jacob's ladder effects in films

Discussion in 'General Electronics Chat' started by redacejr, Jun 7, 2008.

  1. redacejr

    Thread Starter Active Member

    Apr 22, 2008
    85
    0
    according to paschen's law, a voltage as "small" as 380v can produce a continuous spark such as the ones we see in jacobs' ladder or wimshurst machines. is it possible to produce such a voltage from low vdc.... or maybe incorporating sparkplucgs from a car....

    IM NOT WILLING TO TRY THIS OUT AS I AM AWARE OF THE DANGER OF SUCH VOLTAGE AND HOW THIS CAN TRANSFORM TO INCREDIBLE CURRENTS AT A MINIMAL RESISTANCE.:eek:

    im just curious about how such effect are created in sci-fi films in the mad scientist's lab and what voltages do they use


    IM NOT SO STUPID TO TRY THIS OUT!!! :eek:

    Redace
     
  2. Xray

    Well-Known Member

    Nov 21, 2004
    58
    1
    Most small "hobbyists" Jacob's Ladders operate at around 15KV to 30KV from the secondary winding of a Neon Sign Transformer (NST). All NST's are current-limited that prevents the transformer from sourcing more than its rated current (typically 30mA). This is done by the manufacturers installing a "magnetic shunt" within the core of the transformer which causes the core to saturate over a certain value of current. The electric arc heating the ambient air is what causes the arc to rise up the metal rods. The rods are often formed into a V shape which causes the arc to lengthen as it rises until the gap is too wide to sustain it, at which case the arc extingwishes, and a new arc is formed at the smaller gap at the bottom.

    As far as arcing at low voltages, yes, an arc can be formed unter certain circumstances at lower voltage. A welding arc is a good example of a relatively low voltage arc. But I doubt very much that you can create a working, stable Jacob's Ladder at the low voltage levels that you are asking about.
     
    Last edited: Jun 7, 2008
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