587 results about "Voltmeter" patented technology

Various embodiments of the teachings herein include a device comprising: a communication apparatus for sending and / or receiving data via a data transmission bus and a device-side connection apparatus connecting the device to the bus. The connection apparatus includes electrical contacts to be connected in pairs to bus-side electrical contacts of a connection apparatus on the bus. The contacts comprise a data contact for a data signal, a supply contact to transmit a first supply potential, a second supply contact to transmit a second potential different from the first, and a third contact. A voltmeter measures a potential present at the third contact with respect to the first supply potential and / or the second supply potential. The communication apparatus assigns an address to the device for sending and / or receiving the data via the bus, selected from multiple different predefined addresses on the basis of the potential measured at the third contact.

The invention provides an electrical performance calibration device and method for fusing electrolytic hydrogen production and a hydrogen fuel cell. The electrical performance calibration device comprises an upper computer, a first digital sampling voltmeter, a second digital sampling voltmeter, a synchronous data acquisition card, a synchronous inspection switch, a current converter, a voltage converter, an electric pile, a programmable power supply, a self-calibration module and an external calibration signal source, the synchronous inspection switch is used for detecting a single-cell voltage bus of a galvanic pile and feeding back the single-cell voltage bus to a sampling end of the first digital sampling voltmeter, and a feedback end of the first digital sampling voltmeter is connected with a first input end of the upper computer; the current converter is used for detecting a current loop of the galvanic pile; the voltage converter is used for detecting the total voltage of the electric pile; and the programmable power supply is connected with a power supply terminal of the electric pile. According to the invention, the problems of poor synchronism, lack of self-calibration, low impedance measurement precision and incompatibility of two-way metering during electrical performance calibration of electrolytic hydrogen production and hydrogen fuel cells are solved.

A voltage meter includes a sampler, a gain circuit, an accumulator and a feedback circuit. The sampler samples an input signal to generate a series of first signals and a series of second signals. The gain circuit, coupled to the sampler, modifies at least one of the series of first signals and the series of second signals, to generate a series of modified first signals and a series of modified second signals. The accumulator, coupled to the gain circuit, accumulates an operational result of the series of modified first signals and the series of modified second signals, to generate an accumulation result. The feedback circuit, coupled between the accumulator and the sampler, sends a feedback signal back to the sampler according to the accumulation result.

The utility model relates to the technical field of relay verification, in particular to a portable time relay verification circuit and device. Comprising a timer, a first intermediate relay, a second intermediate relay, a first selection switch, a second selection switch, a third selection switch, a direct current voltmeter, a power switch, a start button, a reset button, a power indicating lamp and a power module. According to the utility model, through different combinations of the three selection switches, verification of eight different types of time relays is realized by using the two intermediate relays, the structure is simple, the integration is good, the cost is low, and the verification capability of the time relay during the ship navigation period is improved.

The invention provides a display device and a display method. The display device comprises a display panel and a driving chip, the driving chip comprises a voltage regulating unit, an overvoltage driving unit and a triggering unit; the trigger unit is used for detecting whether the current display picture of the display panel is a heavy-load picture or not, and when the display picture is the heavy-load picture, the trigger voltage regulation unit and the overvoltage driving unit are triggered to work cooperatively; the voltage adjusting unit is used for adjusting a target driving voltage corresponding to a target gray scale in the liquid crystal driving voltmeter, so that the lighting effect reaches the preset brightness when the display panel displays a white picture; the overvoltage driving unit is used for starting a driving function, adjusting the parameter configuration table and performing overvoltage driving on a data line of the display panel based on the parameter configuration table and the target driving voltage so as to improve the charging rate of the heavy-load picture, so that the charging rate is improved by detecting the heavy-load picture and cooperatively adjusting the voltage and overvoltage driving, and the charging efficiency is improved. The method has the advantages of improving the charging rate of a heavy-load picture, eliminating display defects and improving the display quality.

The invention relates to the field of data processing, in particular to a remote detection method and system for an electric energy meter, and the method comprises the steps: obtaining the operation data of the electric energy meter, carrying out the window division of the operation data according to a time sequence through a variational mode decomposition algorithm, obtaining a comprehensive frequency distribution curve of the operation data in a window, and generating a time-frequency diagram; the method comprises the steps of performing peak point detection based on a time-frequency diagram, determining a main frequency peak point and an interference peak point, calculating a harmonic interference degree value of the frequency of electric energy meter data based on distribution characteristics between the main frequency peak point and the interference peak point, and using change consistency and frequency amplitude of the interference degree value to calculate an abnormal degree value of an intelligent voltmeter. And the abnormal condition of the electric energy meter is judged. According to the method, the change consistency of data of different dimensions is calculated, so that single-dimension noise interference is suppressed, and the reliability of abnormal criteria is improved.

