Abstract: A circuit system for detecting a time-variable amplitude via an electric potential-difference to be detected. A first potential-difference detection device for detecting the at least one electric potential-difference and for outputting a first potential-difference signal, and a second potential-difference detection device for detecting the at least one electric potential-difference and for outputting a second potential-difference signal are provided. The first potential-difference detection device has a higher time resolution than the second potential-difference detection device, while the second potential-difference detection device has a higher amplitude resolution than the first potential-difference detection device.

Abstract: A method of collecting data from an optical channel monitor for monitoring the power of a wavelength-division multiplexed light signal at each wavelength is disclosed. The total light power is analog-to-digital converted by an A/D converter. The data of the total light power which has been analog-to-digital converted is compared with a reference light power by a comparator for each conversion, and when the difference between the total light power and the reference light power exceeds a predetermined threshold, a power fluctuation flag is turned ON. After the comparison, the above process of the analog-to-digital conversion and the comparison is iterated until the optical channel monitor completes the data collection for each wavelength. Thereafter, the processor determines whether the power fluctuation flag is ON or not. When the power fluctuation flag is ON, the processor discards the currently collected data and maintains the data which were collected immediately before.

Abstract: A digital multimeter displays a miniature version of a live actual reading of the multimeter. The miniature version typically appears after a larger version of the live actual reading is displaced by other display elements. The miniature version of the live actual reading may be accompanied by a warning icon or other graphical symbol to alert a user of a potentially hazardous electrical condition.

Abstract: Disclosed herein is a Fourier transform-based phasor estimation method and apparatus capable of eliminating the influence of exponentially decaying DC offsets. According to a Fourier transform-based phasor estimation method according to an embodiment of the present invention, an input signal is sampled, and samples of one-cycle data of the input signal are separated into at least two sample groups. A Discrete Fourier Transform (DFT) is performed on each of the sample groups. A DC offset included in the input signal is calculated on a basis of results of the DFT on each of the sample groups, and an error caused by the DC offset is calculated using the calculated DC offset. A phasor of a fundamental frequency component included in the input signal is estimated by eliminating the calculated error, caused by the DC offset, from the results of the DFT on the input signal.

Abstract: An electrical current measurement system. A sense impedance and a composite amplifier are in electrical communication and together define a trans-impedance circuit that presents a frequency-compensated impedance lower than the sense impedance to an input electrical current to be measured. A sense amplifier in electrical communication with the sense impedance provides an output indicative of a magnitude of the input electrical current. A current bypass circuit may parallel the trans-impedance circuit and bypass the input electrical current around the trans-impedance circuit when the current reaches a predefined magnitude. The system may be combined with another current sensor to form a dual-range current measurement instrument.

Abstract: This invention provides a clamp meter with safe trigger mechanism which allows an operator to take electrical measurements of the conductors safely, particularly in case of the electrical conductor elements situated in congested or awkward locations and positions. In the preferred embodiment of the present invention, the trigger is placed at the underside of said clamp meter so as to allow convenient access to it for the fingers of a hand while the clamp meter is held in the hand. The trigger mechanism of the invention may be operated with single or multiple fingers. The invention also allows the hand to maintain its ‘clinched-fist’ position throughout the measurement process, thereby eliminating the need to open the hand any time during the process. The invention thus makes the electrical parameter measurement operation using clamp meters safer than for the conventional meters.

Abstract: An electrical current measurement system. A first low-range current gauge receives a current to be measured and provides a first intermediate value indicative of the amplitude of the current up to a first maximum current. A second low-range current gauge receives any portion of the current having a magnitude that exceeds the first maximum current and provides a second preliminary value indicative of the amplitude of the portion of the current having a magnitude that exceeds the first maximum current up to a second maximum current. An arithmetic unit or a digital processor receives the first intermediate value and the second preliminary value and provides a second intermediate value indicative of the amplitude of the current. A full-range current gauge may also be provided. A selector or the digital processor selects one of the values for display or other output.

