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Most common resistors (to keep in stock)

Discussion in 'General Electronics Chat' started by Marks256, Jan 19, 2008.

  1. Marks256

    Marks256 New Member

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    What are the most commonly used resistors? I am going to restock (actually just stock) my geek-room...

    I am going to get quite a few 100:eek:hm:, 10k:eek:hm:, and 470:eek:hm:.

    Any other ones i just load up on?

    If i need a really odd one, i usually just desolder it from some random board, so i am just ordering the ones that will be used most.

    thanks. ;)

    EDIT: 1/4 watts AND 1/2 watts (if you think i will need any...)
     
  2. dknguyen

    dknguyen Well-Known Member

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    It seems that

    values of 1 to 10 and 2.2, 3.3, and 4.7
    in magnitudes of 10^1, 10^2, 10^3 and 10^4
    are popular.

    Maybe less of the ones below 47 ohms (or 470 ohms?) and beyond 50kohms.
     
  3. Marks256

    Marks256 New Member

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    I am ordering from jameco, so the orders are a minimum of 100 resistors per value.
     
  4. dave

    Dave New Member

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  5. RODALCO

    RODALCO Well-Known Member

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    I stick mostly to the E 12 series.

    Most values i use are > 100 ohms and < 470 k. ohms ¼ and ½ Watt.

    I take odd sizes from old VCR and TV junk boards and remove them with the heatgun.
     
  6. weegee

    weegee New Member

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    I was foruntate that i won an ebay auction for a box of 5000 of each value from the E48 series + several additional values from the E96 range and a box of 0 ohm links (looks like a resistor with a single black stripe) what are these for, the only practical reason i can think of is making pcb jump wires look better.

    I believe they were from a company that went bust, so cost £16 + £8 postage. :D
     
  7. RODALCO

    RODALCO Well-Known Member

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    Yeh. i have seen those 0 ohm links with the black stripe.

    They are probably easier to solder in because the wire ends are of the same material as normal resistors, so pre tinning is not required for automatic soldering, and a machine can insert those.

    Good bargain you got there :D
     
  8. rubiks.cuber

    rubiks.cuber New Member

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    After twenty five years of projects and repairs, there are some that are more common than others.
    More common at top of list:
    10KΩ
    1KΩ
    100Ω
    100kΩ
    1MegΩ


    That has covered me well. Need a 2.2k? Use two 1k's in series. 20% tolerance means that that 2.2k can be as high as 2.6k and low as 1.8 k. However, they are usually better than that anyway, thus a couple of 1kΩ's in series is usually absolutely fine.
    Need 50 K? Parallel two 100k's?
    (3) 10kΩ's in parallel give you the 3.3k, and so on.

    This method works great for repairs and experimenting. Now if you do alot of amplifier projects or higher power applications, more caution is needed on the low end. EXAMPLE: While (2) 100Ω's in parallel could work for a 47Ω, it might not be close enough since typically the lower resistance values are higher wattage(1/2 watt and up). So while two 1/4 watt 100Ω's in parallel might work, and technically be 1/2 watt of dissipation, the difference in the resistance of each resistor is exagerated, and one will be carrying more than half of the current, and this seems to fail alot in power-supply repairs when a 47Ω was required (though its actually not that common a value).

    With the basics above, you can get any resistance you need. If you, however, are a purist, and so not like that mixing method, I would seriously add the following values based on my experience, which agrees with the mathmatical post above:

    2.2 and 3.3 and 4.7 times all values of 100, 1000, and 10,000 (ok, 50k on that one)
    470Ω,4.7k,220Ω, 2.2k, 22k,330Ω, 3.3k,


    Potentimeters? 1k, 20k, 50k are most common. the 20k usually works for either 20k or 10k. 1MegΩ needed once in a while, but not worth stocking alot of.

    Buy 100Ω's in higher wattage, and all the others in the cheap wattages.

    Thats my two cents.
     
  9. kchriste

    kchriste New Member Forum Supporter

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  10. Marks256

    Marks256 New Member

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    I decided to stay away from grab bags... i learned my lesson when i bought a grab bag of ceramic capacitors. They were all crap and unusable to me.
     
  11. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    In a previous thread you were going to order a resistor selection from an Ebay store. What happened ?

    Where they any resistors in the parts cabinet you purchased. Or did you not win that auction ?

    I favor buying a selection. As a last resort you can buy an assortment from Radio Shack. They now have an 1/8 watt assortment for $13. WIth 500 resistors it comes to a bit over 2 cents a resistor. Not too bad.

    They have smaller assortments with fewer resistors of each value for $6.

    While they are not a great buy it beats the heck out of searching for a used resistor on a junked board.
     