The invention belongs to the technical field of high-temperature superconducting detection, and discloses a quench detection sensor based on a high-temperature superconducting material and a detection method.The quench detection sensor comprises an inner layer structure composed of a metal base band, a first insulating layer and a high-temperature superconducting material layer, and a second insulating layer arranged between the metal base band and the high-temperature superconducting material layer; the second insulating layer covers the areas, not at the two ends, of the outer side of the inner layer structure, and a metal base band or a high-temperature superconducting material layer is arranged between the second insulating layer and the first insulating layer; the two ends of the short-circuit connection metal are fixedly connected to the first end of the metal base band and the first end of the high-temperature superconducting material layer respectively; the number of the connecting terminals is two, the two connecting terminals are jointly used for being connected with a detection voltmeter and a detection current source through wires, and the two connecting terminals are fixedly connected to the second end of the metal base band and the second end of the high-temperature superconducting material layer respectively. The quench detection sensor is high in detection reliability.

The invention discloses a welding platform for manufacturing a lithium battery pack, and belongs to the technical field of lithium battery welding, the welding platform comprises an operation table for placing a battery pack and two bidirectional guide rails for adjusting and collecting a flat cable and a protection plate, a positioning seat is arranged on the operation table, and a positioning assembly for positioning the battery pack is arranged on the positioning seat. Through the arrangement of the voltage measuring assembly and the voltmeter, voltage measurement of all contacts of the flat cable after welding can be rapidly completed by using one-by-one descending and ascending of the voltage measuring telescopic guide rod, compared with one-by-one measurement of small-interval contacts of the flat cable with a touch pen at present, the measurement is more efficient and accurate, it is guaranteed that the voltage of the flat cable after welding is normal, and the accuracy of welding is improved. And meanwhile, through the arrangement of the retarding electromagnetic plate and the welding isolation seat, a controllable magnetic field of the retarding electromagnetic plate can be utilized to generate dynamic damping force, and magnetic-gas double-field stable control is formed in combination with airflow adsorption, so that the swing amplitude of the welding copper ring of the lightweight collection flat cable is greatly reduced, and the problem of winding of fine-pitch copper wires is effectively solved.

The invention relates to the technical field of failure evaluation, and discloses a TSV-RDL wafer level package electro-failure reliability evaluation system, which comprises an upper computer, a precision power supply, an editable controller, a direct current voltmeter and a relay array, the upper computer is connected with the precise power supply, the programmable controller and the direct-current voltmeter through a communication bus; the programmable controller is connected with the direct-current voltmeter and the relay array, the programmable controller responds to a control instruction and controls the on-off state of a current path at the connecting end of the TSV sample through the relay array, and the TSV sample receives current and voltage and responds to the current and the voltage in real time; the direct current voltmeter is used for measuring the voltage change of the TSV sample; the programmable controller judges whether a set condition is met or not based on data fed back by the direct-current voltmeter in real time, and then the on-off state of the relay is controlled. According to the invention, the current-voltage-resistance characteristics of the TSV sample can be comprehensively recorded, and the automation level of the test is improved, so that the requirements of the TSV electromigration failure test are met.

The utility model relates to the technical field of underground water level measuring devices, and discloses an underground water level ruler suitable for various wellhead conditions, which comprises a support main body, a control panel is mounted on one side of the support main body, and a switch, an indicator light, a voltmeter, a buzzer, a battery compartment and a handle are arranged on one side of the control panel. According to the underground water level gauge suitable for various wellhead conditions, the limiting rod is pulled to move outwards until the limiting rod is separated from the interior of the limiting hole, fixing of the connecting ring is relieved, balance weight devices of different shapes can be selected and used according to the field wellhead conditions, and even if the water level gauge body is clamped in field measurement, the water level gauge body can be conveniently used. When the bearing threshold value of the connecting ring is exceeded, the water gauge main body can also be pulled out, the water gauge main body is a steel bendable ruler, water level measurement work can be continued by replacing a proper balancing weight on site, the field actual working efficiency is effectively improved, and the working cost is reduced.