Abstract: A display device for a vehicle that display an amount of a particulate matter collected in a filter device for exhaust gas purification. A vehicle 1 includes distance storage apparatus 46 for storing a travel distance, a filter device 5 for exhaust gas purification for trapping a particulate matter contained in an exhaust gas, and collected amount detection apparatus 25 for finding an amount of the particulate matter collected in the filter device 5 for exhaust gas purification. A display control unit 42 normally acquires a travel distance from the distance storage apparatus 46 and displays the travel distance as a numerical value on a segment display unit 41, and when instructed to display a collected amount of the particulate matter, the display control unit 42 acquires a collected amount from the collected amount detection apparatus 25 and lights up the number of segment groups 61 corresponding to the collected amount, thereby displaying the collected amount.

Abstract: An avometer includes a measurement main body. The measurement main body includes a rotary knob for selecting a measurement item, a display, and a navigator. The rotary knob is used for an operator to select one of a current measurement mode, a voltage measurement mode, a resistance measurement mode, and a diode measurement mode before performing an operation. The display is used for displaying information and measured data of the measurement mode selected by the rotary knob. The navigator is used for switching the information of the measurement mode, and displaying the information on the display.

Abstract: The multimeter of the invention includes main body, a current sensor and a flexible tube. The main body is provided with a display. The current sensor is electrically connected to the main body via a wire. The flexible tube is connected between the main body and current sensor. And the wire is accommodated in the flexible tube. Therefore, the current sensor can be adjusted to any direction, angle and position.

Abstract: A digital multimeter comprises a rotary switch and a rotary switch memory. The rotary switch can be moved between a plurality of positions to change the function performed by the digital multimeter. When the rotary switch is in a particular position, a user can change the function currently associated with that position from a default function to a non-default function. Thereafter, when the user moves the rotary switch away from the particular and then subsequently moves the position back to the particular position, the multimeter resumes the non-default function without requiring further user-input.

Abstract: A circuit system for detecting a time-variable amplitude via an electric potential-difference to be detected. A first potential-difference detection device for detecting the at least one electric potential-difference and for outputting a first potential-difference signal, and a second potential-difference detection device for detecting the at least one electric potential-difference and for outputting a second potential-difference signal are provided. The first potential-difference detection device has a higher time resolution than the second potential-difference detection device, while the second potential-difference detection device has a higher amplitude resolution than the first potential-difference detection device.

Abstract: A method of a portable electronic device for self-calibration of a proximity sensor. A background measurement is obtained by the proximity sensor and a detection threshold of the proximity sensor is adjusted based on the background measurement. The background measurement is a measure of a received signal when no signal is transmitted by the proximity sensor, and the detection threshold is associated with a sensitivity of the proximity sensor to environmental conditions. A source signal is emitted by the proximity sensor based on the adjusted detection threshold of the proximity sensor, and a return signal is received by the proximity sensor corresponding to the source signal. A function of the portable electronic device may be performed base don the received return signal.

Abstract: A multimeter having measurement terminals and configured to receive measurement signals applied to the measurement terminals and a measurement value and also configured to receive communication signals applied to the measurement terminals and extract encoded information from the communication signals. The multimeter can be included in a multimeter communication system having a device coupled to the measurement terminals of the multimeter. The device is configured to generate communication signals having encoded information and provide the communication signals to the measurement terminals of the multimeter.

Abstract: A multimeter comprises a case having a circuit board located therein. The circuit board has a top side and a bottom side. A shield arrangement is configured to cover at least a portion of the top side and the bottom side of the circuit board. The shield arrangement includes a top shield part adjacent to the top side of the circuit board and a bottom shield part adjacent to the bottom side of the circuit board. The shield arrangement also includes a connecting structure by which the top shield part is interconnected with the bottom shield part. The connecting structure preferably forms at least one hinge configured such that the top shield part and the bottom shield part can be moved between open and closed configurations. Often, a plurality of hinges will be provided.

Abstract: There is provided a waveform observing apparatus with a reduced depth in such a manner that the waveform observing apparatus is one including a terminal board, connecting wiring extending from external equipment, a memory for receiving measured data through the terminal board, to store the measured data, and a display for displaying the measured data in waveform, the apparatus including: a first intra-body substrate, installed in an erect state inside a body frame of the waveform observing apparatus; a plurality of first connectors, provided on the first intra-body substrate; and a measurement module, which is connector-connected to the first connector of the first intra-body substrate, to be installed between the first intra-body substrate and the terminal board, and also includes a measurement circuit, wherein a plurality of measurement modules are detachable in an aligned state with respect to the erect first intra-body substrate.

