107 results about "Ohm's law" patented technology

A fuse array having a plurality of fusible links that can be addressed by two electrodes is disclosed. The fuse array includes two conductive strips having the plurality of fusible links located therebetween and electrically coupled to the conductive strips. The fusible links have different electrical resistance and each fusible link includes a fuse portion. A voltage potential applied across the conductive strips induces current flow through the fusible links in accordance with Ohm's law and ohmic heating occurs at the fuse portion in proportion to the square of the current. The voltage is increased to cause sufficient ohmic heating to occur in the most conductive fusible link (the fusible link having the lowest electrical resistance) so that the fuse portion in that fusible link fuses. Because the fusible links are connected in parallel to the conductive strips, an equivalent resistance of the plurality of fusible links increases and the current flow diminishes so that no further fuse portions are fused at the selected voltage level. Thereafter, the voltage level may be increased to fuse the most conductive fusible link remaining that is not fused. The fuse array may be incorporated into a circuit as a resistor that can be tuned to circuit requirements or as a physical structure in MEMS devices wherein the fuse array may be tuned to change physical properties of the MEMS device.

A permanently mounted AC powered control/display unit and a remote sensor for use in measuring ground resistance. The sensor is permanently mounted around the earth grounding cable. The control display unit generates a 1953 Hz, 5 Vac sine wave which is sent via a cable to a 100:1 ratio drive transformer in the remote sensor. The transformer induces a 0.05 Vac sine wave in the ground cable. The resulting current is detected by a 100:1 turns ratio sense transformer. The current is returned via the cable to the control display unit and converted to a voltage, filtered, amplified and rectified by a synchronous rectifier. The rectified voltage is again filtered and presented to an analog to digital converter. A microprocessor reads the output of the analog to digital converter and the ground resistance is computed by using Ohm's Law (R=E/I), the result being shown on a display.

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.

A combiner that calculates energy produced by each panel feed during the daytime, and calculates a resistance value needed to calculate the energy by injecting a known current into each panel feed at nighttime and measuring the resulting voltage across a resistive element in each panel feed. A voltage tap across the protection device in each panel feed allows logic and control circuitry to measure the voltage across each protection device. At nighttime, a known current is injected into each panel feed and the voltage across each protection device is measured. Plugging the current and voltage into Ohm's Law, a resistance of each protection device is calculated, then that resistance value is used during the daytime to calculate energy produced by each string in real time and to monitor each string's performance. When an individual string's performance wanes, an alarm is indicated to help the operator troubleshoot which individual panel(s) within the string is responsible for that string's underperformance.

An electronic device simulator includes a three-dimensional lumped device model, a three-dimensional visco-elastic process simulation model and a material design model that are interlinked with each other. The three-dimensional lumped device element model comprises a Poisson's equation model, an electron continuity equation model, a hole continuity equation model, a Maxwell's equations model, an eddy current equation model, and an Ohm's law equation model. The simulator accounts for the three dimensional characteristics of the circuit to determine circuit performance.

An online inspection system for internal resistances of batteries comprises a power supply module, a voltage inspection control module, an internal resistance inspection control module, a constant-current discharge module, an automatic gain control high-precision differential acquisition module, a microprocessor module, an abnormality detection module and a communication module. The power supply module provides a variety of power supplies for a complete machine and provides isolated power supplies for the constant-current discharge module, the high-precision differential acquisition module and the communication module. First, low-current constant-current discharge is carried out on a battery and is stopped after a certain period of time; then, variation of voltage of the battery by taking a specified time interval as a unit time in the whole process and voltage variation in a certain period of time after discharge are recorded; next, the value V of the voltage is calculated through a mathematical model by carrying out trend analysis on variation of the voltage with the time and subdividing the data; and finally, the internal resistance of a monomer battery is calculated by using the Ohm's law according to the V and a discharge current I.

