130. Transformers

A demonstration transformer steps the 110 V AC line voltage up to 10,000 V for a Jacob's Ladder. The current arcs across the shortest distance between two upright conductors. Once started the arc rises, owing to the heated air, and jumps over a distance of several inches.

A secondary of few turns can be substituted to make a stepdown transformer. The low voltage - high current can be used to spot weld sheet metal or to melt a tin ring.