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Where Can I Buy a 100w Resistor?

Discussion in 'General Electronics Discussion' started by Ed Gallop, Mar 13, 2016.

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  1. Ed Gallop

    Ed Gallop

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    Mar 13, 2016
    I have an 18v drill charger die and determined it has a bad 100w resistor. It is China made so rather than buy another charger to burn up another resistor I searched for a better insulated resistor. I can't find one. Can someone here point me in the right direction?
     
  2. Alec_t

    Alec_t

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    Jul 7, 2015
    That's a helluva wattage! How many Ohms? What are the charger and battery specs?
    Plenty of 100W resistors on sale, such as these.
     
  3. Ed Gallop

    Ed Gallop

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    Mar 13, 2016
    There is no information on the charger and I am not very knowledgeable. It has two resistors and I was told to use a 100w by a friend that died last December. The 4 band markings show 2k ohms @ 10% on one and 1k ohms @ 5% on the other. Thanks for the source link. I have an old unused 18v charger and I may just switch the housing to fit the batteries. I am 75 and have not been into electronics in about 50 years.
     
  4. davenn

    davenn Moderator

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    Sep 5, 2009
    I seriously doubt that it is a 100W resistor
    I doubt that physical size of such a beast would fit into the avg charger casing

    10W maybe


    Dave
     
  5. davenn

    davenn Moderator

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    Sep 5, 2009
    OK ... then I suspect you have been mislead

    take some photos of the inside of the charger and of the resistor
     
  6. hevans1944

    hevans1944 Hop - AC8NS

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    Jun 21, 2012
    So, would that be red-black-red-silver bands for one resistor and brown-black-red-gold bands for the other resistor? Most 100 watt resistors I have seen don't have color codes. They just stamp the value on the body because there is plenty of room to do that. And to dissipate 100 watts in the 2 kΩ resistor would require almost 450 V... not too likely to find that in an 18 V drill charger!

    As @davenn said: post some pictures. BTW, I am almost 72 and have been in electronics for more than 50 years. Good luck on re-entering electronics! There have been a few changes.

    And welcome to Electronics Point!
     
    davenn likes this.
  7. Ed Gallop

    Ed Gallop

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    Mar 13, 2016
    Thanks to all for your helpful input. I believe the 4 band markings show 2k ohms @ 10% on one and 1k ohms @ 5% on the other and obviously not 100w. I was incorrectly told to replace it with 100w.
    resistors.jpg
     
  8. BobK

    BobK

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    The bands look like brown-black-red, which is 1K and brown-black-orange, which is 10K.

    They are 1/2 W at most.

    Bob
     
    hevans1944 likes this.
  9. hevans1944

    hevans1944 Hop - AC8NS

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    Jun 21, 2012
    And they appear to be physically in perfectly good condition.
     
  10. Alec_t

    Alec_t

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    Jul 7, 2015
    I doubt that bit of circuitry is much to do with actually charging the battery. It looks more like just an indicator-LED driver. With only 18V as the supply, there's no way a 1k or 10k resistor should pop.
     
    hevans1944 likes this.
  11. donkey

    donkey

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    Feb 26, 2011
    so may I enquire what is the fault of the charger? charging too high? not charging? light not glowing?
    any chance you could send us a pic of the entire innards of the charger, front and back?
    how did you determine the resistor was faulty?
    what tools are you using to measure this?

    I am sorry to ask these questions but we could possibly save this for you depending on what we are looking at
     
  12. Ed Gallop

    Ed Gallop

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    Mar 13, 2016
    Don't be sorry.That is getting to the point.
     
  13. Ed Gallop

    Ed Gallop

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    Mar 13, 2016
    I started the post and had to leave suddenly. Anyway... There is a transformer that plugs into the wall. The output is 20v DC, 400 ma. I just checked and it is supplying 2.0v to the pictured charger section. My best friend said it had a 20v output but he was dying of cancer (passed on 6 weeks later). He must have been confused and saw 20v when it read 2.0v. He said the resistor was bad and I needed to replace the cheap China resistor with a 100w resistor. Electronics was his specialty. I kept him off dying with distractions like this, and he was sharp to the end, so I was convinced it was in the charger section (battery section). I should have double checked. Sorry for all the confusion I caused in this post.
     
  14. donkey

    donkey

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    Feb 26, 2011
    so what size battery you charging? the 2.0v would charge an AA battery at best. if you give us pics, then we might be able to help more.
    the 2.0v to that circuit will just be used to light the LED, so now we need to see the rest of the circuit.
     
  15. Ed Gallop

    Ed Gallop

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    Mar 13, 2016
    The charger is for an 18v drill battery. The charger transformer (plugs in wall) should provide 20v Dc but the output reads 2.0, so the sealed transformer unit is bad. My friend read it wrong. I assumed it was in the wiring after the transformer (charger housing picture provided) and thought the voltage was not going through to the battery. Bad assumption. I should have checked the output myself and did before my last post. I am purchasing a new transformer to solve the problem. You folks here were very helpful and I do appreciate you taking your time to help me.
     
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