The invention provides a technical scheme of a power distribution system equivalent ground distributed capacitor measuring method, comprising the following steps: 1) injecting signal current with constant frequency into a power distribution system; 2) measuring neutral current of primary side of an arc suppression coil and busbar voltage of a busbar in the power distribution system, filtering the measured neutral current and busbar voltage, and filtering out power frequency quality to obtain current injected into the power distribution system and pressure drop generated by the current on an equivalent ground distributed capacitor; 3) modeling the power distribution system based on a lumped parameter model, and calculating a complex functional equation of the injected signal current, voltage and power distribution system equivalent ground distributed capacitance according to Ohm's law; and 4) calculating equivalent ground distributed capacitance value of the power distribution system and ground insulation resistance value of the power distribution system according to the equation in the step 3). The method provided by the invention is clear in principle, is easy to implement, and has a wide application range and high accuracy in computation.

This is a measuring method of the conducting-ring constriction resistance adopting the triple-ring which belongs to the field of electric test-statistics. Its characters lie in grouping three conducting rings and making the three wire leads of the conducting-ring rotating part short circuit. The two fixed wire leads are connected separately to the steady current signal adopting the voltage-measuring device to measure the voltage between the other wire lead and the signal-injected optional wire lead. According to the ohm's law, it can workout the constriction resistance value range of the conducting ring by the measured voltage range and the injected current value.

A leakage current detection method and device. The method is used to detect a leakage current of an on-board device on a PCBA board, and comprises: providing a fixed voltage for the leakage current input end of an on-board device under detection, and connecting the leakage current output end of the on-board device under detection to the inverting input end of an operational amplifier of a resistance test module, the resistance test module comprising the operational amplifier and a reference resistor which is connected between the inverting input end of the operational amplifier and the leakage current output end; detecting an output voltage of the resistance test module; and based on Ohm's law, according to the output voltage and reference resistance, calculating a leakage current flowing through the on-board device under detection. The on-board device under detection is connected to the resistance test module, and a certain voltage is applied thereto, so that the leakage current of the on-board device on the PCBA board can be calculated according to the reference resistance of the resistance test module and the output voltage of the operational amplifier. The batch detection can be achieved without removing the on-board device from a single board, so that the detection accuracy is high, the detection efficiency is high, and the detection ratio is large.

The invention discloses short-distance measurement method and structure of the grounding resistance of a grounding network. A current pole used for measuring the grounding resistance of the grounding network is arranged near the grounding network to be measured, even inside the grounding network; the current pole is used as a small grounding network to be measured, and the grounding resistance R pole of the current pole is measured by the traditional long-distance measuring method; finally, a test voltage is applied between the grounding networking to be measured and the current electrode, a test current between the grounding network to be measured and the current pole is measured by an ampere meter, and the total grounding resistance R (total) of the grounding network to be measured and the current pole is calculated by using the Ohm's law; and the grounding resistance R pole of the current pole is subtracted from the R (total) to obtain the grounding resistance R (network) of the grounding network to be measured. The invention not only can avoid the problems of long wire pay-off distance, large work load, easy interference production and the like, but also can avoid the technical difficulty that the measurement precision of the traditional short-distance measurement method can not satisfy actual requirements.

Maximum HF current is initially introduced into tissue at a pre-specified maximum coagulation voltage. In this initial state, the tissue behaves in accordance with Ohm's law and can take up the maximum energy per unit of time. After the tissue has changed from an initial state to a state in which the tissue impedance or resistance is voltage-dependent, the HF parameters are selected such that the maximum possible energy input per unit of time is set.

The embodiment of the invention discloses a salinity detection method which comprises the following steps: putting two parallel polar plates into a tested solution, applying a certain electric potential to two ends of the polar plates, and measuring the current flowing through the polar plates; calculating the conductivity (G) of the tested solution according to an Ohm's law; calculating the unit conductivity: the conductivity (G)*cell constant (L/A), wherein L refers to the liquid column length between the two polar plates, and A refers to the area of the polar plates; taking two golden fingers arranged on the gold plated surface of brass in parallel as probes, converting the change of resistance into change of output voltage by virtue of a bridge according to different conductivities, or adopting a series resistance voltage division method, filtering, amplifying, compensating, rectifying, amplifying, feeding into an A/D conversion chip, and finally reading the data by virtue of a singlechip system. According to the salinity detection method and the salinity meter thereof provided by the invention, the calculated salinity value is accurate and fixed.

