Abstract: A system for measuring differences in a physical variable, such as temperature or voltage, by utilizing predictable behavior in the relative time drift of offset curves for various circuit elements, including, for example, two sensors coupled to a difference signal amplifier, an ambient condition amplifier, and an analog to digital converter. In an initial calibration mode, the system records several offset curves, stored in memory, correlating ambient condition measurements to offset measurements acquired from the ambient condition amplifier and the difference signal amplifier. Offset curves recorded in the initial calibration mode, correlating ambient condition measurements to measurements from the difference signal amplifier, include one curve recorded with both inputs of the difference signal amplifier held at equal potential and another curve recorded with both sensors held at the same value of the physical variable, over a given ambient condition range.

Abstract: A hooking-type fully automatic electric meter with a function of fully automatic detecting and choosing a measuring mode among the electric current, voltage and resistance measuring modes. A user only needs to turn on the electric power of the electric meter without performing any other procedures; he can get an accurate reading of the volume of electricity on the display screen. The meter is different from the manually selected clamping type meters with different functional positions for measuring the values of electric current, voltage and resistance. With the meter, damage to the main body of the electric meter in operating electric measuring and to the safety of the user himself can be avoided. This can significantly raise the industrial safety in measuring large volume of electric current, and can save actions and time for operating the electric meter, and convenience and efficiency in operating can be increased.

Abstract: An electro-optical, automatic meter reader for enabling a consumer to view and manage power consumption through a browser. A sensor attached to a bracket is mounted to the outside cover of a utility meter without modification of the meter or removal of its housing. A data-collector stores data obtained from the sensor via a serial port which may also provide power for the sensor, thus avoiding use of a dedicated power supply. The data-collector connects to a computer which provides a centralized object through which to view and manage power consumption. The real-time and combined historic data can be used to forecast whether usage will fall above or below a predetermined usage level at the end of a given period of time. In response to a forecast exceeding the level, the computer displays the appropriate graph in a red colored bar within a quantity vs. time chart. The computer may control power consuming devices.

Abstract: A multi-range measuring circuit for measuring a flow of electrical current between a first node and a second node. A measurement resistor is connected to the first node to develop a voltage having a high range output. A summing node connected in series with the measurement resistor acts as an input to an amplifier for developing a second voltage having a low range output having a higher scale factor than the high range output. If the capacity of the amplifier to maintain the low range as a linear function is exceeded, a bypass circuit bypasses excess current flow to the second node.

Abstract: A passive device for the detection and indication of non-ionizing electromagnetic radiations and static electricity is provided. The device is especially designed to be applied to or integrated in an anti-radiation/anti-static/anti-reflection filter intended to block the aforementioned emissions, particularly in devices with cathode ray tubes(CRT).

Abstract: A single variable color display device simultaneously exhibits two distinct display units in a side by side relation. Two color controls are provided for illuminating the display units in respectively different colors so they could be readily distinguished.

Abstract: The invention relates to sensors for detecting a time-varying current by employing a plurality of coils with separate windings, disposed on separate toroidal cores, that are placed in close proximity of each other so that each coil responds independently to the same current. The current produces a time-varying magnetic field which in turn induces a plurality of voltages across the coils that can be combined to provide a resultant signal. Some embodiments of the invention employ coils with opposite windings to obtain signals with opposite phases and combine these signals through differential detection means to obtain a combined signal. One aspect of the invention relates to production of a wide-band or a selectable band-width sensor by preparing at least one coil to be dissimilar with respect to the others. In addition, the invention provides provisions for easy calibration of the sensor.

Abstract: A power meter includes components to measure RMS power over an 84 dB range or greater using the I-V square-law relation of a diode for measurements. The power meter includes multiple diodes along with a power distribution manifold which includes power dividers to distribute an input signal to the diodes. In one embodiment, a first power divider (202) distributes power to a first one of the diodes (203), and to the second power divider (204) which distributes power to the second (210) and third (212) diodes. The first power divider (202) is connected without attenuation to the first diode (203). The second power divider (204) is connected to the second diode (210) through a 11 dB attenuator (206), and to the third diode (212) through a 28 dB attenuator (208).