Abstract: A digital multimeter can be monitored from a remote location via an on-board light source such as a backlight LED. The digital multimeter has memory, a processor operatively coupled to the memory, a light operatively coupled to the processor and the memory and a light sensitive sensor operatively coupled to the machinery and positioned proximate the light. The processor is configured to produce a first data signal containing information about the machinery, which is then modulated by the light so that the light blinks between an on state and an off state. The sensor is configured to detect the light on state and the light off state and convert the received light into a second data signal representative of the first data signal.

Abstract: The invention relates to a method and a device for measuring a first voltage and a second voltage by means of a differential voltmeter. The differential voltmeter comprises a first inlet and a second inlet and a known voltage potential is applied to the second inlet. The voltage measurement comprises the following; a first voltage is applied to a first inlet of the differential voltmeter, a first differential voltage is measured, the first voltage from the measured first differential voltmeter and the known voltage potential is determined, the second voltage is applied to the second inlet of the differential voltmeter, a second differential voltage is measured, and the second voltage from the measured second differential voltage and the previously determined first voltage is determined.

Abstract: A multimeter has a plurality of control panels, a display screen that can change display orientation, and/or a magnetic portion to releasably support the multimeter.

Abstract: A multimeter having measurement terminals and configured to receive measurement signals applied to the measurement terminals and a measurement value and also configured to receive communication signals applied to the measurement terminals and extract encoded information from the communication signals. The multimeter can be included in a multimeter communication system having a device coupled to the measurement terminals of the multimeter. The device is configured to generate communication signals having encoded information and provide the communication signals to the measurement terminals of the multimeter.

Abstract: A system and method for providing an additional option function to existing functionality of a meter device configured for measuring parameters of energy is provided. The meter device is coupled with an option device for exchanging data between the meter and the option devices along at least one data path, including exchanging initialization data provided by the option device between the meter device and the option device, wherein the initialization data is useable by the meter device for configuring the meter device to be in condition to operate with the option device. The data exchanged between the meter device and the option devices are processed by at least one processor. Upon the coupling of the devices and the exchanging of the initialization data, the meter device is operated with the option device for adding the option function to existing functionality of the meter device.

Abstract: A method for increasing the availability of displacement/position measuring systems using a potentiometer with a slider tap in a closed control loop. The controller of the potentiometer is formed by a microcontroller which is supplied with the position of the slider via an analog/digital converter. The operating range is shifted within the sensor range in a direction of one of two limits of the operating range at least by a distance between the other of two limits of the operating range and a defective slider position by temporarily interrupting an operative connection between the displacement pick-off on the actuator and the potentiometer shaft.

Abstract: Diagnosing electrical circuit faults can be accomplished with a variety of tools. Voltmeters are frequently used to measure voltage to determine whether a short is present, but are not well-suited for finding intermittent faults caused by corroded connectors or excessive voltage drop under operating loads. Measuring a static voltage without load using a voltmeter can yield misleading results. A diagnostic tool that is simple to use and that yields a definitive result is preferred in certain applications such as automotive electrical system diagnosis due to the varying skill level of technicians and the variation in field conditions in automotive shops. A simple, inexpensive diagnostic tool that can be used with minimal or no training allows rapid diagnosis of circuit faults that result from a the inability of a measured circuit to supply a minimum current at a minimum voltage.

Abstract: A multimeter includes a switching circuit. The switching circuit includes a micro control unit (MCU), a first normally-open switch, a second normally-open switch, and an electronic switch. The first and second normally-open switches connect to the MCU. The MCU connects to the electronic switch. The electronic switch connects to a power control terminal of the multimeter. The MCU are operable to detect whether the first and second normally-open switches are both closed and accordingly control the electronic switch to turn on or off. The electronic switch outputs a control signal to the power control terminal of the multimeter to control the multimeter to power on or off.

Abstract: The present invention provides a clamp meter with clamp jaws whose position is adjustable in different planes with respect to the plane of the main body of the clamp meter at various fixed angles, thereby helping the user to measure the current in the conductors which are disposed in tight physical spaces such as an electrical cabinet or electrical panel, or placed in awkward positions such as overhead locations. The present invention allows the user to operate the instrument and also read the display in all positions of the clamp jaws.

