234results about "Automatic balancing arrangements" patented technology

A system for generation of electrical power including an inverter connected to a photovoltaic source including a theft prevention and detection feature. A first memory is permanently attached to the photovoltaic source. The first memory is configured to store a first code. A second memory is attached to the inverter. The second memory configured to store a second code. During manufacture or installation of the system, the first code is stored in the first memory attached to the photovoltaic source. The second code based on the first code is stored in the second memory. Prior to operation of the inverter, the first code is compared to the second code and based on the comparison; the generation of the electrical power is enabled or disabled.

A current sensor includes a deflectable member disposed in a magnetic field. Nulling or compensating members may be mechanically coupled to the deflectable member. Feedback or readout devices coupled to the structure provide signals indicative of deflection of the deflectable member under the influence of applied current and the magnetic field. Nulling current applied to the nulling members tends to oppose deflection of the deflectable member. The nulling current may be modulated to drive the feedback signal to a desired level and is used as a basis for calculating the current to be measured. The current may be measured directly upon calibration of feedback devices coupled to the deflectable member or to the nulling members. Arrays of sensors may be coupled to common busses for applying measured and nulling currents to sensors of the arrays and for detecting feedback signals.

One embodiment of the present invention relates to a method and apparatus to perform a low power activation of a system by measuring the slope of a digital signal corresponding to a motion sensor measurement value. In one embodiment, a low power activation circuit is coupled to magnetic motion sensor configured to output a magnetic signal proportional to a measured magnetic field. The low power activation circuit may comprise a digital tracking circuit configured to provide a digital signal that tracks the magnetic field and a difference detector configured to detect a difference between a current digital signal and a prior digital signal stored in a digital storage means. If the detected difference is larger than a digital reference level, an activation signal is output to awaken a system from a sleep mode.

An apparatus, system, and method are disclosed for determining power source failure. A sampling module samples an alternating current power waveform as input to a power supply, at a sampling frequency which is a multiple of a predetermined frequency, to obtain a sampled amplitude at a known point within the predetermined period. A comparison module compares the sampled amplitude to a stored threshold amplitude to obtain a comparison result, corresponding to the known point. An accumulation module accumulates most recent comparison results. A warning module asserts an early power off warning signal if a predetermined number of the most recent comparison results each indicate that the sampled amplitude is smaller in absolute value than the stored threshold amplitude.

A current sensor includes a sensing circuit for sensing current and supplying indications thereof. The current sensor also includes two or more output terminals coupled to the sensing circuit that alternately supply respective indications of the sensed current according to control signals supplied to the current sensor.

Current measurement apparatus comprises a measurement arrangement and a signal source. The measurement arrangement is configured to measure a current signal drawn by a load. The signal source is operative to apply a reference input signal to the measurement arrangement whereby an output signal from the measurement arrangement comprises a load output signal corresponding to the load drawn current signal and a reference output signal corresponding to the reference input signal. The signal source comprises a current multiplier which defines first and second current paths and is configured such that: the first path carries a multiplier input current signal; the second path carries a multiplier output current signal which determines the reference input signal and which corresponds to the multiplier input current signal multiplied by a multiplier value determined by the current multiplier; and the multiplier input current signal and the multiplier output current signal are carried on their respective paths in a same direction relative to a power supply voltage. Power drawn through the second path as divided by the multiplier value is less than the power drawn through the first path.

A digital multi-meter (DMM) is described which can be inserted into a peripheral device card expansion slot of a personal digital assistant (PDA) to provide the PDA with DMM functionality. The DMM is configurable by configuration data supplied by application software running on the PDA. Configuration of the DMM may include, for example, setting measurement function and input ranges. The DMM internal circuitry measures input signals, digitizes them and supplies them to the PDA for display and/or storage. This allows for a data acquisition unit which combines a DMM with the computing power of a PDA. The PDA may be programmed to display or store data in a multitude of ways, depending on the requirements of a particular application. The combined DMM and PDA may benefit from various other functions of the PDA, for example wireless communication of data to allow remote data logging.