Abstract: The present invention provides a current sensor for an electrical device. The sensor includes a housing, a conductor routed through the housing, an array of current transducers coupled to the conductor, and a current level signal generated by the current transducers. The conductor is adapted to be connected in a current path of the electrical device. Each of the current transducers has an output lead. The current level signal is provided on said output leads. The output leads are electrically connected to a printed circuit board. An external connector is electrically connected to the printed circuit board through a cable. A plurality of shields are used adjacent to the current transducers. The array of current transducers can be a single layer array, a multiple layer array, or a planar array.

Abstract: A metering module has a housing, a metering circuit in the housing for receiving and processing at least one signal corresponding to an electrical quantity, and developing an output signal. A connector mounted to the said housing is coupled to the metering circuit, and configured for engagement with a mating connector at least one of a sensor array module and a mounting and connection base. Mounting structure is provided on the housing for removably mounting the housing to at least one of a sensor array module and a mounting and connection base. A circuit in the housing delivers voltage and current signals received at the first and second connectors to a further connector mounted on the housing. First and second mounting structures are provided for mounting the housing to a surface and for mounting a removable metering module.

Abstract: A two-terminal multimeter capable of both volt/ohm and current measurement employs an input protection circuit with a positive temperature coefficient impedance and a reference impedance, across which an A-D converter takes measurements. A current measurement signal activates a switch to ground one side of the reference impedance for taking current measurements. A controllable clamping switch grounds the positive temperature coefficient impedance in an input overload situation to provide input protection against damage to the meter components.

Abstract: Handheld electronic instrument for diagnosing the operating condition of a vehicle. The instrument is capable of performing the basic functions of a multimeter as well as able to test at least one system of a vehicle. This reduces the need for additional equipment that a technician must use and increases the efficiency and profitability of the technician. The instrument has a microprocessor, a memory storage for a computer program controlling the microprocessor and for other information, a display screen, a plurality of buttons, a rotary switch capable of being rotated by one finger of the operator of the instrument. The instrument has at least two display screens selections for monitoring and diagnosing a system of the vehicle, and each display screen has at least one operating mode for monitoring and diagnosing a function of the system, and the display screen selections are capable of being selected by the rotary switch.

Abstract: With added circuits and the computer's existing internal circuits and devices, a PC can function as a multimeter. For those users who are testing, designing or analyzing an electronic device, which requires the features of a computer and a multimeter, the subject invention provides convenience to the user. This subject invention will reduce or eliminate the cumbersome handling of two pieces of equipment on the same workbench.

Abstract: A wireless phasing voltmeter having a high impedance AC voltmeter in series with two high impedance probes. Shielding surrounds and electrically isolates the voltmeter and probes which communicate via wireless, FM transmission, thus eliminating the cable customarily used to connect the probes. The signal transmitted may be analog or digital. The transmitter and receiver may be plugged into the same jacks on the probe that were used for the cable. In parallel with the voltmeter and connected electrically with the shielding is an electrical circuit designed to add the capacitive current to a current detected by the probes in such a way that the net effect on the measured current is zero.

Abstract: A power booster and current measuring circuit provides a quiet, accurate voltage to a load (such as a transistor during parametric testing) with a load current of up to 1 ampere, and can measure that load current to an accuracy of ±0.1 % over a range of currents extending nine orders of magnitude (e.g., 1 ampere to 10−9 amperes). The load voltage is supplied by a sense driver, a bypass driver, or both. The bypass driver comprises a high-current operational amplifier with a direct feedback loop (e.g., a voltage follower). The sense driver comprises a high-impedance operational amplifier having a feedback loop comprising a high-current operational amplifier connected as a voltage follower and one of a series of sense resistors having different values.

Abstract: An electronic test instrument in the form of a clamp meter has a non-contact voltage sensing circuit which includes a blade and sensor built into the clamp. The test instrument also has a shaker circuit that produces a tactile vibration in the presence of an AC voltage. The intensity of the vibration is proportional to the level of the AC voltage. A clean power indicator circuit is provided as well. The clean power circuit compares the level of harmonic distortion plus noise to the full signal and activates an LED if the distortion plus noise is within acceptable limits.

