Abstract: A thermal protection circuit arranged in an integrated circuit for protecting a power delivery is disclosed. The thermal protection circuit for protecting a power delivery circuit includes a first thermal sensing circuit exhibiting a negative temperature coefficient characteristic for sensing a temperature of the power delivery circuit and providing a first voltage, a second thermal sensing circuit exhibiting a positive temperature coefficient characteristic for transforming the temperature of the power delivery circuit to a second voltage, an amplifier electrically connected to the first voltage and the second voltage for providing a control signal, wherein the amplifier is a function of a voltage difference between the first voltage and the second voltage, and a switch electrically connected to an output of the amplifier for limiting a maximum current passing there through in response to the control signal.

Abstract: The present invention provides an apparatus for reducing the allowed output current from an electrical device such as a high output capacity vehicle alternator in response to a sensed over temperature condition. In one embodiment, a thermistor is attached to the housing of an alternator to provide temperature sensing capability. As temperature exceeds a temperature set point established by a resistor bridge, op-amps, in combination with a power FET in series with the alternator field windings, act to reduce the allowed current output from the alternator in proportion to the extent the set point temperature has been exceeded. As the alternator temperature returns to below the set point, the output current restriction is reduced such that the allowed current flow is maximized without exceeding the temperature set point.

Abstract: A surge protection apparatus connected between an electrical power line source and a load includes a voltage input, an inductor, and a protective barrier. The voltage input is coupled to the electrical power line. The inductor is coupled between the voltage input and the load. The protective barrier is interposed between the inductor and the load, and is configured to physically isolate the inductor from the load.

Abstract: The VLSI circuit has one or more integrated semiconductor chips disposed in a housing and connected via connecting lines to contact terminals that are accessible from outside the housing. A temperature sensor chip is in thermal contact with the semiconductor chip in the housing. Connecting lines connect the temperature sensor chip to additional contact terminals of the housing.

Abstract: A synthetic fiber cable, preferably of polyamide material, consists of a bundle of load-bearing synthetic material fibers and at least one conductive temperature sensor element extending a length of the cable. The temperature sensor element forms, in dependence on the temperature, a conductive connection over the length of the cable, which connection is constantly monitored by a measurement circuit. The connection is interrupted at a checking circuit in the case of temperatures critical for the synthetic fiber cable. The temperature sensor element can be a fine wire melting at the critical temperature. The synthetic fiber cable can be used in elevator installations amongst other things as a safety device, especially as a fire alarm.

Abstract: The present invention relates to a polymer fuse apparatus that provides bypass fuse protection. A polymer bypass fuse is comprised of an electrical conductor wherein a portion of the conductor is surrounded by an internal electrode, which is then surrounded by a layer of polymeric positive temperature coefficient (PTC) material, which is then surrounded by a conductive material similar to that of the internal electrode. Various hybrid combinations are also contemplated where in-line and/or bypass fuses are combined with other circuit components. One example is, a plurality of in-line and bypass fuses combined with a differential and common mode filter, which itself consists of a plurality of common ground conductive plates maintaining first and second electrode plates between the various conductive plates, all of which are surrounded by a material having predetermined electrical characteristics to provide fail safe filter and circuit protection.

Abstract: A cap 14a and a resin case 14b accommodate a thermite case 26 and an ignition 29, the thermite case 26 comes into contact with a first buss bar 11a and a second buss bar 19a, and a heating agent 27 is charged into the thermite case 26. A retainer 45 which can be attached to and detached from the resin case 14b mounts a compression spring 39a in its compressed state. When the retainer 45 is mounted to the resin case 14b, the retainer 45 comes into contact with the thermite case 26. If the ignition 29 is ignited by a signal indicative of an abnormal condition sent from outside, the heating agent 27 is heated, the retainer 45 is melted by the heat, the compression spring 39a is stretched and the thermite case 26 jumps up. Therefore, the electrical connection between the thermite case 26 and the first buss bar 11a and the second buss bar 19a is interrupted.

