2336 results about "Voltmeter" patented technology

A battery management system is disclosed for control of individual cells in a battery string. The battery management system includes a charger, a voltmeter, a selection circuit and a microprocessor. Under control of the microprocessor, the selection circuit connects each cell of the battery string to the charger and voltmeter. Information relating to battery performance is recorded and analyzed. The analysis depends upon the conditions under which the battery is operating. By monitoring the battery performance under different conditions, problems with individual cells can be determined and corrected.

Provided herein are methods and apparatus for stroke volume determination by bioimpedance from a patient's upper arm, or brachium, utilizing pulsations of the brachial artery contained therein. The apparatus includes two or more spaced apart alternating current flow electrodes positioned on the patient's arm proximate the brachial artery and two or more spaced apart voltage sensing electrodes positioned on the patient's arm proximate the brachial artery. The voltage sensing electrodes are positioned between the alternating current flow electrodes on the arm. An alternating current source is electrically connected to the alternating current flow electrodes and a voltmeter electrically is connected to the voltage sensing electrodes. A data input device is provided along with a processing unit in communication with the data input device, the alternating current source, alternating current flow electrodes, the voltmeter, and voltage sensing electrodes. The processing unit is capable of using data from the data input device and voltage sensing electrodes to calculate the stroke volume of the patient.

Abstract of the Disclosure

An electrochemical cell has two terminals. One of the terminals is connected to a pulse-width-modulated (PWM) power supply and to a voltmeter. The other terminal is connected to circuitry capable of switching between amperometric and potentiometric measurement modes. A sequence of successive approximations permits selection of a PWM duty cycle giving rise to a desired voltage at the terminal connected with the power supply. In this way a stable excitation voltage is supplied to the cell even in the face of supply voltage instability or drift or instability in electronics coupled with the cell.

Disclosed are methods and apparatus for automatically installing and/or aligning antennas of wireless bridges in computer networks. In general terms, when a particular bridge is installed or aligned, an installation mode is triggered which automatically displays an indication of one or more signal strength levels of signals received into the particular bridge. In the automatic installation mode, the particular bridge automatically searches for a remote bridge with which it can associate. After a remote bridge is associated with the particular bridge, the signal strength received by the particular bridge from the found bridge is then displayed on one or more indicators, such as light emitting diodes. Thus, one can then adjust the antenna of the bridge until an optimum power level is achieved without using any specialized equipment, such as a voltmeter or laptop for interfacing with the bridge to obtain the signal strength indication.

Frequency of judgment of welding of relays is increased to increase likelihood of early detection of welding. It is determined that a battery 22 is not being recharged or discharged when a vehicle speed V of an electric vehicle is approximately 0 and a brake pedal 54 is pressed, and a switching element of an inverter 24 is controlled to be switched to discharge electric charges which are stored in a capacitor 44. After discharging, relays 30, 32 are turned off, and voltages RV1, RV2 between the terminals of the relays 30, 32 are detected by voltmeters 40, 42 to judge whether either of the voltages RV1, RV2 has a threshold value RVref (approximate value 0) or less. When it is so determined, it is judged that the relays 30, 32 are welded, and an LED 70 is illuminated.

Enhanced voltmeter leads includes load circuitry having a test load that can be switchably coupled between the leads to help identify faults in a circuit under test. In certain embodiments, the value of the test load can be any appropriate value set according to parameters or characteristics of the circuit under test. In these embodiments, the value of the test load can be set manually or automatically or both. The types of faults that can be identified include a short-to-ground, an open circuit, and a high (e.g., corrosive) resistance. The leads include a switch whose setting is adjustable to couple and decouple the test load between the leads. The switch can be located in the leads or in a lead handle of the leads for easy access by a user/technician. The leads can also include a fuse or circuit breaker for safety reasons. The leads can be used systematically to help identify the type and location of a fault from voltage readings. The voltage readings are obtained at various points in the circuit under test with the switch both closed and open. Conventional test leads or the leads that include the switch to couple/decouple the test load can be used if the load circuitry is integrated into the voltmeter or if the load circuitry has a separate coupling or connection to the voltmeter inputs.

The invention provides a device and a method for measuring thermoelectric parameters of a film. The measuring device, which has a symmetric structure, comprises a radiating fin, a thermoelectric module, a heat insulation material, metal round rods, a thermocouple wire, a voltmeter, a power supply, a data acquisition instrument and a computer. The measuring method provided by the invention comprises the following steps of: clamping a film to be measured between two upper and lower metal round rods which are completely same while the area of the film sample is the same as the cross-sectional area of the metal round rods, controlling the ambient temperature of the measuring device and the heat flow of the film sample by the use of the thermoelectric module, detecting and recording each performance parameter of the film thermoelectric material at real time by the use of the data acquisition instrument. The invention has the following advantages: the performance of the film thermoelectric material at different temperatures can be measured, that is to say, the same device can be utilized to simultaneously measure the thermal conductivity coefficient, Seebeck coefficient and conductance coefficient of the film thermoelectric material so as to calculate ZT values of the film thermoelectric material at different temperatures. According to the invention, the measuring device has a simple principle, is convenient to operate, is small in size, has many test functions and has high measuring precision.