Abstract: A multicolor display element includes a plurality of display areas arranged in a pattern, each including light emitting diodes of respective primary colors, which are coupled to the buses in accordance with their colors. A single enable input is provided for receiving an enable signal having an active level and an inactive level, for selectively extinguishing the entire display element and for illuminating the selected display areas in a desired color. The enable input jointly controls the conductivity of tri-state buffers which are respectively coupled to the buses.

Abstract: The invention relates to sensors for detecting a time-varying current by employing a plurality of coils with separate windings, disposed on separate toroidal cores, that are placed in close proximity of each other so that each coil responds independently to the same current. The current produces a time-varying magnetic field which in turn induces a plurality of voltages across the coils that can be combined to provide a resultant signal. Some embodiments of the invention employ coils with opposite windings to obtain signals with opposite phases and combine these signals through differential detection means to obtain a combined signal. One aspect of the invention relates to production of a wide-band or a selectable band-width sensor by preparing at least one coil to be dissimilar with respect to the others. In addition, the invention provides provisions for easy calibration of the sensor.

Abstract: An rms converter accommodates incoming signals of large crest factor by using an amplifier having a transfer function of non-uniform slope. The amplifier has a lower gain for larger signals. The output of the amplifier is converted to digital voltage values. The non-uniform gain of the amplifier is compensated for in digital calculations of the rms value. The invention produces accurate rms measurements by accurately measuring lower incoming signal voltages while still accommodating high peak voltages. The invention also reduces the dynamic range requirements for the analog to digital converter.

Abstract: A probe or accessory incorporating the features of the subject invention includes a communications arrangement for communicating topology-related data to a host instrument connected to the probe or accessory. The topology-related data describes the probe or accessory as a network comprising multiple paths from the probe tip to host instrument input connector. Each path is associated with a feature of the probe or accessory, and only one path may be active at any given time. Each feature is described by a unique number, called a “tag”. New tags may be assigned when necessary so long as existing tags are not disturbed. A probe or accessory in accordance with the subject invention transmits a list of “Required Tags” to the host instrument. Each required tag is associated with a pathway within the probe or accessory. The host instrument may only exercise those paths for which all required tags are understood, or those for which no required tag is designated.

Abstract: An apparatus and method for performing an auto-ranging function in electronics test equipment monitors both the RMS value and the peak value of the input signal to be measured. In the subject system, a peak signal measurement which exceeds the dynamic range of the currently-selected range will cause selection of the next higher range. A peak signal measurement which would exceed the dynamic range of the next lower measurement range, will prevent selection of the next lower range when the RMS value would otherwise have caused that selection. A peak signal value which does not exceed the dynamic range of the currently-selected measurement range, or the dynamic range of the next lower measurement range will allow control of measurement range selection to be determined by the RMS value of the input signal.

Abstract: A power meter includes components to measure RMS power over an 84 dB range or greater using the I-V square-law relation of a diode for measurements. The power meter includes multiple diodes along with a power distribution manifold which includes power dividers to distribute an input signal to the diodes. In one embodiment, a first power divider (202) distributes power to a first one of the diodes (203), and to the second power divider (204) which distributes power to the second (210) and third (212) diodes. The first power divider (202) is connected without attenuation to the first diode (203). The second power divider (204) is connected to the second diode (210) through a 11 dB attenuator (206), and to the third diode (212) through a 28 dB attenuator (208).

Abstract: An interactive dive apparatus for use by a scuba diver to determine a maximum dive duration, including an input interface for inputting dive specific parameters including a J-factor for adjusting a no-stop time calculation to compensate for various environmental and physiological parameters, a clock for determining an elapsed dive time, and a depth sensor for detecting a present depth and a maximum depth. The depth sensor tracks diver dwell time in each of plural predetermined depth ranges, and a CPU determines a no-stop time in accordance with the user inputted dive specific parameters and the detected dwell time. The interactive dive apparatus further includes a display screen for displaying at least the no-stop time, elapsed dive time duration and the current depth.

Abstract: A method for continuously controlling color of a display device comprises the steps of receiving three sets of data respectively representing the portions of three primary colors, accumulating three counts in accordance with the data, respectively, and setting three bistable devices for the respective durations of the accumulating. The outputs of the three bistable devices are coupled for respectively energizing three buses, to which the light emitting diodes of three primary colors are connected in accordance with their colors, for controlling the portions of the light signals of the primary colors emitted therefrom.

