Abstract: A power device including a magneto and a rectification circuit for rectifying an output of the magneto is provided which is capable of adjusting an output of the magneto without any specific control circuit. A field adjusting excitation coil is arranged on a side of a stator of the magneto so as to generate a field adjusting magnetic flux when it is excited, resulting in a magnet field of the magneto being varied by means of the magnetic flux. The field adjusting excitation coil is connected to an intermediate portion of a current flow circuit for a load current, to thereby be excited by the load current, so that a magnet field of a rotor of the magneto is varied depending on the load current, leading to adjustment of an output of the magneto.

Abstract: A safety device for controlling an ignition circuit for an internal combustion engine associated with a transmission coupling the engine to a load comprises a thyristor adapted to permit, upon conduction thereof, the ignition circuit to produce a high voltage to fire a spark plug provided in the engine, a position-responsive switch adapted to permit application of a trigger signal from a power supply to the gate of the thyristor only when the transmission is in neutral, and a capacitor coupled across the gate and cathode of the thyristor to be charged by a voltage drop thereacross and to provide a trigger signal to the gate of the thyristor. Once the capacitor is charged it maintains a condition wherein the thyristor is turned on whenever the thyristor is positively biased even after the transmission is in gear.