A fast algorithm is used to study the transient behavior due to the step-like pulse. This algorithm consists of two parts: The algorithm I reduces the computational complexity to T.sup.0N.sup.3 for large systems as long as T<N; The algorithm II employs the fast multipole technique and achieves scaling T.sup.0N.sup.3whenever T<N.sup.2 beyond which it becomes T log.sub.2 N for even longer time. Hence it is of order O(1) if T<N.sup.2. Benchmark calculation has been done on graphene nanoribbons with N=10.sup.4 and T=10.sup.8. This new algorithm allows many large scale transient problems to be solved, including magnetic tunneling junctions and ferroelectric tunneling junctions that could not be achieved before.

A method detects an error in a meter having a current transformer, a burden resistor unit and a resistive path switchably connectable across the burden resistor unit. The method includes obtaining in the processing circuit a first value representative of the voltage magnitude across the burden resistor unit while the resistive path is operably decoupled across the burden resistor unit. The method also includes closing a switching element to operably couple the resistive path across the burden resistor unit, and obtaining in a processing circuit a second value representative of a voltage magnitude across the burden resistor unit. The method further includes determining in the processing circuit whether an error exists based on the first value, the second value, and at least one predetermined stored value.

An object of this invention is to obtain a phase voltage detection circuit that can detect a phase voltage signal reliably even when a leak current flows therein and a DC bias voltage of the phase voltage signal varies. A phase voltage detection circuit that detects a phase voltage signal generated by an armature coil of an AC power generator includes a peak hold circuit that determines an envelope of the phase voltage signal using an operational amplifier, a voltage offsetting circuit that shifts an output voltage from the peak hold circuit by a preset offset amount, and a comparator that compares the phase voltage signal with an output voltage from the voltage offsetting circuit, and outputs a phase voltage detection signal.

A peak detector circuit comprises a first output coupled to ground by a first load and to emitter terminals of first and second switching devices. A second output is coupled to ground by a second load and to emitter terminals of third and fourth switching devices. A third output is coupled to a supply voltage node by a third load and to collector terminals of the first and second switching devices. A fourth output is coupled to the supply voltage node by a fourth load and to collector terminals of the third and fourth switching devices. The first, second, third, and fourth switching devices have control terminals which are biased with a common bias voltage. The first, second, third and fourth load are selected so that R1=R2=αf*R3=αf*R4, with R1, R2, R3, R4 being a resistance of the first, second, third and fourth loads, respectively, and αf a common-base current gain of the switching devices.

A peak detector circuit comprises a first output coupled to ground by a first load and to emitter terminals of first and second switching devices. A second output is coupled to ground by a second load and to emitter terminals of third and fourth switching devices. A third output is coupled to a supply voltage node by a third load and to collector terminals of the first and second switching devices. A fourth output is coupled to the supply voltage node by a fourth load and to collector terminals of the third and fourth switching devices. The first, second, third, and fourth switching devices have control terminals which are biased with a common bias voltage. The first, second, third and fourth load are selected so that R1=R2=αf*R3=αf*R4, with R1, R2, R3, R4 being a resistance of the first, second, third and fourth loads, respectively, and αf a common-base current gain of the switching devices.

The present disclosure provides a method for detecting an electrical discharge in an electrical apparatus. The method includes sensing an electromagnetic wave using an electrical sensor and generating an electric signal for a predetermined time period, sensing an acoustic wave using an acoustic sensor and generating an acoustic signal for the predetermined time period. The acoustic sensor is associated with at least one compartment of the electrical apparatus. Electrical data is generated based on a quasi-periodic characteristic of electric peak sequences of the electrical signal. Acoustic data is generated based on a quasi-periodic characteristic of acoustic peak sequences of the acoustic signal, wherein the electrical data is combined with the acoustic data to provide an operation status of the at least one compartment.

The present disclosure relates to a detection circuit 200 for detecting oscillations of a regulated supply signal 110. The detection circuit includes a filter circuit 210 to filter the regulated supply signal in order to obtain a filtered supply signal 212. A peak value detector circuit 220 is designed to detect an extreme value of the filtered supply signal. A comparator circuit 230 is designed to compare the detected extreme value with a threshold value and to indicate an understepping or exceedance of the threshold value.

An MPU sequentially selects one from six energization patterns, applies constant voltage rectangular pulses to the three-phase coils for a prescribed sensing energization time, turns on at least the low-side arm of the three-phase half-bridge type inverter circuit so as to reflux an induced current between a switching element and the coils and attenuate the same, measures peak coil current values immediate before completing the sensing energization by an A/D-converter circuit, and stores the peak coil current values as measured data.

An MPU sequentially selects one from six energization patterns, applies constant voltage rectangular pulses to the three-phase coils for a prescribed sensing energization time, turns on at least the low-side arm of the three-phase half-bridge type inverter circuit so as to reflux an induced current between a switching element and the coils and attenuate the same, measures peak coil current values immediate before completing the sensing energization by an A/D-converter circuit, and stores the peak coil current values as measured data.

According to an embodiment, a multiphase regulator includes a plurality of output phases each of which is operable to deliver a phase current through a separate inductor to a load connected to the output phases via the inductors and an output capacitor. A controller is operable to regulate a voltage delivered to the load by adjusting the phase currents delivered to the load by the output phases, monitor the phase currents delivered to the load by the output phases, test the output phases in a predetermined sequence, and determine if the phase currents respond in a predetermined way.