Abstract: A continuously variable color display system includes a plurality of display areas, each including three light emitting diodes, for emitting light signals of respectively different primary colors, which are controlled by three bistable devices, respectively. Each bistable device is set at the beginning of a time interval, defined by a corresponding input digital code, and reset at the end of the time interval. Accordingly, the light emitting diodes jointly illuminate in a composite color determined by three input digital codes.

Abstract: A dual mode power meter provides a first operation mode in the square law operating range of the diode, and a second mode in the square law region as well as the transition and linear operating ranges of the diode. The power meter includes multiple diodes. A manifold made up of power dividers distributes a signal input to the power meter to the diodes. A different attenuation is provided to each diode so that the square law operating range for each diode covers a different power range. By selecting the appropriate diode output for power measurements in the first mode, the overall square law operating range for the power meter will be greater than a power meter using a single diode. The power meter further includes a memory map of voltage vs. power in the square law, transition and linear regions of a diode measured for an unmodulated CW input for the second operation mode. The map of voltage vs.

Abstract: A passive voltmeter for high voltage transmission lines that accurately measures and displays a wide range of voltages. A d'Arsonval type meter movement is preferably used in conjunction with the voltmeter wherein the scale contains a linear range and a compressed, nearly-logarithmic range. A circuit controls the pointer so that the deflection is linear for a low range of voltages while a high range of voltages is deflected in a compressed manner. The term “compressed” means that the display is scaled in a logarithmic manner although not a true logarithmic function. The circuit comprises one or more parallel branches with a meter movement and a resistor in the first branch; each additional branch, if more than one, contains a resistor and at least one diode connected in series.

Abstract: An apparatus and method useful in a test and measurement instrument for selecting a particular television field for display, determines the television system standard from the input signal, uses the standard selection to determine the time for one field, and multiplies the field rate by an operator-supplied number of fields to calculate the required holdoff time. The subject invention relieves the operator from turning the holdoff control multiple times, and also relieves the operator from having to calculate the time delays for any of one to seven fields of holdoff (in the case of a PAL signal).

Abstract: A multifunctional meter with two pairs of input channels is disclosed. The meter has a function key disposed thereon for a user to select and set various functions. A first input channel and a second input channel are respectively formed on the meter by two sets of positive probe sockets and negative probe sockets for sequentially receiving two sets of measured values. A processing unit is disposed within the meter and connected with a display of the meter for selectively display, storage and/or calculation of the two sets of measured values. With this arrangement, convenient electrical measurement can be attained without removal of the probes and change of objects in the case of two objects to be measured.

Abstract: The invention provides a true average, wide dynamic range microwave power sensor using a diode-stack-attenuator diode stack technology. The invention provides a diode stack microwave power sensor which includes an RF signals receiver having wide dynamic power ranges; a low power sensor path connected between the receiver and ground for sensing relatively low power RF input signals. The low power sensor path includes one or more stacked RF diodes in which a number of diode pairs may be coupled to ground through respective capacitors. An impedance network including attenuating resistors R1 and R2 are connected in series between the receiver and ground. A high power sensor path is connected in parallel between the attenuating resistors R1 and R2 and ground for sensing attenuated relatively high power RF input signals.

Abstract: A circuit for use in a DMM utilizes an auxiliary A/D converter to measure the battery voltage of the DMM and displays the result on the LCD display screen of the DMM. The user receives a numeric indication of the battery voltage measured, rather than a simple good/bad or bar graph indication. The voltage measured provides the user with a quantitative indication which allows the user to determine how close the battery is to being exhausted. Thus, the user can be made aware of a weakened state of the battery before operation of a backlight further drains the battery to an unacceptably low level.

Abstract: A multicolor multi-element display system includes a plurality of multicolor display elements, each having color control inputs for controlling its color and an enable input for controlling its condition. The color control signals are commonly presented to the interconnected color control inputs of all display elements. The individual display elements are independently illuminated or extinguished by enable control signals presented to their enable inputs.