Abstract: An electrical current measurement system. A first low-range current gauge receives a current to be measured and provides a first intermediate value indicative of the amplitude of the current up to a first maximum current. A second low-range current gauge receives any portion of the current having a magnitude that exceeds the first maximum current and provides a second preliminary value indicative of the amplitude of the portion of the current having a magnitude that exceeds the first maximum current up to a second maximum current. An arithmetic unit or a digital processor receives the first intermediate value and the second preliminary value and provides a second intermediate value indicative of the amplitude of the current. A full-range current gauge may also be provided. A selector or the digital processor selects one of the values for display or other output.

Abstract: A range-changing circuit for a measurement device having a desirable range includes an array of graduated impedances. And amplifier supplies an electrical voltage to at least one of the impedances of the array. A voltage sensing and limiting switch is provided in a feedback path of the amplifier. The switch limits said electrical voltage supplied to said at least one of the impedances in response to a sensed voltage that is sensed by the switch. An electrical voltage in the desirable range is developed across a different one of the impedances of the array based on an operation of the switch.

Abstract: An electrical current measurement system. A sense impedance and a composite amplifier are in electrical communication and together define a trans-impedance circuit that presents a frequency-compensated impedance lower than the sense impedance to an input electrical current to be measured. A sense amplifier in electrical communication with the sense impedance provides an output indicative of a magnitude of the input electrical current. A current bypass circuit may parallel the trans-impedance circuit and bypass the input electrical current around the trans-impedance circuit when the current reaches a predefined magnitude. The system may be combined with another current sensor to form a dual-range current measurement instrument.

Abstract: In one embodiment, a measurement apparatus has an input stage, an output stage and a multiplexer. The input stage has a signal input, a plurality of measurement range outputs, and a plurality of selectable gain stages, with each of the selectable gain stages being coupled between the signal input and a respective one of the measurement range outputs. The output stage has a measurement acquisition path between an analog measurement input and a digital measurement output. The measurement acquisition path includes an analog-to-digital converter. The multiplexer has i) a plurality of data inputs, at least two of which are coupled to respective ones of the plurality of measurement range outputs, and at least one of which is a reference input configured to receive a signal to which signals appearing at the measurement range outputs are commonly referenced, ii) a data output coupled to the analog measurement input of the output stage, and iii) a control input.

Abstract: An electrical meter is provided that includes a cover configured for securement onto a base. The meter includes features that resist meter tampering, and features that provide evidence of meter tampering.

Abstract: A testing device including low-pass filter with automatically switching function is disclosed in the present invention, comprising: a control circuit used to control the operation of the testing device and provide a reference frequency (Fr); a frequency detection circuit, connected to the input end and the control circuit and used to output a high frequency control signal; a low-pass filter connected to the frequency detection circuit, used to filter the testing signal of the input end to output a frequency signal; a frequency evaluation circuit connected to the control circuit and to the frequency signal outputted from the low-pass filter, the frequency evaluation circuit outputting a medium frequency control signal to the low-pass filter and outputting a frequency testing value to a display at the same time; and a voltage measuring circuit, connected to the low-pass filter and the control circuit and used to output a voltage measuring value to the display.

Abstract: A digital multimeter can be monitored from a remote location via an on-board light source such as a backlight LED. The digital multimeter has memory, a processor operatively coupled to the memory, a light operatively coupled to the processor and the memory and a light sensitive sensor operatively coupled to the machinery and positioned proximate the light. The processor is configured to produce a first data signal containing information about the machinery, which is then modulated by the light so that the light blinks between an on state and an off state. The sensor is configured to detect the light on state and the light off state and convert the received light into a second data signal representative of the first data signal.

Abstract: A multimeter comprising a base unit having at least one test lead terminal. A remote display unit separate from the base unit is also provided. The remote display unit has a display operative to show measured parameters. The multimeter further comprises communication circuitry operative to provide electrical communication between the base unit and the remote display unit. The communication circuitry provides electrical communication in a plurality of alternative communication modes. At least two of the alternative communication modes are preferably wireless communication modes.