Abstract: A secondary protection device for protecting a circuit. The device includes a first positive temperature coefficient (PTC) resistor, a bidirectional zener diode and a second PTC resistor connected in series across input terminals. Output terminals are connected across the bidirectional zener diode for providing a protected output to the circuit. A second zener diode is coupled between one end of the bidirectional zener diode and a ground potential for limiting an output voltage to the circuit.

Abstract: The present invention provides simple, low cost power control circuits and methods for high frequency (e.g., RF) applications. According to one embodiment of the present invention, a high frequency circuit comprises a capacitor, a PTC element and a resistor. The PTC element is heated by a high frequency input signal and changes its resistance. The change in the resistance of the PTC element controls the output power of the circuit. In another embodiment of the present invention, the circuit comprises a high frequency circuit and a control circuit. The control circuit provides a DC current to the high frequency circuit to control the resistance of the PTC element, which in turn controls the output power of the high frequency circuit. In this embodiment, two separate paths are used: one for high frequency input signals and one for DC control current.

Abstract: An NTC thermistor has an electrically insulating substrate, a temperature-sensitive film on a surface of the substrate containing oxide of rare earth elements such as LaCoO3 as its principal component by at least 50 weight %, and a pair of electrodes which are separated from each other and are each electrically connected to this film. An NTC thermistor chip is obtained by further forming a pair of outer electrodes which are each on a corresponding end portion and electrically connected to a corresponding one of the surface electrodes.

Abstract: A chip burn-in system maintains the temperature of IC-chips near a set point, while the IC-chips undergo large step increases and large step decreases in power dissipation as they are tested. The system includes a hot fluid circuit in which a hot fluid circulates from a reservoir through heat exchangers and back to the reservoir, and in which the heat exchangers exchange heat by conduction between the hot fluid and the IC-chips. To keep the temperature of the fluid in the reservoir nearly constant, the system includes an electric heater which operates with a fast response to add heat to the fluid returning to the reservoir as a function of one control signal; and an analog valve which operates with a slow response to add a cold fluid to the reservoir as a function of another control signal.

Abstract: A method for monitoring the operating temperature within a card shelf having a plurality of discrete electronic cards includes receiving a first temperature indicative of an operating temperature of an item on one of the electronic cards. A second temperature indicative of an ambient temperature in which the electronic card is operating is also received. Based on the first and second temperatures, a temperature controller determines whether the item is operating within specified limits.

Abstract: An electrical protection system on a power distribution side includes a control element of a series combination of a PTC device thermally coupled with a resistive device, and a relay coil coupled with relay contacts. If the relay contacts are open the only way in which they can be closed is by supplying current to the relay coil through a resistance-capacitance network. An electronic control module on a control side includes an electronic control module for monitoring a voltage present in the system, and a switch for opening a current path feeding the system upon detection of a fault condition. An indicator indicates presence of a sensed fault condition.

Abstract: The present invention relates to a polymer fuse apparatus that provides bypass fuse protection. A polymer bypass fuse is comprised of an electrical conductor wherein a portion of the conductor is surrounded by an internal electrode, which is then surrounded by a layer of polymeric positive temperature coefficient (PTC) material, which is then surrounded by a conductive material similar to that of the internal electrode.

Abstract: An electrical circuit protection device has an overcurrent protection portion and an overvoltage protection portion. The overcurrent protection portion has a surface. The overvoltage protection portion is disposed on the surface. In one preferred embodiment, the overcurrent portion includes a PTC device and the overvoltage portion includes a voltage variable material. A number of terminations are configured to connect the overcurrent protection portion and the overvoltage protection portion to a printed circuit board.

