The magneto ignition system works by generating a voltage spike through the generation of a magnetic field inside its construction. The magneto ignition system is constructed in a U-shaped armature. Magnets go around this armature, which creates a magnetic field that generates a small current. As the current builds up, an electric switch inside the control unit begins to open, and inside the switch are two coils that amplify electricity.
The magnetic field inside the armature of the magneto ignition system continues to generate electrical current until the electric circuit reaches its limit. Upon reaching the limit, the electrical switch breaks the ongoing current in the armature and sends it down a primary coil, generating a spike in voltage of around 200 volts. A secondary coil in the system rotates 100 times more than the first one, which further amplifies the voltage upward to 20,000 volts. It is this large voltage that is then fed to the spark plug to turn on the machine.
A magneto ignition system is found in small electric or gasoline-powered devices, such as lawn mowers or chain saws. These devices are too small to require a battery. The Cessna 152 is also started through usage of a magneto ignition system.