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AA mechanic fixes Land Rover with a spud

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    #2
    _Brian
    Registered Users Posts: 18,562 ✭✭✭✭_Brian


    Anyone willing to throw out some detail on the science behind this fix ??


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    #3
    seamus
    Registered Users Posts: 68,317 ✭✭✭✭seamus


    _Brian wrote: »
    Anyone willing to throw out some detail on the science behind this fix ??
    The condenser absorbs the voltage spike as the points open and close when the key is turned, amplifying the spark that eventually starts the engine.

    The potato worked because it was connected to the switching side of the coil, and absorbed some of the energy from the voltage spike, producing a reasonable spark that was able to start the engine.
    A potato is full of electrolytes which easily allows a strong current to pass through it. In fact, you can actually make a battery out of a potato.

    But because the potato would have some internal resistance, running a current through it will increase the voltage at one of the terminals. Sparks can only be produced with higher voltages.

    Voltage = Current x Resistance

    So by increasing the resistance on the circuit using the potato, you increase the voltage, creating a spark.

    His original fix using tinfoil was probably inadequate because the resistance of the tinfoil was very low, thus the voltage produced was very low.


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