Abstract: A circuit is provided for selectively providing electric supply voltage from an input feed line with a neutral conductor, a phase conductor and optionally an earth conductor to individual or parallel-connected groups of connected terminals each comprising a phase core, a neutral core and optionally an earth core, to which electrical units using electricity, for instance light fittings, are or can be connected, which circuit includes: a neutral connection between the neutral conductor and each neutral core; optionally an earth connection between each earth conductor and each earth core; a phase connection between the phase conductor and each phase core, in which phase connection is arranged a current control element; and an overcurrent safety element, for instance a fuse, which is incorporated in each phase connection and which limits the current to the maximum value determined for the relevant phase connection.

Abstract: An integrated circuit including one or more power devices, and circuitry which reliably (and independently) shuts down each power device that is detected to be in an undesired operating condition (e.g., one or both of an overcurrent condition and an overvoltage condition) that causes a thermal fault, but which does not shut down any power device that is not in such undesired operating condition. In typical implementations in which the integrated circuit has multiple power devices and an overvoltage detection circuit for each power device, the integrated circuit includes a thermal fault detection circuit and logic circuitry which receives the output of the thermal fault detection circuit and each overvoltage detection circuit. The logic circuitry generates signals which shut down appropriate ones of the power devices in response to the thermal fault detection and overvoltage detection signals it receives.

Abstract: A protective device against excessive currents occurring in an electric circuit between a voltage source and a load mounted downstream of said device, comprising a first triggering component with high current sensitivity and adapted to be triggered, rapidly, but reversibly, in case of excessive current in the circuit, and a second triggering component, mounted in parallel with the first, capable of bearing a temporary voltage higher than the power supply voltage, when the first component is triggered, and of being triggered rapidly and reversibly thereafter. The triggering component are preferably conductive polymer components. Also, a triac switch comprising such a protective device mounted upstream of the triac and a third component is mounted on the triac trigger.

Abstract: An excess current interrupting structure comprising a conductive wire rod which generates heat by an excess current connected between a pair of electric conductors, a circumference of the conductive wire rod being covered with a resin with a thin coated layer formed in the vicinity of a path of the conductive wire rod.

Abstract: A circuit breaker and method for interrupting the flow of electric current in a line having a load and a source including a first switch connected in series with the line and a first actuating device coupled to the first switch and adapted to be actuated by at least one activating signal, to move the first switch from the closed position to the open position. A resistor having a positive temperature coefficient of resistivity is connected in series with the first switch and a voltage limiting device is connected in parallel with the resistor. A second actuating device is coupled to the first switch and is adapted to be actuated by at least one remote control activating signal, to move the first switch to the open position or to the closed position. The second actuating device further includes a coil and a second switch connected to the coil and to the line, the second switch adapted for activating the coil upon the receipt of the remote control activating signal.

Abstract: An isolation circuit for isolating a load node from a power supply secondary inductor includes a Zener diode and a PTC thermistor. The Zener diode electrically couples the load node to a ground and is capable of being in a substantially conductive state when the voltage between the load node and the ground exceeds a predetermined threshold and is also capable of being in a substantially non-conductive state when the voltage between the load node and the ground does not exceed the predetermined threshold. The Zener diode has a non-conductive temperature corresponding to when the Zener diode is in the substantially non-conductive state and a conductive temperature corresponding to when the Zener diode is in the substantially conductive state. The PTC thermistor electrically couples the power supply secondary inductor to the load.

Abstract: The electric power breaker for breaking the electric power is placed on the midpoint of the electric power line from the battery power supply, and the electric power line is extracted from the electric power breaker. In addition, the electric power supply terminal is placed on the midpoint on the electric power line, from which the electric power is supplied to the individual electric loads. The electric power distribution and the electric power supply operation to the electric loads are controlled by the multiplex communication. A semiconductor device having a self protection function is used as the switching device for supplying the electric power. The electric power line covered by the electric conductive material is arranged in a loop topology so as to start from the connection point to the battery and pass through the designated positions in the vehicle and return to the battery.