Abstract: A method of a portable electronic device for self-calibration of a proximity sensor. A background measurement is obtained by the proximity sensor and a detection threshold of the proximity sensor is adjusted based on the background measurement. The background measurement is a measure of a received signal when no signal is transmitted by the proximity sensor, and the detection threshold is associated with a sensitivity of the proximity sensor to environmental conditions. A source signal is emitted by the proximity sensor based on the adjusted detection threshold of the proximity sensor, and a return signal is received by the proximity sensor corresponding to the source signal. A function of the portable electronic device may be performed base don the received return signal.

Abstract: A measuring device with the function of automatically determining the type of device under test (DUT) and selecting measuring function. The measuring device having a controller for sequentially providing a plurality of checking phases; a protection circuit connecting to input end and protecting the measuring device; a switch composed of a plurality of test circuits, being connected to the controller and sequentially connecting the plurality of test circuits with the output end of the protection circuit; a plurality of DUT type detectors, connecting to the switch and comparing the voltage of input end sequentially through a plurality of comparison circuits, transmitting the result of comparison to the controller for determining the type of DUT; and a measurement unit connecting to the controller, measuring the DUT according to the result of determination of the controller and displaying the result of measurement on a display.

Abstract: An electrical to audible signal measurement apparatus comprises an absolute value converter, a voltage to frequency converter, a polarity detector, and a waveform changer. The absolute value converter is capable of converting a bipolar input signal into a unipolar signal. The voltage to frequency converter is connected to the absolute value converter and is capable of generating a frequency signal proportional to the unipolar signal. The polarity detector is capable of identifying a polarity of the bipolar input signal to form an identified polarity. The waveform changer is connected to the voltage to frequency converter and polarity detector and is capable of generating a number of different waveforms in an audio frequency range in response to receiving the frequency signal from the voltage to frequency converter and in response to the identified polarity.

Abstract: An AC/DC voltage measuring instrument is operable in a DC mode, an AC mode, or an automatic mode. In the DC mode, an input terminal is coupled directly to an analog-to-digital converter, which generates a digital output signal indicative of the amplitude of the received signal. In the AC mode, the input terminal is coupled to an RMS circuit through a capacitor. The RMS circuit generates an output signal having an amplitude indicative of the RMS amplitude of the received signal, and this output signal is coupled to the analog-to-digital converter. In the automatic mode, the input terminal is also coupled to the RMS circuit, but it is coupled to the RMS circuit without being coupled through the capacitor. The input terminal is coupled to the RMS circuit through an amplifier, and a calibration procedure is used to compensate for any offset of the amplifier.

Abstract: A digital multimeter having improved recording functionality is disclosed. The digital multimeter disclosed incorporates a rotary switch, a series of keys and buttons, and a digital display so as to provide highly integrated, programmable and configurable features. Several of these features, either taken alone or in combination, provide significant improvements in ease of use, speed of user operation, and safety associated with use of the instrument.

Abstract: A method for evaluating uncertainty associated with the value of a measurand derived from measurements of a device under test is disclosed. A mathematical model is provided wherein the measurand is expressed as a function of (i) at least one physically observable quantity, and (ii) the reference value of the physically observable quantity in a reference device. The reference value of the reference device and the value of the measurand of the device under test are measured. The value of the at least one physically observable quantity is also measured. At least one uncertainty value is determined as a function of the physically observable, wherein the mathematical model takes into account the at least one source of uncertainty and the reference value of the reference device.

Abstract: A multimeter for testing a plurality of electrical parameters comprises a case having a plurality of test lead jacks. Each of the test lead jacks includes a unitary conductive socket. Preferably, the sockets are made of metal such as brass. A circuit board located in the case has jack conductors in electrical communication with each of the sockets. A jack detection arrangement is adapted to automatically determine whether a plug is inserted into a respective one of the sockets based on a change in electrical characteristics. For example, the jack detection arrangement may include a photonic emitter and a photonic detector situated such that a beam path therebetween is interrupted by insertion of a plug. The case may further have a rotary selector knob for selecting a multimeter function.

Abstract: The current measuring device comprises a first measuring resistor to receive a measurement current, and a first signal amplifier having an input connected to said first measuring resistor and an output to provide a first measurement signal. A second measuring resistor is connected in series with said first measuring resistor, and first voltage limiting means are connected in parallel on the first measuring resistor to branch a first shunt current off when a first limiting voltage is reached on said first measuring resistor. The value of the first measuring resistor is greater than the value of the second measuring resistor A processing unit comprises one such current measuring device.