Disclosed herein is a chemistry and physics calculator for helping a user to solve chemistry and physics problems. The calculator does more than calculating numbers or solving equations; rather, the calculator includes an adaptable menu and sub-menu system that helps a user analyze a problem, determine the type of the problem, and helps a user choose equations that are needed to solve the problem. The calculator includes at least some of these topics: balancing equations, stoichiometry, gas laws, equilibrium, dimension analysis, electrochemistry, electricity, Newton laws, thermodynamics, properties of matter, mirrors and lenses, Ohm's law, and Kirchhoff's Law. Additionally, the calculator prompts users to input units for variables, performs unit analysis, and displays results with units. The invention can be implemented as a handheld calculator, as a computer program, or as a program for a handheld device such as a smart phone.

The invention belongs to the technical field of electrical measurement and relates to a LABview-based method for measuring temperature-resistivity. The method is characterized by utilizing a T-shaped thermocouple to acquire the temperature of the environment which the resistance material sample to be tested is in and utilizing a voltage value acquisition board to convert the analog signals of the voltage values to digital signals according to the formula and transmit the digital signals to an electronic computer; in the step of current change and output, transmitting the initial current value input into the computer when testing starts or the current value changed after voltage judgment to a current source via a program so that the current source outputs the transmitted current value; in the step of voltage acquisition and judgment, utilizing a digital multimeter to acquire the voltage values of the two ends of the resistance material sample to be tested; and utilizing Ohm's law R=U/I to obtain the resistance and then computing the resistivity according to the formula rho=R*S/L and automatically inputting the measured information and data into the computer and processing and storing the measured information and data. The method has the advantages of accuracy in measurement, intuitive data analysis, simplicity in operation, time conservation, intuitive result display and low cost.

The invention relates to a method for monitoring hole depth in the drilling process of a cable drill pipe, which is characterized in that in the method, the drill pipe is designed based on a central cable type large-through-hole drill pipe, one end of each drill-pipe cable is connected to a high-precision resistor with the same resistance, the bottommost drill-pipe cable is connected with a signal emission terminal powered by a direct-current level; a signal ground is connected with a lower drill pipe by a probe bracket, and then is connected with a ground resistor to form a closed loop; the electric potentials of the two ends of the ground resistor are acquired by using an acquisition card, then the current of the whole loop is calculated according to the Ohm's law; the value of electric potential of the upper end of a cable is subtracted from the value of level of an emitted signal to obtain the value of voltage withstood by an integral drill pipe, then the obtained value of voltage is divided by the value of current of the loop so as to obtain the total resistance of a series resistor in the integral drill pipe, the total resistance is divided by the resistance of a resistor in each drill pipe so as to obtain the number of the drill pipes in a hole, and through multiplying the number of the drill pipes by the length of each drill pipe, adding the obtained value and the length of a fixed drilling tool below the hole, and subtracting an allowance of the drill pipe from the obtained value, the calculated maximum value is the hole depth. By using the method disclosed by the invention, the hole depth can be monitored in real time without manual correction.

The invention provides an environment pore pressure static sounding probe for in-situ detection of heavy metal polluting components and concentration. Measurement of the heavy metal polluting components and the concentration is finished by an X-ray energy spectrum analysis device and a resistivity testing device. The X-ray energy spectrum analysis device comprises an X-ray emitter, an X-ray detector and a high-performance filter. The heavy metal polluting components in soil are detected through X-ray detection and analysis. The resistivity testing device consists of four annular electrodes at the periphery, wherein the annular electrodes are isolated by an insulating layer; the two middle annular electrodes are testing electrodes; the upper and lower annular electrodes are emitting electrodes; the emitting electrodes are used for emitting current to the soil body; the testing electrodes are used for measuring potential difference; the resistivity of the soil body surrounding the electrodes can be calculated by combining an Ohm's law and the pollution concentration is calculated through a specific heavy metal element concentration and resistivity conversion formula. The environment pore pressure static sounding probe provides a powerful identification tool for heavy metal polluted foundation soil in-situ evaluation in environmental geotechnical engineering.