Abstract: A generally rectangular, planar electrical overcurrent sensing device having a top major surface and a bottom major surface includes a patterned metal foil conductor defined along the top major surface. The metal foil conductor has a first electrode region at one end region, a second electrode region at an opposite end region, and a current-concentrating region extending between the first electrode portion and the second electrode portion. The device further includes a planar sheet of a composition which exhibits PTC behavior and which comprises an organic polymer having a particulate conductive filler dispersed therewithin. The planar sheet has a first major surface in thermal contact with the bridging portion and has an opposite second major surface.

Abstract: The present invention is an electrical circuit protection device having a PTC element with a first common electrode affixed to a first surface of the PTC element and at least two second electrodes affixed to a second surface of the PTC element. The at least two second electrodes are physically separated from one another such that when the at least two second electrodes are connected to a source of electrical current, the current travels from the at least two second electrodes, respectively, through the PTC element, to the first common electrode.

Abstract: The present invention relates to a polymer fuse apparatus that provides bypass fuse protection. A polymer bypass fuse is comprised of an electrical conductor wherein a portion of the conductor is surrounded by an internal electrode, which is then surrounded by a layer of polymeric positive temperature coefficient (PTC) material, which is then surrounded by a conductive material similar to that of the internal electrode. Various hybrid combinations are also contemplated where in-line and/or bypass fuses are combined with other circuit components. One example is, a plurality of in-line and bypass fuses combined with a differential and common mode filter, which itself consists of a plurality of common ground conductive plates maintaining first and second electrode plates between the various conductive plates, all of which are surrounded by a material having predetermined electrical characteristics to provide fail safe filter and circuit protection.

Abstract: A method for interrupting current is provided wherein substantially all current is conveyed through a normal current carrying path in a circuit interrupter. A movable element is displaced for interruption of the current, and a balance is struck between the normal current carrying path and a parallel alternative or transient current carrying path. The transient current carrying path includes at least one variable or controllable resistance element. The transient current carrying path presents a substantially open circuit during normal operation. The variable resistance elements have a lower resistance during initial phases of circuit interruption, favoring transition of all current from the normal current carrying path to the transient path. Thereafter, the variable resistance elements increase in resistivity, producing additional back-EMF to drive the fault current to a zero level and to limit let-through energy.

Abstract: A circuit for detecting and automatically responding to ground faults. A passive protection PTC resistor is coupled in series with an active protection switch, the active protection switch being controlled by a control circuit to open the switch when excess current is detected to be flowing in the common path of one of the channels. Floating and grounded versions are described.

Abstract: Apparatus and method to identify chafing of a conduit, thereby reducing the failure of any system which would be damaged or whose function would be impaired by abrasion of the conduit. Such a system may carry electrical power, fuel, other fluid, hydraulics, pneumatics, optical, or electromagnetic signals. Wear caused by rubbing against external structures is detected by wrapping the conduit with a sensing element, which may be a conductive wire, waveguide, fiber optic cable, or a tube (wound around the conduit or enclosing it) that holds a fluid under pressure. The sensing element is positioned so that chafing on the conduit electrically contacts, breaks, or punctures the sensing element well before the conduit fails.

Abstract: A layer of thermal fusible material is placed on one surface of a metal oxide varistor (MOV) to monitor the heating of the MOV due to applied voltage spikes. The thermal fusible material is part of the electrical circuit which includes the MOV and melts at a predetermined temperature. In the presence of a severe or a number of voltage spikes the MOV heats up and the heat transferred to the thermal fusible material causes it to open the electrical circuit to the MOV to prevent overheating and thermal runaway. In another form, the MOV is separated into two halves and the thermal fusible material layer is placed between the ends of the MOV halves.

