Abstract: A three-dimension active silencer includes a measuring unit for detecting a signal relating to a sound radiated from a target sound source which is located in a closed box. A plurality of additional sound sources are arranged around the target sound source. A microphone is arranged at a predetermined position for detecting a sound power at the position. A controller is adapted to control respective amplitudes of the additional sound sources which can be different from an amplitude of the target sound source and respective phases of the additional sound sources, based on the signal detected by the measuring unit, in such a manner that the microphone detects the lowest sound power. The additional sound sources are arranged in such a manner that a position xp of the target sound source, respective relative positions di (i=1, 2, . . .

Abstract: A three-dimension active silencer includes a measuring unit for detecting a signal relating to a sound radiated from a target sound source which is located in a closed box. A plurality of additional sound sources are arranged around the target sound source. A microphone is arranged at a predetermined position for detecting a sound power at the position. A controller is adapted to control respective amplitudes of the additional sound sources which can be different from an amplitude of the target sound source and respective phases of the additional sound sources, based on the signal detected by the measuring unit, in such a manner that the microphone detects the lowest sound power. The additional sound sources are arranged in such a manner that a position xp of the target sound source, respective relative positions di (i=1, 2, . . .

Abstract: Disclosed is a dc-to-dc converter comprising a switching transistor, a pulse-width modulation controller, a sandwich-type planar inductor, which accumulates an electromagnetic energy at ON state and releases the accumulated electromagnetic energy at OFF state of the switching transistor, a smoothing capacitor, a rectifying element, and a planar search coil for detecting an overcurrent flowing the planar coil, disposed on one of the outer surfaces of the soft magnetic layers constituting the planar inductor.

Abstract: Disclosed is a dc-to-dc converter comprising a switching transistor, a pulse-width modulation controller, a sandwich-type planar inductor, which accumulates an electromagnetic energy at ON state and releases the accumulated electromagnetic energy at OFF state of the switching transistor, a smoothing capacitor, a rectifying element, and a planar search coil for detecting an overcurrent flowing the planar coil, disposed on one of the outer surfaces of the soft magnetic layers constituting the planar inductor.

Abstract: In a monitoring system for detecting a quench in a superconductive coil to which AC power is supplied, a switch apparatus is connected between the coil and a A.C. power source. A voltage between a top of the coil and a dividing resistor connected in parallel with the coil is detected and converted into a voltage signal by a insulation amplifier and a current flowing through the coil 1 is detected by a current detector and is converted into a current signal by an amplifier. The voltage signal is detected with the current signal as a reference signal by a phase detector so that a signal component of the voltage signal in phase with the reference signal is outputted from the phase detector. The signal component is averaged in a averaging circuit, when the voltage signal is out-of-phase with the reference signal, an output signal is generated as an alarm signal from the averaging circuit.