Abstract: An electronic accessory assembly to be used with a host electronic instrument provides previously recorded data from a non-volatile memory as to the accessory's operational capabilities. This memory is accessed by a host device either when the host device is powered up, or when an new accessory is connected to the host device. The host device then uses this information along with the operational requirements of the user to set the operational parameters of the accessory/host combination to optimally perform the functions required by the user.

Abstract: A simplified user interface for an electronic test and measurement device comprises an arrangement of a segmented LCD device and a plurality of keys used to implement a softkey system, in combination with a single AMPs input connector and a rotary selector having only a single position for each basic kind of parameter to be measured. The segmented LCD device includes, at each location adjacent to a key, a plurality of segments representing a vertically-arranged list of functions to be controlled. In one embodiment of the invention, the housing of the electronic test and measurement device is fabricated to have finger-like projections overlaying a portion of the LCD screen for creating the appearance of the continuation of displayed LCD softkey separation lines.

Abstract: A display system for vehicle data provides a smooth and responsive display of vehicle data even when the data is transmitted on an irregular basis by extrapolating from the previously received data when data is not received in a given interval. The invention allows display data to be preempted by higher priority data in a shared communications system.

Abstract: A tachometer has a display responsive to an rpm signal for producing an observable indication of an rpm value. A circuit responsive to an engine input develops a standard rpm signal representative of instantaneous engine rpm, and a differential Power Band amplifier circuit amplifies the difference between the standard rpm signal and an adjustable “offset” rpm signal by predetermined gain to produce an amplified differential rpm signal. A switching circuit selects the standard rpm signal or the amplified differential rpm Power Band signal for driving the display. A peak or valley rpm signal may also be developed and selected for display either in a standard mode or a differentially amplified Power Band mode.

Abstract: A measuring system performs measurement of two measured values and simultaneously exhibits the two measurement results in a digital format on a single variable color display device in respectively different colors, in order to distinguish them comfortably.

Abstract: A digital measuring device of the invention simultaneously exhibits the measured value of an analog signal, by digital indication, and its relation to an analog limit, by color of the digital indication. The measuring device includes an analog comparator, for comparing the value of the analog signal with the analog limit and for developing a comparison accordingly, and a digital measuring device, for converting the measured value of the analog signal to digital data, which are digitally exhibited on a variable color light emitting diode digital display device. The comparison signal is applied to a color control input of the display device, for controlling the color of the digital indication in accordance with the relation of the value of the analog signal to the analog limit.

Abstract: A handheld measurement device combines a logic probe, a timing analyzer, a voltmeter and a continuity detector. The measurement device provides a visual logic level indicator with an audible logic level indicator. Three channels are provided, each with simultaneous combinational triggering, to facilitate the analysis of signal timing. The device provides simultaneous measurements from a single probe.

Abstract: A voltage tester has an indicator housing and two separate probes connected to the housing by lead wires. One or more visual indicators are provided on the top surface of the indicator housing which wrap around to the sides and front of the indicator housing, and the bottom of the indicator housing has a clip into which the probe handles may be snapped from the sides of the clip so as to hold the probes beneath the indicator housing with the probe tips extending forward of the indicator housing and spaced a distance apart so as to fit into the blade openings of an ordinary wall outlet.

Abstract: A variable color digital measuring system performs sequential tests and exhibits each measured value in a color in accordance with the previous measurement errors. An error memory is provided for storing a value indicating whether there was a measurement error. A color control illuminates the present measured value in a first color when the contents of the error memory indicate that there was no previous measurement error, and in a second color when the contents of the error memory indicate that there was a previous measurement error.

Abstract: A measuring device automatically illuminates a digital indication of the measured value in a color in accordance with the selected measurement range.

Abstract: A device for non-contact, non-invasive measurement of current or power in a wire, cable or conductor includes a small coil having multiple turns and no ferromagnetic core. The coil may be secured to a wand or housing adapted to be used to place the coil in close proximity to the wire, cable or conductor, whereby a voltage is induced in the coil. An amplifier may be utilized to increase sensitivity. A readout indicates the magnitude of the induced voltage, and a scaling device renders the readout display indicative of the current or power in the wire, cable, or conductor. To measure direct current flow, the coil may be vibrated or rotated adjacent to the conductor to cause the magnetic field to induce a voltage in the coil. The readout may comprise a digital display, a series of light emitting devices, or a flashing light emitting device having a flash rate proportional to the magnitude of the voltage. The device may be constructed in a wand or pen-like fashion, with the coil incorporated into the wand.