Abstract: A positive thermistor device used in a motor activating circuit device of a refrigerator for example includes a positive thermistor element having a pair of opposed electrodes, each of which receives compressive force elastically applied from a corresponding one of spring contact members to hold the thermistor element at a predefined position in the device. When the thermistor device is destroyed, the element breaks into fragments, some of which remain in contact with the spring contact members. The remaining fragments deviate in position to ensure that they do not conduct electricity, resulting in an open state, wherein any current flow is inhibited through such fragments. More specifically, a positive thermistor disk is held within the device so that it is interposed between conductive spring contact pieces and insulative position-alignment projections, which are cross-diagonally situated with respect to each other.

Abstract: The input resistance of an electrical protective device connected to protect telecommunication transmission lines and associated telecommunication equipment is reduced by connecting a resistor in parallel with the coil of resistance wire of a heat coil. The resistor is a low resistance positive temperature coefficient resistor.

Abstract: A direct-to-digital temperature sensor is formed with a single switched-capacitor integrator, having a digital sequencer control.

Abstract: The present invention provides a two-terminal, transistor-PTC, circuit protection device that has a reduced size and weight and is particularly suitable for use, for example, in portable electronic devices and high density electronic circuits. According to one embodiment of the present invention, a circuit protection device comprises a positive coefficient temperature (PTC) element and a bipolar transistor having base, collector, and emitter terminals. The PTC element is connected between the base and collector terminals of the transistor. The PTC element may be thermally coupled to the transistor and packaged with the transistor as a hybrid device. An electrical load may be connected to the collector terminal of the transistor. According to another embodiment of the present invention, a circuit protection device comprises a PTC element and a Darlington circuit having base, collector and emitter terminals. The PTC element is connected between the base and collector terminals of the Darlington circuit.

Abstract: A circuit protection device for protecting an electrical load includes a three-terminal switch element such as a bipolar, or junction or metal-oxide-semiconductor field effect, transistor and a positive temperature compensation (PTC) resistor. In several embodiments the PTC resistor is in series with the current-carrying electrodes of the transistor. In other embodiments the PTC resistor, or a second PTC resistor, is connected to a control element of the transistor. Both DC and AC load-protection circuits are described.

Abstract: A multi-tap distribution apparatus is encased in an enclosure comprising a boxed shaped housing (2) with one side open and a main body (1) fitted in the opening of the housing. A pair of operating windows (13) are recessed in the main body for mounting and removing thermistors (14). Four connectors (4) are projected into each operating window through insertion holes (13a) in the bottom surface of the window. The connectors are coupled to a current transmission circuit (18) which feeds distribution output terminals (5) with operating currents. Four thermistors can be detachably coupled to the connectors without opening the enclosure. By coupling and detaching each thermistor, operating currents can be passed and blocked to the corresponding distribution output terminal (5). Each operating window (13) is normally closed up with a cover (3) to keep out rain and external noise.

Abstract: An electronic motor protection system which protects electric motors against various fault conditions such as over-temperature (12) of the individual windings of the motor and low voltage (18, 20). The system has a power supply compatible with 24, 120 or 240 VAC input voltage using only two input terminals. According to a first embodiment, line voltage is inputted to a transformer (T1) while the combination of a zener follower (Z1, Z2, Q1) and series regulator (U1, Q2, Q3) provide independent DC voltage supply levels or voltage rails (VR1, VR2) for control circuitry over a wide range of input voltages. A dead-band voltage range is provided by a circuit section (20) which works in conjunction with a 240 volt, low voltage cut-out circuit section (18) to prevent the possibility of chatter in 240V motors and excessive voltage from being applied to 120 volt motors.

Abstract: A high voltage, current limiting device is connected in series with a high voltage power source and a protected load to interrupt current for an over-current condition [Typically 50 kA]. The current limiting device includes a current sensor/isolator and a switch connected in series. A current limiter, which may include a fuse or polymer current limiting material, is connected in parallel to the current sensor/isolator. The current sensor/isolator includes a pair of electrically insulated supports secured to a plurality of support rods to maintain the insulated supports at a predetermined fixed spacing to support an expulsion fuse. The expulsion fuse link includes a pair of copper conductors of adequate current carrying capability that are attached to ends of a main weak link fuse. A pair of coil springs hold the weak link fuse under tension to repel the conductors apart when the weak link fuse melts open during an over-current condition.