An overcurrent detection apparatus includes a sense emitter current detection unit that detects a sense emitter current output from a sense emitter of an IGBT as a sense emitter voltage, and a comparison unit that detects an overcurrent by comparing the sense emitter voltage detected by the sense emitter current detection unit with a threshold voltage. The overcurrent detection apparatus also includes a correction current detection unit that detects a correction current corresponding to a current flowing between a gate and the sense emitter of the IGBT as a corrected voltage; and a voltage correction unit that calculates a sense emitter corrected voltage by subtracting the correction voltage detected by the corrected current detection unit from the sense emitter voltage detected by the sense emitter current detection unit, and supplies the sense emitter corrected voltage to the comparison unit.

Electrical faults are detected in electrical distribution systems (EDS) by detection and location of radio frequency (RF) emissions generated by the fault with multiple time-synchronized radio frequency monitors (RFM) distributed about the EDS. The RFMs are coupled to a self-learning, electrical fault monitor (EFM) that characterizes and/or locates electrical faults based on operating state (OS) patterns learned from transmission of test signals generated within the EDS. RF emissions data samples are characterized as safe operation (SO) states or potential electrical faults by accessing a base of stored knowledge concerning fault emission characteristics and/or synchronized time of arrival at each RFM. Information in the base of stored knowledge is updated to include new EDS operating states (OS). Confidence level associations, location of new radio frequency emission patterns and whether those patterns are indicative of safe operating (SO) conditions or electrical faults are stored in the base of stored knowledge.

The present invention relates to electrical measurement apparatus (10). The electrical measurement apparatus (10) comprises a measurement arrangement (20,24) configured to be disposed in relation to an electrical circuit (12,14,16,18) which bears an electrical signal, the measurement arrangement (20,24) being operative when so disposed to measure the electrical signal. The electrical measurement apparatus (10) further comprises a signal source (22) operative to apply a reference input signal to the measurement arrangement (20,24) whereby an output signal from the measurement arrangement comprises an electrical output signal corresponding to the electrical signal and a reference output signal corresponding to the reference input signal, the reference input signal having a substantially piecewise constant form which is repeated over each of plural cycles. The electrical measurement apparatus (10) yet further comprises processing apparatus (26) which is operative: to determine at least one cumulative representation, determination of the cumulative representation comprising summing plural received sections of the output signal, each of the plural received sections corresponding to at least a part and to a same part of the cycle of the reference input signal; and to determine at least one of: a transfer function for the measurement arrangement; a change in a transfer function for the measurement arrangement; and the electrical signal, in dependence on the at least one cumulative representation and the reference input signal.

Providing reliable testing of a device under test (DUT) by compensating for a reduced voltage inside the device without changing the internal circuitry of the device. The DUT has multiple connection terminals for connecting to the test equipment including at least first and second power connection terminals that both connect to an internal power bus of the DUT. An adapter board connects to the multiple connection terminals of the DUT via a removably attachable socket which holds the DUT. A tester supplies power to the DUT through the adapter board. The adapter board is configured to supply power from the tester to the DUT through the first power connection terminal and to monitor voltage at the second power connection terminal. The tester includes a compensation unit which controls power based on the voltage monitored at the second power connection terminal.

A circuit and a method for sensing differential capacitance involve using plural storing capacitors to repeatedly sample charges of the differential capacitance in an over-sampling manner, and storing the charges sampled in different transfer rounds into different storing capacitors instead of repeatedly transferring charges for a single storing capacitor, so as to collect charge averages about both inputs and noises and in turn effectively reduce RF interference and source noises.

One or more embodiments are directed to a resistance bridge having two voltage measurements circuits that function in tandem. In one embodiment, a constant current source may be applied to two resistors coupled in series, in which the first resistor has a known resistance and the second resistor has a resistance to be determined or verified. A first measurement circuit may measure a first voltage across the first resistor and at substantially the same time a second measurement circuit measures a second voltage across the second resistor. The voltage of each resistor is converted to a ratio. Based on the ratio and the resistance of the first resistance, the resistance of the second resistor may be calculated.