Abstract: The invention relates to a mobile loudspeaker apparatus for playing back sound. Mobile loudspeaker systems are often disadvantageous in that they have a poor sound quality or require equipment for a good sound quality that is not easy to transport. A loudspeaker apparatus which firstly provides a good sound quality and secondly is also easily transportable is desirable. Previously, these two requirements were often mutually exclusive. By way of a bistable membrane, or a membrane that is stable in more than two states, said membrane being coupleable to the loudspeaker apparatus, it is possible to manage the balancing act between good transportability and a good sound quality of the loudspeaker apparatus. The bistable membrane can be changed from a stable operating state into a stable transport state. By way of a slight pressure at both ends of the bistable membrane, the latter can be rolled up and consequently changed into the transport state.

Abstract: A lighting apparatus for securing to differently dimensioned objects, in particular mobile devices, is intended to be provided. For this purpose, a lighting apparatus comprising an illuminant and a holding element is proposed, wherein the illuminant is secured to a first end section of a bistable element and the holding element is secured to a second end section of the bistable element, said second end section being situated opposite the first end section. The bistable element is rolled out in a first stable state, such that the illuminant is at a maximum distance from the holding element. The bistable element is rolled together in a second stable state. The lighting apparatus is clampable to the mobile device by spring force of the bistable element.

Abstract: A lighting apparatus for securing to differently dimensioned objects, in particular mobile devices, is intended to be provided. For this purpose, a lighting apparatus comprising an illuminant and a holding element is proposed, wherein the illuminant is secured to a first end section of a bistable element and the holding element is secured to a second end section of the bistable element, said second end section being situated opposite the first end section. The bistable element is rolled out in a first stable state, such that the illuminant is at a maximum distance from the holding element. The bistable element is rolled together in a second stable state. The lighting apparatus is clampable to the mobile device by spring force of the bistable element.

Abstract: The invention relates to a mobile loudspeaker apparatus for playing back sound. Mobile loudspeaker systems are often disadvantageous in that they have a poor sound quality or require equipment for a good sound quality that is not easy to transport. A loudspeaker apparatus which firstly provides a good sound quality and secondly is also easily transportable is desirable. Previously, these two requirements were often mutually exclusive. By way of a bistable membrane, or a membrane that is stable in more than two states, said membrane being coupleable to the loudspeaker apparatus, it is possible to manage the balancing act between good transportability and a good sound quality of the loudspeaker apparatus. The bistable membrane can be changed from a stable operating state into a stable transport state. By way of a slight pressure at both ends of the bistable membrane, the latter can be rolled up and consequently changed into the transport state.

Abstract: A method is disclosed for efficiently analyzing an AC voltage signal with a transformation which transforms the signal from a representation in the time-domain to a representation in the frequency-domain. This transformation can be a fast Fourier transform, a discrete Fourier transform or a Laplace transform. By selecting a higher sampling frequency which is an integer multiple of the standard sampling frequency, the zero crossings of the AC voltage signal can be determined more accurately, which improves the quality of the frequency analysis.