Abstract: A moisture sensitive film having conductive particles dispersed in a hygroscopic polymer is disposed between a pair of electrodes to construct a moisture sensor. The hygroscopic polymer is a modified polyvinyl alcohol which is obtained by saponifying a polymer comprising vinyl ester units and 0.1 to 15 mol % of ethylenically unsaturated carboxylic acid units such that the vinyl ester units are saponified to a degree of at least 30 mol %. The moisture sensor has improved condensing/drying cycle performance and moisture resistance.

Abstract: In a spot welding gun which is made up of a gun main body which is operated for equalization by a driving source, a stationary electrode tip which is immovable relative to the gun main body, and a movable electrode tip which is connected to a pressing source, both electrode tips are pressed to a workpiece with an even force, to thereby perform a high quality spot welding. The driving source is controlled such that the electrode force of the stationary electrode tip, by the driving source, to the workpiece becomes substantially zero. In this manner, there occurs no difference in the electrode forces by both the electrode tips to the workpiece.

Abstract: When a workpiece which is made up by laminating a plurality of plates of different thicknesses is welded by using a spot welding gun having a pair of electrode tips, the electrode force to the workpiece by one of the electrode tips, which is positioned on the side of a thinner plate, is made larger that the electrode force to the workpiece by the other of the electrode tips. The contact pressure on the side of the thinner plate becomes larger with the result that the contact resistance decreases. Therefore, the nugget on the side of the thinner plate becomes smaller than the nugget on the side of the thicker plate.

Abstract: A feedback amplifier includes an input terminal where an input voltage is detected from an input current; an amplifier circuit which amplifies the input voltage to generate an output signal; a first output terminal from which the output signal is outputted; and a feedback circuit. The feedback circuit includes a feedback resistor connected between the input terminal and the first output terminal; and a diode which connected in parallel to the feedback resistor. The output signal is feedback-controlled in response to the product of the input current and the impedance of the feedback circuit.

Abstract: A welding robot has a gun main body, a stationary electrode tip which is immovable relative to the gun main body, and a movable electrode tip which is mounted on the gun main body and is opened and closed by a pressing source. The gun main body is movable by a driving source in a direction in which both the electrode tips lie opposite to each other. In teaching the welding robot by the movement thereof to each weld spot position of a workpiece, the movable electrode tip is moved in a closing direction relative to the gun main body by the pressing source in a state in which the gun main body is kept stationary at a predetermined position relative to the gun support bracket. The stationary electrode tip is moved in the closing direction by a relative movement of the gun main body relative to the movable electrode tip after the movable electrode tip has come into contact with the workpiece. A position at which the stationary electrode tip contacted the workpiece is detected.

Abstract: An infrared detector comprising an infrared detector element for generating an electrical signal, a support for the infrared detector element, and a circuit board for receiving the electrical signal from the infrared detector element. The support is formed integrally with the circuit board. The support comprises a matrix of composite material essentially consisting of one of thermosetting resins and thermoplastic resins having a thermal deformation temperature of at least 100.degree. C. and a tensile elastic modulus of at least 100 kgf/mm.sup.2, and of carbon fibers contained in the range of 10 to 40% by weight and dispersed in the matrix. The circuit board is formed with a through-hole having an inner surface processed so as to be electrically conductive.

Abstract: A data restoring apparatus for saving data into second storage unit and for restoring the saved data back into the first storage unit after an abnormality occurs in a data processing system, whose program updates data comprising first data and second data stored in the first storage unit. The first data includes a plurality of data blocks and the second data specifies the relation between the data blocks. The present invention sets a checkpoint during execution of the program, saves a data block of the first data into the second storage unit when the data block is to be updated by the program, saves the second data into the second storage unit when the checkpoint is set, restores the first data and the second data, both saved in the second storage unit, into the first storage unit, and restarts the program from the checkpoint.

Abstract: An intumescent fire-resistant coating and a fire-resistant material using the same are disclosed, the coating essentially including (A) at least one inorganic compound selected from the group consisting of a carbide, boride, nitride, carbonitride, or carboboride of titanium, zirconium, vanadium, niobium, tantalum, molybdenum, tungsten, silicon or chromium and a carbide, nitride or carbonitride of boron, (B) a synthetic resin, and (C) at least one phosphorus and/or sulfur compound capable of forming a Lewis acid on heating.

Abstract: A headphone apparatus includes a speaker unit accommodated in an accommodating member of an open-air type, a microphone disposed at a front side of the speaker unit, a circuit arrangement mounted on a circuit board in the speaker unit including a filter for lowering a level of a high frequency component of a signal picked up by the microphone, and a negative feedback loop for feeding back an output of the filter to the speaker unit to thereby lower the level of a low frequency component of circumference noise output from the speaker unit. This headphone apparatus further includes an equalizer having a frequency characteristic substantially opposite to that of the filter, wherein an input audio signal is added to the negative feedback loop through the equalizer and then output from the speaker unit.

Abstract: 1,4-dihydropyridine derivatives of formula (I): ##STR1## wherein Ar.sup.1 and Ar.sup.2 each represent an unsubstituted or substituted aromatic hydrocarbon or aromatic heterocyclic group; and R.sup.1 represents --CO.sub.2 R.sup.2, --SO.sub.2 R.sup.3, --COR.sup.4, --CON(R.sup.5).sub.2, --CH--or --NO.sub.2 in which R.sup.2 is hydrogen, a straight chain, branched chain or cyclic saturated hydrocarbon group, which may have a substituent or a straight chain, branched chain or cyclic unsaturated hydrocarbon group having 2 to 10 carbon atoms, which may have a substituent, R.sup.3 is an alkyl group having 1 to 4 carbon atoms, R.sup.4 is an alkyl group having 1 to 4 carbon atoms or a phenyl group; and R.sup.5 is an alkyl group having 1 to 4 carbon atoms.

