Series circuits question

Discussion in 'General Electronics Chat' started by jdr188101, Jan 17, 2016.

  1. jdr188101

    Thread Starter New Member

    Jan 17, 2016
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    I have a question regarding series circuits with 3 resistors. I have this circuit, and I do my normal testing for voltage, current, and resistance. Each one of the resistors is a 3kiloOhm resistor. Voltage is 12 v system. Schematic wise, I would have resistor 1 on the bottom leg, resistor 2 on the leg adjacent to the voltage source, and resistor 3 on the upper leg (adjacent from resistor 1). If resistor 2 voltage is halved, what would be the cause of this? Would it be resistor 1 open, resistor 1 short, resistor 2 short, or resistor 3 open? I have been wrecking my brain to try and understand this. If anyone could explain it to me, it would be very appreciative.
     
  2. Veracohr

    Well-Known Member

    Jan 3, 2011
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    I don't understand your description, post a schematic.
     
  3. WBahn

    Moderator

    Mar 31, 2012
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    You description of your schematic makes no sense. Are you aware that "adjacent" means "next to" and not "across from"?

    Please provide a schematic? Just use boxes with labels in Paint if nothing else.

    If they are all in series, then what would the effect be of a resistor going open? Of a resistor being shorted?
     
  4. jdr188101

    Thread Starter New Member

    Jan 17, 2016
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    Its not a great picture by any means
     
  5. WBahn

    Moderator

    Mar 31, 2012
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    It's perfectly workable for this purpose.

    As I suspected, your use of the term "adjacent" is incorrect and, thus, confusing. R1 and R3 are the resistors adjacent to the voltage source and R2 is across from it.

    Now, what voltage do you expect to see across R2?

    What would you expect that voltage to change to for each of the options you gave?

    Do any of them result in the voltage across R2 being cut in half?
     
  6. jdr188101

    Thread Starter New Member

    Jan 17, 2016
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    4 volts across each resistor. And for this exercise, R1 and R3 now have 5 volts.
     
  7. WBahn

    Moderator

    Mar 31, 2012
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    I agree with 4 V across each resistor before whatever happens happens. But after it happens you only know that the voltage across R2 is 2 V, you have no basis for assuming that R1 and R3 equally share the remaining 10 V.

    Take each option in turn and analyze the circuit that results if that condition is what happens.
     
  8. hp1729

    Well-Known Member

    Nov 23, 2015
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    So what would happen under each condition?
    If in doubt build the circuit and try it.
     
  9. dl324

    Distinguished Member

    Mar 30, 2015
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    Are you certain that the resistors are all 3K? Measure their resistance (out of circuit) to see.
     
  10. dl324

    Distinguished Member

    Mar 30, 2015
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    Did you read post #6?
     
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