The invention discloses a ring main unit with a moisture-proof mechanism. The ring main unit comprises a base, a side plate, a panel, a heat conduction cover plate, a drying assembly, a heat dissipation assembly, a heat dissipation opening, a display screen, a voltmeter, an ampere meter, an observation window and a circuit breaker. The other end of the ventilation pipe is fixedly connected with a second fan, and the inner wall of the ventilation pipe is fixedly connected with active microporous silica gel; a rotary drying and dehumidifying structure is designed, when air containing moisture passes through active microporous silica gel, the active microporous silica gel can rapidly capture and adsorb water molecules in the air due to the strong adsorption capacity, the air subjected to adsorption treatment becomes dry and enters the ring main unit, an ideal operation environment is provided for equipment, and the service life of the ring main unit is prolonged. Meanwhile, in order to maintain the continuous and efficient operation of the dehumidification structure, the drying part can alternately enter a regeneration area, the active microporous silica gel is heated through the heating structure, water molecules adsorbed on the silica gel are heated and evaporated, and then regeneration of the silica gel is achieved.

The invention relates to the technical field of electric leakage protection devices, in particular to an electric leakage protection device and method for a low-voltage power distribution cabinet, and the device comprises a power distribution cabinet structure, a display screen, a voltmeter, a control cabinet, a first control machine seat, a second control machine seat, and a first insulation protection frame. A display screen and a voltmeter are installed on the control cabinet and used for displaying the state of the power distribution cabinet structure, the control cabinet is further provided with a first control machine base and a second control machine base which are used for automatic monitoring processing of the power distribution cabinet structure, and the rear end of the power distribution cabinet structure is electrically connected with a disconnection processing structure. The disconnection processing structure conducts current and actively disconnects a circuit at the same time, and a first insulation protection frame and a second insulation protection frame are arranged on the disconnection processing structure and cover the disconnection processing structure in an insulation mode. Through the arrangement of the structure, leakage protection work is facilitated.

An insulation monitor for a high-voltage onboard electrical system of a motor vehicle is provided. A respective Y-capacitor is arranged between the positive potential and the vehicle earth and between the negative potential and the vehicle earth. The insulation monitor has a current or voltage source, a voltmeter for measuring at least one of the potentials, and is configured to apply a negative current by the current source when the potential measured by the voltmeter exceeds a predefined upper value and to apply a positive current by the current source when the potential measured by the voltmeter falls below a predefined lower value. The current thus being limited to a maximum permissible contact current in the case of an insulation fault and it is possible to infer the magnitude of the insulation resistances using the voltage measured by the voltmeter and the recharging current that has been fed in.

The utility model provides an energy storage confluence cabinet and an energy storage system, and the energy storage confluence cabinet comprises a cabinet body; the primary side loop is arranged in the cabinet body, the first end of the primary side loop is connected with the charging and discharging end of the battery, and the second end of the primary side loop is connected with the direct current end of the energy storage converter; and the detection device comprises a direct current voltmeter, the detection end of the direct current voltmeter is connected with the second end of the primary side loop, and the direct current voltmeter is arranged on the outer surface of the cabinet body. In the energy storage confluence cabinet and the energy storage system disclosed by the invention, the direct current voltmeter can read the voltage of the primary side loop and visually display the voltage on the outer surface of the cabinet body, so that the operation of frequently opening the cabinet body by an operator due to voltage detection is omitted, the efficiency of monitoring the voltage of the primary side loop is effectively improved, and the cost is reduced. And the electric shock risk of operators is reduced, so that the safety of primary side loop voltage monitoring is effectively improved.

The invention provides a method, device and equipment for determining the position of an electric leakage cell in a battery pack, and the method comprises the steps: measuring the total voltage of the battery pack as a first voltage value through a first voltmeter and a second voltmeter which are connected in series; two probes of a first voltmeter are respectively connected with the total positive electrode of the battery pack and the shell of the battery pack to obtain a second voltage value, and two probes of a second voltmeter are respectively connected with the total negative electrode of the battery pack and the shell of the battery pack to obtain a third voltage value; if an absolute value of a difference value between half of the first voltage value and the second voltage value is greater than a first preset value, performing ratio calculation on the second voltage value and a rated voltage value of a single battery cell in the battery pack to obtain a first ratio, and determining the position of the electric leakage battery cell in the battery pack according to the first ratio; according to the invention, the position of the electric leakage cell in the battery pack can be determined.