A voltmeter measures an unknown voltage on a target surface using multiple sampling stages or a parallel reference capacitor. A movable shutter may alternately be closed during resetting of a voltage measuring circuit and opened so as to expose a detector plate to the target surface during two sampling stages. Alternatively, the shutter may be used to modulate exposure of a detector plate to the target surface.

An apparatus for measuring a characteristic and a chip temperature of an LED includes a thermal conductive component. An LED chip is disposed on the thermal conductive component. A temperature control unit is connected to the thermal conductive component for providing a temperature to the thermal conductive component, and therefore providing the temperature to the LED chip via the thermal conductive component. A power-source and voltage-meter unit provides a current to the LED chip, and measures a voltage value of the LED chip. Under a measurement mode, the current is featured with a current waveform having a high current level and a low current level which are alternatively changed, for applying to the LED chip. Measurements are conducted respectively corresponding to the high current level and the low current level, and a correlation curve between the voltage and the temperature can be obtained with the results of measurement.

A cathodic protection system comprising remote test units for measuring various voltages and currents at remote locations on a cathodically-protected pipeline. The remote test units may comprise a processor configured to store measurements taken with the voltmeter and a wireless transceiver for communicating with other test units and/or a Web server or host computer in a daisy-chain or mesh radio configuration. The remote test units may comprise an instant-off switch which electrically connects the pipeline with a buried protected coupon of the same material as the pipeline, and a voltmeter configured to measure the instant-off potential of the protected coupon when the switch is opened. The test units may also comprise a millivoltmeter configured to measure a voltage across a critical bond current shunt resistor and an ammeter configured to measure AC and DC current flowing between the pipeline and the protected coupon with the instant-off switch is closed.

The present invention is implemented by deploying an enhanced ground fault detection and location apparatus and by using the apparatus in conjunction with specific circuit analysis methods, using the information generated by the ground fault detection and location apparatus. The ground fault detection and location apparatus comprises the functionality of a voltmeter, an ammeter, a frequency generator, and a variable power supply, thereby providing for a variety of signals and analyses to be performed on a unintentionally grounded circuit in an ungrounded AC or DC power distribution system. The apparatus includes a main unit and a remote unit, which may be a portable hand-held unit. In a first mode, the apparatus of the present invention can be used to detect ground faults. By switching to a second mode, the apparatus of the present invention can be used to locate ground faults. The methods of the present invention involve the generation of various signals by the main ground fault detection and location unit. The generated signals are introduced into the electrical distribution system and monitored by various means, including one or more remote units. By analyzing the system-level response to the generated signals, the specific location of the ground fault or faults can be more readily ascertained, thereby promoting rapid and efficient repair and recovery practices. The apparatus of the present invention may be implemented as a dedicated, permanent installation or as a temporary portable system. Additionally, the system may be implemented as an automatic computer-controlled ground fault location and detection system.

The invention discloses packaging equipment for a micro atomic gas chamber and a process technology method thereof. The equipment comprises a sample chamber, a pressure bar, a sample wafer, a sample stage, a heating wire, a temperature measurement probe, a vacuum pump connector, an inflation inlet, a direct-current high-voltage power supply, a voltmeter, a resistor, and other measurement and control devices. The method comprises: step 1, the selection of materials; step 2, the processing of the materials; step 3, the washing of the sample wafer; step 4, the bonding of a first surface; step 5, the bonding of a second surface; and step 6, the detection of a sample, and is a method which closes metal rubidium generated by adopting an in-situ chemical reaction method in a micro gas chamber. The method has the advantages that the special equipment is a common high vacuum system which is based on an anode bonding technology principle and adopts a relatively cheap mechanical pump, namely molecular pump air-bleed set; at the same time, inert gas is used to take measures such as the repeated inflation to the vacuum system to clean, the high temperature baking to the local sample wafer to remove gas and so on, to lighten the influence of residual gas and adsorbed gas as far as possible, particularly lighten the oxidation of rubidium.

