This animation shows the operation of a transformer, designed to step voltages up or down for more efficient & safer transfer of energy. The primary & secondary wires are wrapped around a solid iron core. Changing current in the primary coil induces a changing magnetic field in the core; this in turn induces the secondary current.

Choose the number of primary & secondary coils by selecting the appropriate number.

Note the voltage & current in each wire.

1. What happens to the secondary voltage if both of the coils have the same number of turns?
2. What happens to the secondary voltage when there less turns of the secondary coil?
3. What happens to the secondary current when there less turns of the secondary coil?
4. What combination of turns produces the highest voltage?
5. What combination of turns produces the brightest light?