An analog electrical device that allows you to adjust your voltage or current higher or lower, using the principles of induction. They are the big boxes that ominously hum at substations for power plants.

  1. Take a torus of metal, such as iron.
  2. Wind a wire around one side of the torus for n1 turns.
  3. Wind a different wire around the other side of the torus for n2 turns.
  4. Apply some current to the first wire. i amps * n1 turns * C constant = B Teslas induced in the torus.
  5. The torus acts as a circuit for the magnetic field, so the same B Teslas are induced in the other coil.
  6. B teslas / ( n2 turns * C constant ) = i2 amps induced in the second coil.
  7. So: i2/i = n1/n2.
  8. Since power must be conserved, Vout/Vin = n2/n1.

There's usually a significant power loss involved in using transformers, as you need to make two energy transformations. They can also be quite noisy, as the wire loops can pick up magnetic transients from the surrounding environment. And since they rely on having a chunk of metal as a magnetic conductor, anything that requires a non-trivial amount of power is going to weigh a lot more. Transformers are why your stereo and amplifiers are so heavy. Truly, there is more than meets the eye when it comes to Transformers.