simple series ckt

Discussion in 'General Electronics Chat' started by myckts23, Feb 27, 2011.

  1. myckts23

    Thread Starter New Member

    Feb 27, 2011
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    0
    working on simple series ckt with child and am a little stumed -
    thanks in advance

    Voltage source - 3- 1.5V batteries 2A
    2 loads - 1- is light bulb 1- is small motor - do not know ratings (sorry)

    when in parallel both work fine
    when in series - regardless of order - light will not light - motor spins fine.
     
  2. hgmjr

    Moderator

    Jan 28, 2005
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    214
    Can you sketch, scan, and post your circuit here?

    hgmjr
     
  3. myckts23

    Thread Starter New Member

    Feb 27, 2011
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    here it is.
     
  4. hgmjr

    Moderator

    Jan 28, 2005
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    I suspect that if you hold the motor shaft in the series circuit the light will light.

    The parallel circuit allows the optimum voltage and current (power) to be delivered to the load. Another way to state this is that the power (voltage time current) is most efficiently delivered to the load. That is because the output resistance associated with each of the battery individually is combined in parallel in the parallel circuit but this same resistance is in series in the series circuit.

    With the series circuit. the power needed by the motor and light is split up. The power needed to power the motor is less than the power needed to light the light. Thus the motor spins bu tthe light does not light.


    hgmjr
     
  5. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    In the series connection where the light does not come on, try restraining the motor spindle with your fingers - carefully, don't let a little child do this in case he hurts himself. What happens???

    OOps, beaten to it!

    Edit: The motor should draw more current if it is required to deliver more torque (turning effort). When it runs with no load, it only requires as much current as is needed to supply its internal losses.
     
    Last edited: Feb 27, 2011
  6. myckts23

    Thread Starter New Member

    Feb 27, 2011
    5
    0
    thanks - all
     
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