A hand-guided power tool is provided with an internal combustion engine that has a cylinder and a piston disposed in the cylinder and delimiting together with the cylinder a combustion chamber. A connecting rod connects the piston and the crankshaft. The piston in operation of the internal combustion engine rotatably drives the crankshaft. An electronic control unit and an ignition device with a spark plug are provided. A support is fixedly connected to the crankshaft and a signal transducer is fixedly connected to the support. The ignition device, utilizing a signal generated by the at least one signal transducer, fires the spark plug at a timing which is predetermined by the electronic control unit. The support has a polygonal conical receptacle and the crankshaft has a corresponding polygonal conical section arranged in the polygonal conical receptacle to fixedly connect the support and the crankshaft to each other.

A linear electro-mechanical system comprising: a stator including at least first and second stator electronic circuits or groups of circuits; a free piston mover movable in a reciprocating motion relative to the stator, the free piston including: a piston surface; a translator configured so that an electromagnetic force may be applied on the free piston mover by one or more of the stator electronic circuits or groups of circuits; and one or more translator electronic circuits, the system further comprising a switching device for each of the first and second stator electronic circuits or groups of circuits such that the current in each of the first and second stator electronic circuits or groups of circuits is independently controllable, and wherein at least one of the translator electronic circuits is configured to receive power from at least one of the independently controlled stator electronic circuits or groups of circuits during at least part of the stroke of the free piston mover.