  12. weegee

    weegee New Member

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    ebay can be a great source, almost all my passives have come from there. there was a company on ebay selling surplus stock. They said that a lot of electronics factories ditch ALL there surplus stock between each project to ensure that parts dont get mixed up, or parts of the wrong specification get used. Its was the same place i got my resistors from (as above) but i have also had boxes (big boxes 2' square) of capacitors, inductors, diodes, pcb hardware, wires, ect all from this place at under £20 a box. And its all top quality gear, still either in boxes or on spools. Only downside is that you dont know what your gonna get till the box arrives, but i've never been let down. Mabey you can find (via ebay or otherwise) who deals with the surplus stock from the electronics factories near you.
     
  13. Hero999

    Hero999 Banned

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    Get the E6 values (10 22 33 47 68 82) from 10R to 1M and extra E3 values (10 22 47) from 1R to 10M. Low value resistors har handy for current sense resistors and high values are useful for biasing FETs, CMOS crystal oscillators and long RC constants.
     
  14. Andy1845c

    Andy1845c Active Member

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  15. Marks256

    Marks256 New Member

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    Since i am getting free shipping out of jameco, i figure it would cost just as much in the long run. Yes, there were resistors in that cabinet, and i did win, but it didn't say what values it included. I mostly just bought that for the cabinet, with the hope that i will be able to use some of the stuff in it... ;)



    Ok. I will get a kit/assortment from jameco. It is $13 for 540 resistors. That is just over 2c a resistor. I am also going to get 100 of the values 10 100 1k and 10k.

    http://www.electro-tech-online.com/custompdfs/2008/01/P79.pdf

    (top right. the refill for the cabinet. p/n 103166)
     
  16. Dean Huster

    Dean Huster Well-Known Member

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    For years and years, my resistor and capacitor stock came from desoldering old radios, TVs and other circuit boards. As the material got newer, I ended up with new parts, such as transistors, diodes, ICs and smaller electrolytic caps. These sufficed for most of my building. I'd stick with that and really work on tearing stuff apart for parts, especially if you're pinching the pennies.

    Then, as you need a particular part (project "A" requires 3 510 ohm resistors), rather than ordering 3 resistors, order a bag of 100 or 200. As you do this, your stock will begin to build. In fact, whenever I'd order, I'd always check my stock, see where I was short on new parts and order a few values in a quantity of 100 or 200. It's amazing how quickly your stock will build up with new components and the cost is spread out so far that it's painless. Need a single 4013 CMOS IC for a project? Order 5.

    I have NEVER ordered hardware such as screws, washers, nuts, etc. I have several carefully sorted cabinets full of hardware, sorted to the point that if you ask me for a 1-1/2 inch, 8-32 pan head screw, I can find it for you in under five seconds and then start asking you if you want it in plated steel, brass or nylon and then ask if you need Phillips, Torx, standard, hex, Pozidriv ..... my hardware is truly sorted down to that extent -- really anal. I keep large containers on or near the bench. Electronic parts are tossed into one, hardware into another. About every six months or year, I dump a container out on a large bench, sort and store the parts. I have never resorted to a "junk drawer" for parts.

    Desoldering has become more difficult with larger computer boards, so on those, I inventory the ICs, enter them into a computer database with the board number and location that I assign and store the entire board in an out-of-the-way place. Most of the ICs will not be used (I may already have 50 new ones in stock) so there's no point in spending all the time desoldering a used IC with shorter pins that I may never use. The system is similar to todays JIT (just in time) maufacturing. I don't desolder an odd IC until I actually need it.

    Dean
     
    Last edited: Jan 20, 2008
  17. Marks256

    Marks256 New Member

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    My desoldering iron died a few days ago. I am starting to loose my sanity.... It will be a while before i can get to the shack and get a new one... :(
     
  18. weegee

    weegee New Member

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    i like your idea of indexing the boards that have interesting bits, so that you can get them IF you need them.

    are there any good free or cheap software for storing details of what parts you have, that can also store (or link to) the manufacturers data sheet, (a list of alternatives)ect.

    although im reasonably organised - i would love something like this. i wouldnt mind filling it from scratch, in fact id prefer it, that way i know that its right.
     
  19. Marks256

    Marks256 New Member

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    openoffice.org calc.... it is a free open source spreadsheet program
     
  20. Brian218

    Brian218 New Member

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    I'm in the process of making an Excell spreadsheet of everything in my parts bin. It can be sorted, has datasheet links, cost (if applicable) etc. It's a lot of work, since I started from scratch, but it works very well so far. It should eventually eliminate spending hours searching for an obscure part I may or may not have in the junk box.
     
  21. Marks256

    Marks256 New Member

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    But isn't the searching half the fun?
     

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