Large Jacob's ladder.

Large Jacob's Ladder. This Jacob's Ladder transformer stands about 3 feet tall. A 100 turn coil is used for the primary, and a 23,000 turn coil is used for the secondary. When 120 V.A.C. power is applied to the primary, the secondary coil produces about 25,000 volts. A voltage this large is capable of ionizing the air between the V-shaped electrodes mounted on top of the apparatus. The electric forces are strongest where the electrodes are closest together, at the base of the V. Thus, a spark jumps from the base of one electrode to the other, creating an arc of heated ionized glowing gases that travels upward. When the glowing arc drifts off the top of the electrodes, the circuit is broken, and the arc renews itself at the base of the electrodes. The cycle repeats. NOTE: A tuning lever at the base of the apparatus can be used to achieve the optimum arc. A glass cylinder is used to surround the electrodes to keep the wind currents in the room from extinguishing the arc.