Abstract: A variable color digital measuring instrument sequentially exhibits measured values in a color in accordance with the relation of the present measured value to a past measured value. A memory, controlled by a timer, is provided for storing data representing the past measured value. A comparator compares the present measured value with the data stored in the memory and develops a comparison signal accordingly, which is then used to control the color of the presently exhibited measured value.

Abstract: An input ranging circuit for an electronic instrument that allows for measuring a.c. voltage, d.c. voltage, and d.c. resistance is provided. The voltage ranging circuit has three modes, d.c. volts, a.c. volts, and ohms, which are selected by a mode switch. A resistor network containing an input resistor, feedback resistors, a reference resistor, and divider resistors provides resistances that are ratiometrically scaled to maintain relatively tight ratio tolerances. A switch array coupled to the resistor network provides for the selected circuit configuration and divider ratio in conjunction with the mode switch. Each of the switches in the switch array may be independently controlled via control signals. In d.c. volts mode, the input voltage is divided down according to a desired voltage divider ratio. In a.c. volts mode, the voltage divider is supplemented with an a.c. amplifier configured to extend the useful bandwidth of the input ranging circuit.

Abstract: A new Utility Meter and Display System for reading and displaying utility usage information within a building structure. The inventive device includes an encasement, a microprocessor within the encasement, a display, a keypad, and a printer within the encasement for printing selected information for the user. The microprocessor is electronically connected to a water meter, an electric meter, a gas meter and a telephone for reading the usage of the various utilities. The printer is electronically connected to the microprocessor for printing out selected screens on the display. The inventive device preferably includes a modem within for receiving billing information from the utility companies for determining the current rates.

Abstract: A self-powered electrical clamp meter measures AC voltages in the range of 6 volts to 600 volts and AC currents in the range of 1 ampere to 300 amperes, and receives operating power from the source of the voltage or current being measured. The clamp meter employs first and second rectifier circuits. One rectifier generates rectified AC power from an AC voltage signal supplied by a voltage probe, and the other rectifier generates rectified AC power from an AC current signal supplied by a current probe. First and second regulator circuits generate regulated DC power from the rectified AC power, and corresponding scaling circuits generate first and second scaled voltage signals whose respective amplitudes are proportional to the output of the corresponding rectifier. A switch selects the first scaled voltage signal when a voltage is being measured, and the second scaled voltage signal when a current is being measured.

Abstract: A device for non-contact, non-invasive measurement of current or power in a wire, cable or conductor includes a small coil having multiple turns with a thin ferromagnetic strip. The coil may be secured to a wand or housing adapted to be used to place the coil in close proximity to the wire, cable or conductor, whereby a voltage is induced in the coil. An amplifier and or an analog or digital signal processor is utilized to increase sensitivity. A readout indicates the magnitude of the induced voltage, and a scaling device renders the readout display indicative of the current or power in the wire, cable, or conductor. The readout may comprise a digital display, a series of light emitting devices, an oscilloscope, a digital computer display system, or a flashing light emitting device having a flash rate proportional to the magnitude of the voltage. The device may be constructed in a wand or pen-like fashion, with the coil and strip incorporated into the wand.

Abstract: A variable color display system exhibits a display unit in a color in accordance with the value of a limit. The color signals are developed in accordance with the value of the limit and applied to a color control input of the display system to control its color substantially continuously.

Abstract: A reading meter (10) is capable of use with a plurality of different sensor heads (16, 16b). The reading meter (12) includes a digital display (20), a processor (22) and memory (23), and an analog-to-digital converter (ADC 41). Each different sensor head includes a memory (32a) which carries at least the processing algorithm for the particular sensor. In operation, the reading meter (12) reads the detector head memory (32a), and loads the information so read into its processor memory (23). The raw sensor data is converted to digital form, and processed in accordance with the stored algorithm, to produce the desired display. In one embodiment, the detector head memory (32a) is read, and the information is serially coupled to the reading meter. In another embodiment, the serial data is converted to optical signals (634) for transmission.