A neuromorphic device includes a plurality of resistor lines, each comprising a plurality of resistors that are serially connected to each other; one or more current sources configured to control a current flowing in each of the resistor lines to a respective current value; a plurality of capacitors configured to be electrically connected to each of the resistor lines and to sample respective voltage of each of the resistor lines representing results of neuromorphic operations; and a switch configured to connect the plurality of the capacitors in parallel after the sampling the respective voltage of each of the resistor lines, to output a sum of the results of neuromorphic operations.

The invention discloses new energy automobile charging safety inspection metering calibration equipment and a control method thereof. The equipment comprises a direct current charging metering calibration module, an insulation resistance calibration module and a potential equalization calibration module, the DC charging metering calibration module comprises a DC charging gun base, a BMS simulator, a high-precision ammeter and a high-precision voltmeter. The insulation resistance calibration module comprises a main control unit, a high-precision resistor, a high-voltage switching unit and an alternating-current charging gun base, the potential equalization calibration module comprises a high-precision galvanometer, a high-precision voltage source and a low-voltage switching unit, and the low-voltage switching unit comprises a low-voltage relay set, a first banana head interface and a second banana head interface. The AC charging gun base is connected to the calibration circuit through the low-voltage relay group. By integrating the high-precision measurement module, the resistance switching unit and the BMS simulator, one-key calibration of direct-current charging, insulation resistance and potential equalization is realized, and the problems of contact resistance interference and multi-instrument collaboration are solved.

The utility model discloses a fountain waterscape control and protection device, which relates to the technical field of fountain waterscape, and comprises a waterscape pool and a fountain machine pump set, the fountain machine pump set is provided with a water inlet pipe and a main drainage pipe, and the fountain waterscape control and protection device further comprises a water level monitoring assembly, an equipment protection assembly and a standby drainage pump; the water level monitoring assembly comprises a liquid level sensor; the equipment protection assembly comprises a controller and a voltmeter, and the fountain machine pump set is provided with a voltage stabilizer; according to the utility model, voltage monitoring can be carried out on the machine pump set of the fountain through the voltmeter, so that the working voltage of the machine pump set of the fountain is kept stable, and damage to machine pump equipment caused by unstable voltage is avoided; and through the liquid level sensor, when the water level of the waterscape pool rises due to voltage fluctuation, water can be drained through the standby drainage pump so that the water level can return to normal, and overlarge load of the drainage pump in the fountain machine pump is avoided.

The invention discloses a circuit fault detection control method, device and system based on an ammeter, and the method comprises the steps: responding to a maintenance mode triggered by a user, and transmitting a power supply starting signal to a DC power supply; receiving a detection signal acquired by the ampere-voltage meter and drawing a detection waveform according to a time sequence; extracting the received detection signals according to a time sequence of receiving the detection signals based on a data playback instruction triggered by a user to obtain reproduced signals; and returning a reproduction signal to the ampere-voltmeter signal according to the data playback instruction, so that the ampere-voltmeter displays the reproduction signal according to the time sequence to reproduce the acquisition process of the ampere-voltmeter for acquiring the detection signal, and during the period, the control system redraws the detection waveform according to the time sequence. The signal sampling process can be reproduced under the condition that a detection environment does not need to be additionally built, the workload of detection reproduction is reduced, and the redisk detection process of a user is facilitated.

A measuring system comprises a voltage converter circuit that converts and outputs a voltage between a first terminal and a second terminal, and a computing device that detects anomalies in the voltage converter circuit. The voltage converter circuit comprises: a first output circuit that outputs a first output voltage obtained by multiplying a potential of the first terminal with respect to a predetermined reference potential by a conversion gain; a second output circuit that outputs a second output voltage obtained by multiplying a potential of the second terminal with respect to the reference potential by a conversion gain; and a third output circuit that outputs a third output voltage obtained by multiplying a voltage between the first terminal and the second terminal by a conversion gain.The conversion gains of the first output circuit, the second output circuit, and the third output circuit can be set to values ​​of at least one first group and one second group, and the ratio between a first group conversion gain and a second group conversion gain set in the third output circuit differs from the ratio between a first group conversion gain and a second group conversion gain set in the first output circuit or the second output circuit.The computing device comprises the following: a voltmeter which measures the first output voltage, the second output voltage and the third output voltage, and a diagnostic unit which, using conversion gains of a selected group, which is one of the first group and the second group, calculates a first conversion value, a second conversion value and a third conversion value corresponding to input voltages of the first output circuit, the second output circuit and the third output circuit, based on the first output voltage, the second output voltage and the third output voltage, and determines that an anomaly exists if the sum of the first conversion value and the second conversion value deviates from the third conversion value by at least one predetermined value.