Abstract: The present invention relates to a polymer fuse apparatus that provides bypass fuse protection. A polymer bypass fuse is comprised of an electrical conductor wherein a portion of the conductor is surrounded by an internal electrode, which is then surrounded by a layer of polymeric positive temperature coefficient (PTC) material, which is then surrounded by a conductive material similar to that of the internal electrode.Various hybrid combinations are also contemplated where in-line and/or bypass fuses are combined with other circuit components. One example is, a plurality of in-line and bypass fuses combined with a differential and common mode filter, which itself consists of a plurality of common ground conductive plates maintaining first and second electrode plates between the various conductive plates, all of which are surrounded by a material having predetermined electrical characteristics to provide fail safe filter and circuit protection.

Abstract: A power supply with an input protection circuit is disclosed. The protection circuit includes a thermistor that heats up if the power supply is mistakenly connected to an excessive input voltage. When the thermistor gets hot, its resistance increases, and isolates the down stream portion of the power supply from the input voltage. A relay in parallel with the thermistor is closed, thus shorting the thermistor, after a preset time if the input voltage had a proper magnitude.

Abstract: An auxiliary power port such as is found in an automotive vehicle passenger compartment has a receptacle connected with the vehicle electrical system and a tubular, removable sleeve which fits inside the receptacle and receives a standard adapter plug of the type intended for use with automotive power ports. The exterior surface of the sleeve is covered with a layer of positive temperature coefficient (positive temperature coefficient) material, and insertion of the sleeve into the receptacle places the positive temperature coefficient layer in contact with the inner surface of the receptacle. The inner surface of the receptacle, the outer surface of the sleeve, and the positive temperature coefficient layer sandwiched therebetween form a positive temperature coefficient circuit overcurrent protection device. A number of interchangeable sleeves having different hold currents are provided for use with different electrical devices.

Abstract: A molded case circuit breaker and current suppressing unit protects an electric motor without tripping during motor current reversal. The circuit breaker trip unit provides long time, short time and instantaneous over current protection against abnormal overload and low-current short circuit currents within the protected circuit. The current suppressing unit rapidly suppresses high-current short circuit currents until the circuit breaker responds to isolate the protected equipment.

Abstract: A fault current interrupter is provided by the parallel combination of a polymer current limiter and a voltage dependent resistor connected across a pair of separable contacts to permit the interruption of current without the occurrence of arcing between the contacts when the contacts first become separated. The polymer current limiter is selected to have a relatively low resistance at quiescent operating currents and a substantially higher resistance at short circuit overcurrents. This allows the current to transfer away from the contacts through the polymer current limiter until the voltage across the voltage dependent resistor causes the voltage dependent resistor to become conductive and thereby transfer the current away from the polymer current limiter.

Abstract: A communication system (10) includes a central office (16) that provides communication services to a plurality of subscribers (18) using differential transmission line pairs (21). The differential transmission line pairs are vulnerable to lightning strikes that may damage equipment coupled to the differential transmission line pairs. A protection circuit (51A) protects equipment from damage from a lightning strike and allows for continued operation after the lightning strike. The protection circuit involves automatically resettable fuses (66, 81) in parallel with non-resettable fuses (67, 82). Continued operation is effected at a normal level after a weak lightning strike, and at a reduced level after a strong strike.

Abstract: A PTC-element to be used as a protective device against overcurrent or overvoltage, of which the volume resistivity does not substantially differ before and after a high temperature processing, such as reflowing of solder, and can be preserved even after having been subjected to repeated tripping, which contains a non-conductive crystalline polymer and a particulate conductor material dispersed in the non-conducting crystalline polymer, wherein the particulate conductor material includes electro-conductive particles having irregular surface contours.

