Abstract: A micro-electromechanical system comprises a substrate (S) and at least two micro-elements (1, 2) of which a first is bistably switchable. The micro-elements (1, 2) have faces (3a, 4a) facing one another, which are produced by a structuring method and thereby initially have at least one minimal distance from one another characteristic of the structuring method. The first micro-element (1) is then switched to the other stable state (B) whereby the distance between the faces (3a, 4a) facing one another is smaller than the characteristic minimal distance for the structuring method. The micro-electromechanical system can be constructed as an electrostatically actuatable microswitch with improved switchability. Laterally and horizontally operating micro-electromechanical systems with new functionality and current-free closed relays can be implemented.

Abstract: The invention relates to a novel method of producing a resistor device comprising a PTC-polymer element 2 and a varistor element 4. Both elements are molded in a common molding process using one common mold. Preferred is co-injection molding. The invention further relates to the resistor device thus produced and a current limit means including the resistor device and a switch (FIG. 4).

Abstract: A microswitch produced from a predominantly plate-shaped substrate can include: a stationary contact piece (7, 9) on the substrate, a moveable contact piece (6), which electrical contacts the stationary contact piece (7, 9) in the switch-on position of the switch and is electrically isolated from the stationary contact piece in the switch-off position of the switch, a bendable contact carrier (1) which holds the moveable contact piece (6) and is fixed to the substrate by two ends (2, 3), and a drive (10) which guides the contact carrier (1) into the switch-on or switch-off position by elastic deformation. The contact carrier (1) can deform in substrate-parallel fashion. In a stable position corresponding to the switch-off position, the contact carrier (1) has the form of a symmetrical antinode. In a stable position corresponding to the switch-on position, the contact carrier (1) is deformed in the manner of an asymmetrical antinode.

Abstract: The invention relates to a combination of a microrelay switch (1) switching off small overcurrents, and a short-circuit current limiter, for example a fuse link, a PTC thermistor 16 or a power breaker, for limiting or switching of large overcurrents.

Abstract: The invention relates to an apparatus for limiting an electrical current by using a PTC resistor being monitored by a monitor circuit. According to the invention, the monitor circuit issues a signal only after detecting the status of the PTC resistor for a defined time period after a PTC resistance change.

Abstract: The invention relates to a novel micro relay for switching electric currents, in which a movable contact piece 1 moves parallel to the substrate.

Abstract: A fuse has a fuse element (6), composed of silver, with constrictions (7) which follow one another at regular intervals, and which fuse element makes contact with a combustible element (8), preferably over its entire length. The combustible element (8) is composed of a combustion compound, which is essentially of a fuel such as guanidine or a guanidine derivative and a metal such as Mg or Al and an oxidant such as KNO3, NaNO3, NH4NO3, KClO4, NaClO4, KMnO4, the proportion of which is overstoichiometric by a factor of at least 1.1, and preferably of at least 10. The combustible compound also preferably contains a binding agent such as paraffin, a thermoplastic or an elastomer, so that it can be extruded. It has an ignition temperature of between 160° C. and 260° C. and emits more than 200 J/g of heat, so that it ignites even in the event of small overcurrents and melts the entire length of the fuse element (6).

Abstract: An electrical monitor circuit in which star points of taps on a first and a second side of a three-phase current limiting device are voltage compared. Possible applications are combinations with electrical switches, especially for power supplying and protecting circuits for electrical motors.

Abstract: The nonlinear resistor has varistor behaviour and has a matrix and a filler in powder form which is embedded in the matrix. The filler contains sintered varistor granules with predominantly spherical particles of doped metal oxide. These particles are made up of crystalline grains separated from one another by grain boundaries. The filler also contains electrically conductive particles, which cover at most a part of the surfaces of the spherical particles, and/or the varistor granules contain two fractions of particles with different sizes, of which the particles in the first fraction have larger diameters than the particles in the second fraction and are arranged essentially in the form of close sphere packing and the particles in the second fraction fill the interstices formed by the sphere packing.

Abstract: The invention relates to an electric device with a PTC polymer element having a constriction. The constriction defines a web extending in a main current direction over a length longer than in the prior art, namely longer than 5 mm, preferably longer than 15 mm. Further, the aperture angle of the PTC polymer material at the ends of the web is larger than 100°. A preferred choice of material is given, further. The invention achieves very high voltage-withstand capabilities.

Abstract: A protective element for protecting in particular an electric motor against overload currents includes in a polymer matrix, preferably ETFE, for example 40% (by volume) of a first powdered filler of a conductive material, preferably TiB2, so that, as in the case of a PTC element, the resistance increases abruptly at a switching temperature corresponding to the melting temperature of the polymer. Also added are 20% (by volume) of a second powdered filler, a phase transition material which, at a critical temperature below the switching temperature, undergoes a phase transition in which it absorbs heat of transformation. As a result, the response time (T) of the protective element is notably extended in a range of the overload current factor (F) corresponding to higher permissible motor starting currents.

Abstract: A description is given of a PTC polymer element (1) as part of an electrical component with a novel structure in which aperture angles (&agr;) on both sides of constrictions (2) in the PTC polymer material are at least 100°. As a result, an improved response behavior can be achieved, and, in connection with further features, the construction of PTC polymer elements which are more rapid, capable of carrying greater currents and have higher dielectric strengths is possible.