The invention provides an impedance regulation capability analysis method for a high-proportion renewable energy converter device, and belongs to the field of energy, and the method comprises the steps: constructing a PCC point voltage expression and a converter current frequency domain expression which do not consider a PWM (pulse width modulation) nonlinear link; the PCC point represents a common connection point; based on the PCC point voltage expression which does not consider the PWM nonlinear link, constructing a PCC point voltage expression which considers the frequency domain of the PWM nonlinear link; and based on the current frequency domain expression of the converter without considering the PWM nonlinear link and the PCC point voltage expression of the frequency domain of the PWM nonlinear link, constructing a grid-connected inverter sequence impedance model considering the PWM nonlinear link for analyzing the impedance adjustment capability of the renewable energy converter. The dynamic behavior of the renewable energy power generation equipment can be captured, and an analysis tool is provided for power grid operation and control.

1. Name of the product in this design: Graphical user interface for displaying battery power in electronic devices. 2. Purpose of this design: For use as a battery power display interface on a motorcycle voltage display panel. 3. The key design features of this product are its graphical user interface content. 4. The image or photograph that best illustrates the design's key features: the front view. 5. The rear view, left view, right view, top view, and bottom view have no design points, so the rear view, left view, right view, top view, and bottom view are omitted. 6. Human-computer interaction method of graphical user interface: The main view is the full-charge state of the color screen voltmeter, that is, the state after the voltmeter is fully charged and charging is turned off when the OFF button is clicked; clicking the ON button can switch to the changing state diagram 1, the color screen voltmeter interface is in the charging state; changing state diagram 2 is the low battery display of the color screen voltmeter; changing state diagram 3 is the discharge short circuit protection state of the color screen voltmeter.

The invention discloses a function detection device and method for a separation pin, an electric detonator and a thermal battery, and relates to the technical field of avionics, the function detection device comprises a control panel, and a power supply module, a low-resistance test module and a voltage and current test module which are installed on the control panel, and an externally used 220V power supply is sent to the power supply module through a fuse F1 and a power switch S1; after voltage stabilization and filtering of the power supply module, the voltage is converted into a required 27V linear direct-current power supply and instrument working voltage 24V, the instrument working voltage 5V, the 27V linear direct-current power supply is sent to a control panel through a fuse F2 and a 27V voltage switch S2, and the 27V linear direct-current power supply is connected in parallel with a 27V voltmeter PV0; instrument working voltage 24V is respectively sent to a control panel and a state indicating lamp through fuses F3 and F4, and instrument working voltage 5V is sent to a voltage and current test module and an instrument of the control panel. The device is easy to operate, accurate in measurement, capable of meeting detection requirements, safe and stable in operation and convenient to carry.

A diaphragm air pump performance test device belongs to the technical field of test devices and comprises a positive pressure sensor, a negative pressure sensor, an electromagnetic valve, an air compressor, a workbench, a single-chip microcomputer module, a test fixing seat, a flow meter, a voltmeter, a hose connector, a detection circuit and an alarm circuit. An isolation plate, a single-chip microcomputer module, a detection circuit and an alarm circuit are arranged in the workbench, a voltmeter is installed at the upper end in the workbench, and an air compressor is installed at the lower end in the workbench; the positive pressure sensor, the negative pressure sensor and the electromagnetic valve are installed on the partition plate, and the test fixing base is installed at the front end of the workbench. By means of simple switching of the power switch, input and output flow, input and output pressure data and generated negative pressure data of the diaphragm air pump in unit time can be detected, pressure maintaining data in unit time can also be detected, and when the pressure maintaining data is abnormal, a worker can be prompted to end the detection process in time through the alarm. According to the utility model, convenience is brought to workers, and detection data is more comprehensive.