The invention discloses an aluminium electrolysis bus system resistance to ground detection device and a detection method thereof. The device comprises a keyboard input device, a partial pressure filter, an amplifier, an MCU controller and an LED display; wherein all the parts are mutually electrically connected. The detection method includes 'auxiliary short circuit line method' and 'auxiliary grounding method'. The 'auxiliary short circuit line method' includes that the aluminium electrolysis cell bus system resistance to ground detection device is connected with a thick copper wire, short time short circuit to ground of the copper wire at electrolysis cell buses at different voltage classes is utilized to measure leakage current, a short circuit point is disconnected to measure the voltage to ground of the point, and equivalent resistance to ground of system is calculated according to ohm's law; and the 'auxiliary grounding method' includes that the whole series electrolysis cell support and bus piers are measured one by one, and disqualified point is found and cleaned, so as to judge and process an insulation breakdown point. The detection device and method thereof also can be applied to other occasions with strong direct current magnetic field and high distributed capacitance.

The present invention provides methods and apparatus for determining a dynamical property of the systemic or pulmonary arterial tree using long time scale information, i.e., information obtained from measurements over time scales greater than a single cardiac cycle. In one aspect, the invention provides a method and apparatus for monitoring cardiac output (CO) from a single blood pressure signal measurement obtained at any site in the systemic or pulmonary arterial tree or from any related measurement including, for example, fingertip photoplethysmography.

According to the method the time constant of the arterial tree, defined to be the product of the total peripheral resistance (TPR) and the nearly constant arterial compliance, is determined by analyzing the long time scale variations (greater than a single cardiac cycle) in any of these blood pressure signals. Then, according to Ohm's law, a value proportional to CO may be determined from the ratio of the blood pressure signal to the estimated time constant. The proportional CO values derived from this method may be calibrated to absolute CO, if desired, with a single, absolute measure of CO (e.g., thermodilution). The present invention may be applied to invasive radial arterial blood pressure or pulmonary arterial blood pressure signals which are routinely measured in intensive care units and surgical suites or to noninvasively measured peripheral arterial blood pressure signals or related noninvasively measured signals in order to facilitate the clinical monitoring of CO as well as TPR.

The invention discloses an underground structure construction-oriented soil performance monitoring device and a working method thereof. Corresponding laser transmitters and receivers are arranged on the outer walls of circuit protection boxes and the inner walls of soil pressure contact plates, and circuits in each circuit protection box are connected in parallel and turned on after two metal conductive rods are conductive in water. Disturbance of soil is reflected by monitoring the displacement of the soil pressure contact plates via a laser ranging technology, and accurate measurement on multi-directional deformation of soil is realized; meanwhile, the pressure change value of the soil in each direction is calculated via the displacement measured by laser ranging with the use of Hooke's law; besides, the change of underground water level can be displayed via the change of main circuit trunk current by using the Ohm's law; multi-depth and multi-directional automation degree test on the soil is realized, the monitoring data is reliable, the safety of underground structure construction and surrounding buildings is ensured, and the device has broad engineering application prospect and will produce remarkable social and economical benefits.

The invention discloses a detection device for circuit breakage and short circuit of a secondary coil of an electric leakage mutual inductor. The detection device comprises a residual current signal detection module, an operational amplifier module and a main control module, wherein the residual current signal detection module is used for detecting the operational amplifier module; the operational amplifier module is connected with the main control module; a sampling resistor in the residual current signal detection module is adopted to sample a present value of a direct-current voltage component according to the Ohm's law; the operational amplifier module is used for amplifying the direct-current voltage component; the main control module is used for judging the present state of the secondary coil of the leaking mutual inductor by calculating the amplified value of the direct-current voltage component; the sampling resistor in the residual current signal detection module is used for converting present alternative-current of the leaking mutual inductor into an alternative-current voltage component; the operational amplifier module is used for amplifying the alternative-current component; the main control module is used for calculating an external residual current value according to the alternative-current component and the resistance of the sampling resistor R1. By adopting the detection device, the circuit breakage and short circuit faults of the secondary coil of the leaking mutual inductor can be easily and effectively detected, and the external residual current value can be normally measured.

