Common Resistors

Discussion in 'General Electronics Chat' started by noteleks, Jun 25, 2009.

  1. noteleks

    Thread Starter New Member

    May 10, 2009
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    I am having to buy special resistors for old radios. I have to have a minimum buy. What would be common resistors that are used for different electronic projects? That way I can buy some other resistors that I probably will use later when I expand my hobby to modern electronics. Thank you.
     
  2. bill2009

    Active Member

    Apr 17, 2009
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    what size(wattage) are your radio resistors - do the standard value ones have to be the same? That might make them large for everyday electronics use.

    I note that for $12.49 Radio Shack will give you a 500 piece assortment:
    I bought one of these in the winter and it seems to have everytrhing I've needed since. I haven't needed many of the smaller values.

    Also, I note that 1/8 watt resistors are becoming common.
     
  3. Wendy

    Moderator

    Mar 24, 2008
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    Not for older radios their not. The norm for old electronics is more in the ½W, and 1W, sometimes more. The question is still a good one though, what is the wattage range you are looking for?

    What part of the world are you in?
     
  4. noteleks

    Thread Starter New Member

    May 10, 2009
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    Good question. Yes, I have been to Radio Shack. One resistor that I need is 2 m ohms, Radio Shack only goes up to 1 m ohms. It has to be the 1/2w as Bill states. I am ordering from an online company that does radios. But you have to have a $15.00 min. So I decided that I would also buy resistors that I could use on future electronic projects. Not radio projects though, more up to date stuff. Thank you.
     
  5. tom66

    Senior Member

    May 9, 2009
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    Two 1MΩ resistors in series is equivalent to 2MΩ.
     
  6. Wendy

    Moderator

    Mar 24, 2008
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    Actually, you only need a ¼W for a 2MΩ resistor. I wouldn't want to be close to the voltage that uses half that wattage.

    What resistors have you decided on?

    I've done something similar, and posted it here, but mine was a lot easier because they were all ¼W.

    http://forum.allaboutcircuits.com/showthread.php?t=12341
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
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    Check my math if you want - for 350 volts (figuring on highest imaginable B+) and 2M to ground, you get .175 mills. Using I^2 * R, that is 61 milliwatts (.06125 actual). More that I would have thought, but a long way from 1 watt.
     
    Last edited: Jun 26, 2009
  8. Wendy

    Moderator

    Mar 24, 2008
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    Sigh. :rolleyes: I should have done the math. Still 354V RMS or DC is pretty significant.
     
  9. ifixit

    Distinguished Member

    Nov 20, 2008
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    Also... don't forget to check that the resistors voltage rating is not being exceeded.
     
  10. bertus

    Administrator

    Apr 5, 2008
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