What does the primary coil of a magneto consist of?

The primary coil of a magneto typically consists of few windings of heavier wire. This design is significant because the primary coil is responsible for building up a magnetic field when electric current flows through it. Using fewer windings with heavier wire allows the coil to carry a higher amount of current, which is necessary for generating the magnetic field needed for ignition in small engines.

The primary coil functions by rapidly building and collapsing the magnetic field, which induces a high voltage in the secondary winding. This process, known as electromagnetic induction, requires the primary coil to handle substantial current without excessive heating or resistance, which is why the heavier wire is favored in its construction.

The other options suggest configurations that would not meet the performance requirements of a primary coil in a magneto system. For example, many windings of thin wire would increase resistance and reduce current capacity, while a single winding or one made of light wire would not be able to produce the necessary magnetic field strength effectively. Hence, the choice of few windings of heavier wire is integral to the functionality of the magneto.