A 2.2k resistor is rated at '1/2 W'. What is the highest voltage you could apply to the resistor without damage to it from overheating?

Would appreciate any help! Thank you

Update:

Hi thank you for the answers, just to clarify, the resistor is 2.2 ohms, not 2.2 thousand ohms. The answer given is also 33V. I tried the equation you provided morningfox but I came up with v = sqrt1.1 

Any more help would be greatly appreciated, I'm struggling on this one

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  • 1 month ago
    Favourite answer

    watts= volts * amps

    Volts = ohms * amps

    So watts = volts^2 / ohms

    In this problem, you have 0.5 W = V^2 / 2200.

    =============

    The original question clearly had 2.2k.  "k" means kilo, as in thousand. Changing the question like you did is called "bait and switch", and is generally regarded as unfair. It's not a "clarification", it is a change to a different question. What next? Are you going to give another "clarification" ... it wasn't 1/2 W, it was 1/2 kilowatt?

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    • M.
      Lv 7
      3 weeks agoReport

      @Ray:  K when used with resistances, means kilo.  Kilo means thousand.  2.2kΩ means 2.2 kilohms which means 2200 ohms.

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  • Anonymous
    3 weeks ago

    With R = 2.2k ohms, E = 33 v 

    With R = 2.2 ohms, E = 1.05 v 

    Approximately

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  • 1 month ago

    watts= volts * amps

    Volts = ohms * amps

    So watts = volts^2 / ohms

    In this problem, you have 0.5 W = V^2 / 2200.   hh

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  • Robert
    Lv 4
    1 month ago

    Most half watt resistors have voltage ratings of 350V . There are a few that will take 500 to 600 volts. There is also high voltage metal film types that can operate with 2.5kV.

    Source(s): Farnell, Rapid Electronics, Digikey.
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  • 1 month ago

    Let me work backwards from the answer, assuming R is unknown.

    P = E^2/R

    0.5 = 33^2/R

    R = 33^2/0.5 = 1089*2 = 2178, which is approximately 2.2k

    If the problem says 2.2 ohms, there's probably a typo, and it's supposed to be 2.2k ohms.

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  • 1 month ago

    p=E^2/R  >>.5=E^2/2.2 >>2.2*.5=1.1=E^2

    sqrt(1.1)=1.05 V  I=1.05/2.2=.477A

    check .477*1.05=.5W

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  • Anonymous
    1 month ago

    Use Watts = V^2/R

    0.5 = V^2/2200

    V^2 = 2200 x 0.5

    V^2 = 1100

    V = sqr Root of [1100]

    V = 33.16V

    V = 33V

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  • Anonymous
    1 month ago

    E=IR so you could use a shortcut and just cut the "R" in half (because of the 0.5W) and that would be 1100 volts

    • Morningfox
      Lv 7
      1 month agoReport

      1100 volts would result in a current of 0.5 amps. Power would be 550 watts, not 0.5 W. The resister would blow up, or melt very fast.

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