Transformer

Meet the transformer, SparkVille’s quiet voltage changer. It has two windings on a magnetic core. Alternating current in the primary creates a changing magnetic field, which induces an alternating voltage in the secondary. The separate windings in our example do not touch electrically.

In an ideal transformer, V₂ / V₁ = N₂ / N₁: more secondary turns raise the voltage, fewer lower it. A transformer creates no extra power. Steady DC gives no continuous secondary voltage and can overheat a winding.

Before SparkVille’s evening festival, the windmill has an important delivery: electricity for the lanterns across the square. A transformer lowers the alternating voltage to the level their bulbs need. Energy passes from one winding to the other through the magnetic field, with no wire joining them.