The invention discloses a voltage detection method, a voltage detection device, electronic equipment and a computer readable storage medium, the detection method is applied to the electronic equipment, and the detection method specifically comprises the following steps: under the condition that the electronic equipment is accessed to a preset network, respectively sending channel establishment instructions to at least two target voltmeters, establishing a communication channel with each target voltmeter; the target voltmeter is a voltmeter determined by the electronic equipment based on a preset method; sending a network connection instruction to each target voltmeter based on the communication channel corresponding to each target voltmeter so as to instruct each target voltmeter to access a preset network; the network connection instruction comprises networking information of a preset network; detection voltages sent by the target voltmeters are received based on a preset network so as to complete voltage detection, and the detection voltages are voltages obtained by detecting the corresponding detection points through the target voltmeters. According to the method, different voltage detection scenes can be flexibly and efficiently coped with, so that the reliability of voltage detection is improved.

The utility model relates to the technical field of relays, and discloses a relay with a safety monitoring function, which comprises a relay body, a clamping seat, a digital display ampere-voltage meter, a thermometer, a heat dissipation assembly and a reinforcing assembly, a clamping seat is clamped on the outer side of the relay body and comprises a clamping plate and an insulating layer, the insulating layer wraps the outer side of the clamping plate, a thermometer is installed on one side of the clamping seat through an installation seat, heat dissipation assemblies are arranged on the two sides of the clamping seat and comprise ventilation boxes fixed to the two sides of the clamping seat in a penetrating mode through bolts, and draft fans are installed in the ventilation boxes through installation frames. Hanging plates are arranged at the tops of the clamping seats. Current and voltage of the relay body are monitored through the digital display ampere-voltage meter, the temperature of the relay body is monitored through the thermometer, and after the relay body is damaged, the clamping seat, the hanging plate, the thermometer, the digital display ampere-voltage meter and the like which are installed on the clamping seat and the hanging plate can be detached, so that the relay is convenient to use again and suitable for being widely popularized and used.

The invention discloses a circuit board fault detection signal data processing method, device and system, and the method comprises the steps: responding to a maintenance mode triggered by a user, and transmitting a power supply starting signal to a DC power supply; receiving a detection signal acquired by the ampere-voltage meter and drawing a detection waveform according to a time sequence; obtaining an interpretation target selected by the user, wherein the interpretation target is at least part of waveform selected by the user on the detection waveform; receiving waveform interpretation information input by the user in the input box in response to the selected interpretation target; and presenting waveform interpretation information to the user, and when the interpretation target is the partial waveform selected from the detection waveform, marking the interpreted position on the time sequence. Therefore, the data analysis process of the fault detection signal is simplified, and the data accuracy is improved while the working efficiency is improved.

A plasma processing apparatus includes a plasma processing chamber; a base; an electrostatic chuck; a plurality of electrode layers disposed in the same plane within the electrostatic chuck; a switch group including a plurality of first switches electrically connected to the electrode layers, respectively; a power supply and a measurement unit that are electrically connected to the switch group; a second switch that selects either the power supply or the measurement unit as a connection destination of the switch group; and a controller. The power supply includes a power source that supplies a power to the electrode layers. The measurement unit includes a resistor and a voltmeter that measures a voltage applied to the resistor. The controller is capable of executing a control operation that includes switching the connection destination of the switch group to the measurement unit and then turning ON the plurality of first switches one by one.

A photoelectric converter sensitivity adjusting device and method, comprising a light source module, a shielding cage, an optical fiber bundle, an optical power meter, a power supply, a photoelectric converter and a voltmeter, the light source module is used to generate test light, one end of the shielding cage is provided with a small hole for receiving the test light, the other end is provided with an optical fiber bundle connector connected with the optical fiber bundle, the test light entering the shielding cage from the small hole enters one end of the optical fiber bundle from the optical fiber bundle connector, the optical power meter is used to test the optical power emitted from the other end of the optical fiber bundle, the photoelectric converter has an optical fiber bundle connector and an output signal line, the optical fiber bundle connector is used to be detachably connected to the other end of the optical fiber bundle, and the voltmeter tests the output voltage of the photoelectric converter; the photoelectric converter is provided with a sensitivity adjusting resistor, and the output voltage can be changed under the same light intensity excitation. The device can shield the interference of environmental light in ordinary experimental environment, accurately adjust the sensitivity of the photoelectric converter, and has the advantages of low cost, high detection efficiency and convenient operation.