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Thread: Ok Smarty Pants ...... See if yas can answer these :D

  1. #1
    Complete & Utter Member j.m@talk's Avatar
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    Ok Smarty Pants ...... See if yas can answer these :D

    Dropping resistor calc

    Voltage Supply = 12
    Current required = 0.17a
    Resistor value = 56 Ohm
    Forward voltage = ??????

    Voltage Supply = 12
    Current required = 0.17a
    Resistor value = 68 Ohm
    Forward voltage = ??????

    I'm wayyyyy to dim to do these


  2. #2
    Senior Member Shoreguy's Avatar
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    AC single phase, 3-phase or DC?
    Cable length, type and size???
    ...no bridgekeeper will launch me into the abyss I tells ya!!!
    [SIGPIC][/SIGPIC]

  3. #3
    Complete & Utter Member j.m@talk's Avatar
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    Woo DC sorry

    Cable umm 0.5 mm Sq bout 150 mm long
    Last edited by j.m@talk; 03-19-2007 at 10:10 AM.


  4. #4
    Senior Member Shoreguy's Avatar
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    [SIGPIC][/SIGPIC]

  5. #5
    Senior Member Shoreguy's Avatar
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    e=I/R
    3.0
    2.5
    [SIGPIC][/SIGPIC]

  6. #6
    Complete & Utter Member j.m@talk's Avatar
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    Umm .......... Bit low that ......... Looks like I'm gonna have to buy some ............ I'll go on the net & use a handy tool to specify what I want

    Cheers anywho


  7. #7
    Member SJG437's Avatar
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    Good ole Ohm's law :-)

    E=I*R, I=E/R, R=E/I where:

    E = "Eloctromotive Force", "Voltage", "Differential Pressure."
    I = "Amperage", "Amps", "Current."
    R = "Resistance", "Ohms", "Opposition to flow."

    There is also the "Power Formula" - the difference being that Ohm's Law (A resistance formula) can not contain "P" = "Power", "Watts", "Wattage." And the "Power Formula" (A power formula) can not contain "R" = "Resistance", "Ohms", "Oppostion to flow."

    Power Formula

    P=I*E, I=P/E, E=P/I where:

    P= "Watts", "Wattage", "Power."

    Cheers.

  8. #8
    Complete & Utter Member j.m@talk's Avatar
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    Well thats just plain odd .........

    I gotta ATX psu out to test this ......... linked the green to a black to fire up the unit & connected one end of the resistor to a yellow & ran it back through a multimeter .......... 12.2v....... Ehh ? ....... Took the resistor outta circuit 12.2v WTF ? ....... Clicked over to ohms ..... (2000) 56ohm Ummmmmmm ........ Gotta 510 Ohm resistor out ....... 12.2v ......... Connected a LED to it ...... It lit up fine didn't just burn out. ....... Me finks my meter is having issues

    Mind you it read 238vac ok off the mains supply ....... Freakin' wiered


  9. #9
    Guest leprechaun_40's Avatar
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    The answer it lbbowing in the wind of my rectum

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