An apparatus and method to detect failure of an electrolytic capacitor that smoothes a DC voltage in an inverter circuit. The apparatus detects failure of a smoothing electrolytic capacitor in a motor drive inverter circuit that rectifies and smoothes an AC voltage through a rectifier and the smoothing electrolytic capacitor and converts a rectified and smoothed DC voltage into a 3-phase voltage to drive a motor. The apparatus includes a voltage meter, a current sensing unit, and a controller. The voltage meter measures a DC voltage of an inverter when the motor is not in operation. The current sensing unit measures a phase current of the motor when the motor is not in operation. The controller estimates an ESR value of the smoothing electrolytic capacitor from the DC voltage of the inverter and the motor phase current to detect failure of the smoothing electrolytic capacitor.

A terminal assembly for measuring electrical current passing to and from a battery post, including an electrically conductive collar for connecting to a post of a battery, and an electrically conductive terminal for receiving a connector of a load. An electrically conductive resistor having a known resistance extends between outer surfaces of the collar and the terminal. The terminal assembly is incorporated into a battery, which also includes a volt meter connected between the outer surfaces of the collar and the terminal for measuring the voltage drop across the resistor, memory for storing the known resistance of the resistor, and a processor programmed to receive the measured voltage drop from the volt meter, retrieve the known resistance from the memory, and calculate current flow through the resistor based on the measured voltage drop and the known resistance, whereby current flow to and from the battery can be measured.

The resistance measuring method and device is especially suitable for quickly measuring small resistance and varying resistance according with Ohmí»s law. The resistance measuring device includes constant-current pulse source, four-end network containing the measured resistance, high input impedance amplifier, real-time measuring and automatic recording display circuit for voltmeter, and digital millivoltmeter. It measures resistance through generating constant-current pulse, producing voltage drop on the measured resistance, amplifying the voltage drop, automatic conversion between reading state and holding memory state and recording and displaying voltage drop. During measuring resistance change, given voltage synchronous with the constant-current pulse is added into the four-end network, and the varying voltage drop the constant-current pulse produces on the measured resistance is measured by means of potential approaching method and further differential method.

The invention provides a calibration system of a digital quantity input type electric energy meter. The problem of calibration of a novel digital quantity input type electric energy meter is solved. The calibration system of the digital quantity input type electric energy meter comprises an analog power source, high-accuracy PT and CT, a high-accuracy digital voltmeter, an A/D sampling module, a protocol generation module, a management module, an analog standard meter, an electric energy meter to be measured, an error counter and a control computer; the control computer controls the analog power source to output an analog voltage and current signal, and one path of the analog signal is measured by the analog standard meter and used for calculating the error of the meter to be measured; after the other path is converted by the high-accuracy PT and CT and processed by the AD sampling module and the protocol generation module, measurement data which conform to IEC61850 standard are generated and transmitted to the meter to be measured by an optical fiber or a twisted-pair, the meter to be measured receives and analyzes a data frame, the electric quantity is calculated, and the pulse of the electric quantity is output and used for calculating the error of the analog standard meter. The invention can calibrate an indoor digital quantity input type multi-functional electric energy meter which conforms to the protocols of DL/T860-9-1/2 and IEC61850-9-1/2LE, and a calibration result can trace to a national standard.

A direct-current to direct-current conversion (DC/DC) apparatus includes a control circuit having an error amplifier for voltage control and controlling a direct-current to direct-current conversion based on a pulse width modulation control using an output of the error amplifier. The error amplifier inputs a voltage signal corresponding to an output voltage of a DC/DC result and a plurality of reference voltage signals. The DC/DC apparatus also includes a soft start capacitor to provide one of the plurality of reference voltage signals. The error amplifier amplifies a difference between the voltage signal corresponding to the output voltage of a DC/DC result and a voltage signal of a lower potential among the plurality of reference voltage signals and, based on the amplified output, carries out the pulse width modulation control. Furthermore, the control circuit includes a circuit for discharging charges corresponding to the output voltage of the DC/DC result when a power supply to the control circuit is turned off. By the constitution, it is possible to easily realize power turn-on/turn-off sequence controls without requiring any special logic circuit, and thus to control rise/fall characteristics of the output voltage without depending on the load.

Two current electrodes 2 and 3 are arranged on a circumference of a subject 1, a distance between the two current electrodes being sufficiently shorter than a circumferential length of the subject 1. A current source 4 passes a current between the two current electrodes. A measuring electrode 5 is arranged adjacent to one of the two current electrodes 2 and 3. A measuring electrode 11 is arranged substantially opposite to the two current electrodes 2 and 3 across the subject 1. A voltmeter 7 measures a voltage generated between the measuring electrodes 5 and 11. A body fat computing unit 25 computes the quantity of subcutaneous fat 8 of the subject 1 according to the voltage measured with the voltmeter 7.