Abstract: An improved positively temperature-dependent organic resistor, which is basically a composite consisting of a matrix phase of a synthetic resin and a dispersed phase of electroconductive particles, can be prepared by compounding a crystalline synthetic resin, carbon black, an organosilane compound having at least one alkoxy or alkoxy-substituted alkoxy group in a molecule and an organic peroxide, shaping the resin composition into the form of a resistor and heating the shaped body in contact with an aqueous medium containing a hydrolysis-condensation catalyst for the organosilane compound. As compared with resistors prepared by conventional methods, the resistor obtained by the inventive method is highly stable in the resistivity even after many times of repeated voltage loading.

Abstract: A feature of the present invention is that an overcurrent protection circuit is constituted so as to have the voltage relationship of V.sub.2 /V.sub.1 <V.sub.3 /V.sub.2, wherein V.sub.1 is a voltage applied to a positive temperature coefficient resistor at a steady current, V.sub.2 is a voltage applied to said positive temperature coefficient resistor at the maximum current, and V.sub.3 is a voltage applied to said positive temperature coefficient at the equilibrium current. The equilibrium current is rendered less than the steady current, so that heat generation of the load is effectively suppressed and the advantage of enhanced safety of the circuit is achieved.

Abstract: A DC resistance welding apparatus includes a pair of welding electrodes for sandwiching workpieces to be welded therebetween and a circuit connected to the welding electrodes for supplying a welding current to said welding electrodes. The circuit includes a plurality of parallel-connected rectifying circuits each having a welding transformer and rectifying circuit. The circuit allows a large welding current to be supplied to workpieces, and makes the DC resistance welding apparatus small in size and light in weight.

Abstract: A wireless receiver has an FM receiver for receiving an infrared radiation modulated by an audio signal. The received infrared radiation is demodulated into the audio signal, which is then supplied through a power amplifier to a loudspeaker unit or a headphone unit. The wireless receiver includes a detector for detecting whether or not the infrared radiation is received. An output signal from the detector is used to turn the power supply of the FM receiver and the power amplifier on or off. The user of the wireless receiver is not required to turn the receiver on and off manually.

Abstract: A DC resistance welding apparatus includes a pair of welding electrodes for sandwiching workpieces to be welded therebetween and a circuit connected to the welding electrodes for supplying a welding current to said welding electrodes. The circuit includes a plurality of parallel-connected rectifying circuits each having a welding transformer and rectifying circuit. The circuit monitors the power signal produced by inverters in the power supply to determine the proper energization time by producing a pulse signal corresponding to the waveform of the power signal. The rise and fall of the pulse signal is then detected and differentiated. The differential signal is used as a basis to control the energization time of the welding gun.

Abstract: A direct-current resistance welding apparatus includes pneumatic actuators for pressurizing welding guns, respectively, to grip respective workpieces, an inverter composed of a plurality of parallel-connected switching device units each comprising a pair of series-connected switching devices, and a plurality of welding transformers connected to the welding guns, respectively, and also connected between the switching device units. A timer circuit applies an energization signal to energize the switching device units. The pneumatic actuators are actuated by a control circuit to pressurize the welding guns and successively energize the switching device units according to s sequence read from a sequence memory circuit.

Abstract: A welding transformer for use in a resistance welding machine has primary and secondary coils. The primary coil includes a plurality of spaced juxtaposed coil units mounted on a base board. Each of the coil units includes a plurality of juxtaposed coil unit elements with insulating members interposed therebetween. Each of the coil unit elements includes a plurality of turns of a conductive member, and a plurality of conductors mounted on the base board and electrically interconnecting the coil unit elements. A pair of cores is combined with the coil units.

Abstract: An optical reception apparatus comprises of a prism made by forming in a member of substantially the frustum of a circular cone made of a transparent material a concave portion of a substantially circular cone or substantially the frustum of circular cone whose diameter is gradually reduced in the direction from a small diameter circular outer side surface to a large diameter circular outer side surface of the frustum of the circular cone, and a light receiving element mounted on the prism at its position along a center line of a circle of the large diameter circular outer side surface and also in the vicinity of the large diameter circular outer side surface.

Abstract: This invention is concerned with a device for reducing the external noise reaching the ear in extremely noisy places such as in the vehicle or construction sites. According to the present invention, the external noise in picked up by a microphone provided in the vicinity of an electro-acoustic transducer element, such as a headphone unit, provided in the vicinity of the wearer's ear, and the noise signal converted in this manner into electrical signals is produced as the acoustic signal by the electro-acoustic transducer element. The transfer characteristics and controlled in such a manner that the produced noise signal prove to be an acoustic signal which is of the same frequency spectrum and opposite in phase with respect to the external noise reaching the wearer's acoustic meatus from outside to reduce the external noise reaching the acoustic meatus.

Abstract: A DC resistance welding apparatus includes a pair of welding electrodes for sandwiching workpieces to be welded therebetween and a circuit connected to the welding electrodes for supplying a welding current to said welding electrodes. The circuit comprises includes a plurality of parallel-connected rectifying circuits each comprising having a welding transformer and rectifying circuit. The circuit allows a large welding current to be supplied to workpieces, and makes the DC resistance welding apparatus small in size and light in weight.