remark to make.

    You grasp of manufacturing processes rests firmly at nil.
     
  7. That's cool, Thanks! Looks like about one resistor every second or
    two.
    So maybe 3x10^7 per year. (I'm still amazed they can make a profit
    selling them.)

    I wonder how many resistors the average American 'consumes' in a year.

    George H.
     
  8. Fred Bartoli

    Fred Bartoli Guest

    George Herold a écrit :
    And that one...


    I particularly love the "spoon coating" at 3:31
     
  9. Oh, man. All that touching, touching, touching with those henna and
    curry-tainted hands. I think this kind of place only exists because of
    historical 40% duties into India and non-tariff barriers such as
    military procurement... otherwise the East Asians (especially China)
    would put them out of business promptly. Their duty rate now is "only"
    18% or so, according to http://www.cybex.in/.


    Best regards,
    Spehro Pefhany
     
  10. legg

    legg Guest

    And the distie???

    You've got to get them into the store buying basics, before you can
    flog the high-markup crap.

    RL
     
  11. Z*ntronics.. many, many years ago, before Bill Ford went off and
    started Tech-Trek.


    Best regards,
    Spehro Pefhany
     
  12. Greegor

    Greegor Guest

    RESISTORS INDIA

     
  13. Hi Tim, I’ve heard that story so many times. I wonder if it’s just an
    urban legend?
    (Has any one every seen for themselves the fabled ‘hole’ in the
    resistor distribution?)
    Hey I’ve got this old case of carbon comp resistors.
    From a physics Prof. (RIP)
    http://bayimg.com/kAiCFAaEH

    The 4.7Meg drawer had a bunch in there so I measured those.
    (4.7 Meg, 1/2 Watt, 10%)

    About 30 resistors, values ranged from 4.36 to 4.71
    Here’s the data,
    http://bayimg.com/LaiCdAaeh

    No obvious hole at 4.7... but not much data either.

    George H.
     
  14. Guest

    Not an urban legend, but............... The manufacturers used to
    make the best resistors that they could and then sort them. So you
    could end up with a hole in a normal distribution. But as the
    manufacturers got better, they had more 1 % resistors than they had a
    market for them. So some of the 1 % resistors were sold as 5 %
    resistors.

    The same thing applies to semiconductors where one can buy say low
    leakage diodes in different grades. The manufacturer makes the best
    ones it can and then sorts for the higher grades.


    Dan
     
  15. Hmm OK, do you have some personal knowledge? So maybe it was only for
    a few years that there was a hole in the distribution? (My old
    resitor box doesn't have any old 5% ers, Maybe there is no hole in
    the 10% R's?)

    Seems if you had a excess of 1% resistors then you should lower the
    price.

    George H.
     
  16. Guest

    The same applies to microprocessors, and I'm sure memory. As they get
    better at producing the parts the yield of the higher speed/lower
    power parts goes up. Of course the orders are for what they are. The
    two have to match somehow. One can adjust price and specs to get them
    in line over the long run but in the short run one goes into battle
    with the weapons one has.
     
  17. josephkk

    josephkk Guest

    Suddenly, i suspect that this was/is a short term stopgap method to ship
    sufficient quantity of the tighter tolerance units used by various
    manufacturers as they got their processes under better control.

    ?-)
     
  18. But even if the mean is off, they are still in tolerance, right?
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-