Abstract: A method and apparatus for detecting at least two process variables in a loop powered circuit. The method includes the steps of (a) powering the loop, detecting a first process variable value during a first time interval, (b) detecting a second process variable value during a second time interval after the expiration of the first time interval, where the detected process variable values are represented by the magnitude of a current passing through the loop circuit.

Abstract: A digital multimeter with a rotary switch having a plurality of positions, each of the positions corresponding to a primary measurement function to be performed. An LCD displays secondary functions or modes corresponding to the positions of the rotary switch and values determined by performing one of the measurement functions. The multimeter includes default functions for each position of the rotary switch that may be changed to other functions or modes. When the other functions or modes are set in a first position, the rotary switch is moved to a second position, and returned to the first position the multimeter restores the functions and/or modes set when the rotary switch was previously in the first position.

Abstract: A digital multimeter comprising measured object input terminal, conversion circuit of fast analog/digital converter, microprocessor, auxiliary program-controlled voltage or current source, potential-divider network, electronic switches, and display. Compared with conventional multimeters, the adoption of fast analog/digital conversion technology as well as method that applies auxiliary power supply at the time of passive analog amount measurement allows for measurement of different responses between input terminals after auxiliary power supply is applied, thus being able to automatically determine the characteristics and size of the measured object.

Abstract: A range-changing circuit for a measurement device having a desirable range includes an array of graduated impedances. And amplifier supplies an electrical voltage to at least one of the impedances of the array. A voltage sensing and limiting switch is provided in a feedback path of the amplifier. The switch limits said electrical voltage supplied to said at least one of the impedances in response to a sensed voltage that is sensed by the switch. An electrical voltage in the desirable range is developed across a different one of the impedances of the array based on an operation of the switch.

Abstract: A multimeter having measurement terminals and configured to receive measurement signals applied to the measurement terminals and a measurement value and also configured to receive communication signals applied to the measurement terminals and extract encoded information from the communication signals. The multimeter can be included in a multimeter communication system having a device coupled to the measurement terminals of the multimeter. The device is configured to generate communication signals having encoded information and provide the communication signals to the measurement terminals of the multimeter.

Abstract: An electrical test lead for use with a multi-meter has a fuse assembly adapted to releasably hold a fuse in-line of the electrical wire connecting ends of the electrical test lead. The fuse assembly may be permanently attached to the electrical test leads or may be releasably attached at one or both ends thereof to electrical test lead sections. The fuse assembly includes a fuse holder that is preferably clear to see the replaceable fuse therein in order to determine whether the fuse has blown. The electrical test lead has a fuse assembly holding a replaceable fuse electrically connected to and situated between a first test lead section terminating in a test lead plug that is adapted to be received in a test lead receptacle of a multi-meter and a second test lead section terminating in one of an electrical test probe and a test lead receptor adapted to receive a test lead tool.

Abstract: A device for measuring current comprises a magnetic field sensor for measuring the magnetic field produced by a current I flowing through a current conductor and a yoke of a magnetic material with a relative permeability of at least 100. The magnetic field sensor preferably comprises a semiconductor chip with at least one Hall element and an electronic circuit for the operation of the Hall element. The yoke consists of an oblong piece of sheet metal or a laminate of sheet metals with two ends, that has been brought by bending into a form in which the front sides of the ends of the yoke face each other and are separated by an air gap. The ends of the yoke may be flush, tapered, or flayed relative to the width of the yoke.

Abstract: A digital multimeter automatically records measurements of electrical or physical parameters. The multimeter may record the measurements based on events such as the passage of time, fluctuations or deviations in the measurements, or user inputs. In some examples, the digital multimeter operates at a reduced power setting during automatic recording operations.

Abstract: An ammeter for ATE instrumentation includes an amplifier, a first current measuring circuit coupled to the amplifier's power supply leads, and a second current measuring circuit coupled to the amplifier's output. The first current measuring circuit is used to select a desired current measurement range, away from the amplifier's output. Output transients caused by range changes are therefore avoided. The ammeter's response to load transients is also minimized, by providing smooth transitions between low current and high current operation.