Abstract: A circuit for driving a plurality of light emitting diodes (LEDs) that includes a power supply and a voltage divide circuit utilizing positive and negative temperature coefficient thermistors to boost the drive voltage to the LEDs as the ambient temperature deviates from room temperature, which compensates for increased electrical resistance of the LEDs at low temperatures and decreased LED light output efficiency at high temperatures. The circuit also provides a signal voltage to indicate the drive current through the LEDs, and includes a transistor to shut down the power supply when the signal voltage drops below a predetermined level (i.e. the number of burned out LEDs exceeds a predetermined number). A compensation circuit utilizes a thermistor to boost the signal voltage as the ambient temperature drops to compensate for the characteristic turn-on voltage of the transistor that increases as the temperature of the transistor drops.

Abstract: An electrical device which includes a resistive element which exhibits PTC behavior, is composed of a conductive polymer composition, has a planar shape with first and second major surfaces, and has a thickness of at most 0.64 mm . The resistive element is sandwiched between first and second metal foil electrodes, at least one of which has a thickness of at least 0.055 mm, so that the ratio of the resistive element thickness to electrode thickness is 1:1 to 16:1. The device can be used as a circuit protection device in an electrical circuit.

Abstract: An overcurrent protection system containing (1) a current sensing means; (2) a first switch coupled to the current sensing means; (3) a voltage sensing means; (4) a PTC device; and (5) a second switch coupled to the voltage sensing means. In one type of system, the second switch is connected in series with a parallel combination of the first switch and the PTC device; and the voltage sensing means is connected in parallel with a series combination of (i) the second switch and (ii) the parallel combination of the first switch and the PTC device. In another type of system, the first switch, the PTC device and the voltage sensing means are connected in parallel with each other; and the second switch (i) is a switch which latches in the open position and (ii) is connected in series with the parallel combination of the first switch, the PTC device and the voltage sensing means.

Abstract: The present invention sets forth a new device comprising a PTC, and a transistor in direct physical contact with the PTC. The PTC has a first surface and a second surface wherein at least one of the surfaces is substantially flat. Preferably, the transistor comprises a MOSFET coupled to and located on a flat surface of one of the first and second surfaces of the PTC. The device further includes insulating material coupled to the PTC, a conductive pad coupled to the insulating material, and a conductor coupled between the conductive pad and a gate junction of the transistor. A similar conductive pad and conductor arrangement is provided for a source junction of the transistor. The MOSFET is coupled at a drain junction thereof to one of the first and second surfaces of the PTC, and the device includes a non-conductive encapsulating material around at least a portion of the transistor and the PTC. The combined PTC/MOSFET device provides switching and overload protection features.

Abstract: A semiconductive ceramic composition having negative resistance-temperature characteristics, wherein the composition comprises lanthanum cobalt oxide as the primary component, and, as secondary components, at least one oxide of an element selected from B, Fe and Al and at least one oxide of an element selected from Si, Zr, Hf, Ta, Sn, Sb, W, Mo, Te, Ce, Nb, Mn, Th and P. A semiconductive ceramic composition having a resistivity of approximately 10 .OMEGA..multidot.cm to 100 .OMEGA..multidot.cm at room temperature is obtained by controlling the amount of additives. Since the resistivity at room temperature can be enhanced to several times or more that of the conventional compositions while characteristics of the conventional compositions are maintained, the composition may be widely applied to control heavy current.

Abstract: A system for controlling electric motors in binary and hybrid applications, particularly motors which are used to control windows which can be moved downwards from one extreme position to another extreme position by a single touch of the switch, and between other positions by depressing the switch so long as movement is desired. In this system, a control element is placed in series with the electric motor. The control element has an interrupt component and a sense component which are coupled in series, and the series combination is coupled in parallel with a control component. When the electric motor reaches one of its extreme positions, the sense component senses an increase in the current drawn by the motor. The sense component then signals the control component to cause the interrupt component to interrupt the current and stop the motor.