The invention provides a ground state detection unit, a grounding device and a ground state detection method. The ground state detection unit is connected with the two sides of the grounding device. The ground state detection unit comprises a signal current source, a standard resistor and a signal detection circuit. The signal current source is connected with the standard resistor in series. A first detection point is arranged between the signal current source and the grounding switch. A second detection point is arranged between the signal current source and the standard resistor. A third detection point is arranged between the standard resistor and the grounding switch. The signal detection circuit is respectively and electrically connected with the first detecting point, the second detection point and the third detection point so as to measure the voltage among the detection points. According to the technical scheme of the invention, based on the ohm 's law, the grounding state of a contact network can be judged according to the contact resistance of the grounding switch when being switched on. Compared with the existing detection means, the operation is more direct and more reliable.

The invention provides a total voltage detection circuit and method of a high-voltage battery system. The circuit comprises an anode and cathode of the system, the ground, the detection resistor network and a high voltage switch. The detection resistor network comprises first to eight resistors, the resistance of each resistor is known, and the high voltage switch comprises a switch Kp and a switch Kn. Voltage are sampled from different electric loops formed by different serial/parallel connection manners to obtain voltage values of the different resistors, a voltage ratio alpha parameter generated by low-resistance high-precision resistors is used to correct a voltage ratio beta generated by the high-resistance low-precision resistors, an Ohm law is combined to calculate the total voltagevalue, the method is simple in operation and easy to realize, the total voltage value of higher precision can be obtained in any environmental condition, and the insulation performance of the batterymanagement system can be ensured.

The invention, which belongs to the technical field of battery management, relates to a lithium battery parameter identification method based on a composite working condition. The composite working condition is formed by N groups of cycles. Each cycle group includes a rapidly changing charge and discharge stage, a constant-current discharge stage, and a standing stage. At the standing stage of anycycle, tau2 is estimated according to a relationship between a battery terminal voltage and time; at the constant-current discharge stage of any cycle, the sum of three internal resistors R0, R1, andR3 is calculated based on the Ohm's law; for the first cycle by starting with SOC being equal to 100%, next cycle parameters R2 and C2 are used for replacement to avoid introduction of too many errors; and corresponding groups of battery model data are identified by the N cycle groups and a full-SOC-range battery model is constructed based on a table looking + linear interpolation method. According to the total capacity, the SOC corresponding to the battery after each constant-current discharge condition is calculated, open-circuit voltages under all SOCs are recorded, and a complete SOC-OCVcurve is obtained by fitting. The lithium battery parameter identification method has the following advantages: the parameter identification under different working conditions is considered fully; andthe robustness is high.

The invention relates to an analytical model method for the current conversion ratio and the phase difference of an open-type current transformer. The analytical model method comprises the following steps of: (1) establishing the principle model of the open-type current transformer; (2) deriving the magnetic path time-domain equation of the open-type current transformer according to an ohm law for magnetic path, calculating a circuit time-domain equation considering a secondary side load according to a Faraday law of electromagnetic induction and the ohm law, obtaining the actual current conversion ratio and phase difference calculation formulas of the primary side and the secondary side of the open-type current transformer by the magnetic path and circuit time-domain equations, so as to complete an analytical model for the current conversion ratio and the phase difference of the open-type current transformer. The analytical model established by the method disclosed by the invention has an important theoretical direction value on realization for compatibility between the current transformer for measurement and a current transformer for protection, and is capable of providing a theoretical basis for the error compensation of a split core type current transformer used for online calibration for an electric energy meter.