74 results about "Electrometer" patented technology

The invention discloses a mass spectrometer electrometer based on a capacitance integrator, and belongs to the technical field of electrometers. Comprising a capacitance integrator, the capacitance integrator is connected with a voltage holding circuit, the voltage holding circuit is connected with an acquisition control circuit and an amplification circuit, and the amplification circuit is connected with the acquisition control circuit; and the acquisition control circuit controls electric signals input into the capacitance integrator, the voltage holding circuit and the amplifying circuit through an I / V conversion control method, so that I / V conversion is completed. The capacitance integration is used for completing I / V conversion, the problem of high-resistance forbidding can be solved, meanwhile, compared with high-resistance conversion, the capacitance integration is adopted, the temperature stability of the electrometer is improved, and noise is reduced.

The invention relates to the technical field of TENG, in particular to a device and method for monitoring the lubrication state of a friction pair under the fluid lubrication condition based on TENG, and the device comprises a bearing which comprises an inner ring, an outer ring, a rolling body and a sealing ring, the outer ring is fixed in a center hole of a base, and the inner ring is provided with a stop screw hole for locking; the oil injection port is used for injecting lubricating oil into the bearing; one end of the wire is fixed on the inner ring, and the other end of the wire is connected to the electrometer to form a friction nano generator (TENG); the electrometer is used for detecting and outputting a current signal caused by the change of the friction state; the computer is connected with the electrometer and is used for receiving and analyzing the current signal; the base is used for bearing and fixing the bearing, mounting holes for mounting are formed in the base, mounting holes are symmetrically formed in the two sides of the base, and the base is fixed through bolts; the lubricating state is monitored based on the change of the electric signal generated by the change of the friction state of the TENG.

The invention discloses an electrometer based on constant temperature control, and belongs to the technical field of electrometers. Comprising an electrometer, the electrometer is connected with a temperature control component, a temperature control component circuit board is arranged in the temperature control component, and a temperature control circuit is arranged on the temperature control component circuit board; a refrigeration sheet and a temperature sensor are arranged in the cavity of the electrometer, and the refrigeration sheet and the temperature sensor are connected with a temperature control circuit through cables; and the temperature control circuit is used for receiving a temperature signal output by the temperature sensor and outputting a feedback control signal to the refrigeration sheet according to the temperature signal to adjust the temperature, so that the working temperature of the electrometer is constant. According to the invention, through the temperature control circuit, the temperature change caused by the external temperature change or the self-heating of the component can be reduced, the error caused by the temperature drift of the component is further reduced, and the stability of the electrometer is improved.

The invention relates to the technical field of electrometer measurement, and particularly discloses a high-precision electrometer based on an intelligent algorithm and a signal processing method thereof. The high-precision electrometer based on the intelligent algorithm comprises a capacitive sensor module, and the capacitive sensor module obtains an electrostatic signal and converts the electrostatic signal into a digital signal. The preprocessing module carries out noise suppression processing on the digital signals, external interference is removed, and the stability of the signals is improved. And the signal processing module performs feature extraction and analysis on the corrected signal by using a deep learning algorithm, so that the measurement precision is further improved. The correction output module obtains an error correction value through historical data fitting, calculates a final static value in combination with a static predicted value, and ensures the accuracy and reliability of a measurement result.

The invention discloses a non-contact moving object charge measurement method based on a mutual capacitance matrix, and belongs to the technical field of electrostatic detection. According to the invention, a physical model for charge measurement is constructed, a capacitance matrix is established by using a mirror image principle, a mutual capacitance value between a measured charged body and an induction electrode is solved by using a mirror image method, a circuit model for non-contact charge measurement is constructed, and the charge of the measured charged body is measured by using the model. Compared with a measurement method based on an electrometer, the non-contact type charge quantity measurement method has the advantages that the charge quantity of the to-be-measured charged body is not changed in the measurement process, repeated measurement is facilitated, and compared with an existing detection method based on an electric field sensor and the electric field change rate, a mathematical model for non-contact type charge quantity measurement is established; the corresponding relation between the charge quantity of the detected charged body and the amplitude of the electrostatic signal is accurately represented, and the method has a good application prospect in the field of electrostatic detection.

The invention relates to the technical field of photoelectric detection, in particular to a photocurrent imaging system based on a probe station and an electrometer. The system generates a focused detection light beam through a light path system, the focused detection light beam irradiates a sample carried by a probe station after being spatially modulated by a mask plate, weak light current signals generated by the sample are collected by an electrometer, and a high-resolution light current distribution image is generated by combining scanning motion of a high-precision electric control displacement platform and intelligent processing of computer software. A physically-driven signal enhancement model, a multi-dimensional noise suppression algorithm and a dynamic imaging optimization formula are innovatively designed, the problems that in the prior art, weak light current detection precision is low, the scale connection error is large, and imaging efficiency is insufficient are solved, accurate quantitative analysis of the photoelectric characteristics of materials is achieved, and the method is suitable for popularization and application. The method is suitable for semiconductor device research and development, solar cell performance evaluation, biosensor detection and other scenes, and has both detection precision and application flexibility.

The invention discloses a system and a method for measuring transient response electroluminescence of a light emitting diode, the system comprises a computer operation module, a voltage pulse input module, a light output detection module and the light emitting diode, the computer operation module comprises a pulse signal control module and a record memory, the control module is used for controlling the function signal generator and recording light output data; the voltage pulse input module comprises a function signal generator and a digital oscilloscope; the light output detection module comprises a photodiode probe and an electrometer and is used for detecting and collecting light output intensity of the light-emitting diode under different voltage pulses. The charge transfer time is determined according to the relation between the light output signal and the applied voltage pulse, the charge transfer distance is determined according to the thickness of the semiconductor film in the light-emitting diode, and the charge mobility of the semiconductor film can be calculated. No additional test sample needs to be prepared for the light-emitting diode, the charge transfer time and mobility in the device can be directly measured in a nondestructive manner, and the method is more convenient and accurate.

This invention relates to the field of thermal management and sensing monitoring technology, specifically an intelligent sensing system and method for the working fluid state within a pulsating heat pipe based on temperature monitoring. The method involves arranging pipe sections on a pulsating heat pipe, composed of alternating frictional and non-frictional materials. A ring-shaped copper electrode is attached to the outer wall of the frictional material section and connected to an electrometer, while thermocouples are used to measure temperature in the non-frictional material section. As the working fluid flows through the frictional section, it generates solid-liquid (vapor) frictional charge signals, which are transmitted synchronously with the temperature signal to a processing system. Feature extraction and model analysis are then used to perceive the working fluid's flow state and phase change characteristics in real time, thereby achieving intelligent sensing of the working fluid flow and heat transfer characteristics within the pipe. This invention has advantages such as simple structure, high real-time performance, high sensitivity, and non-invasive monitoring, and can be widely applied to the monitoring of the working fluid state and thermal performance analysis and evaluation of pulsating heat pipes and other phase change heat transfer components.

The invention belongs to the technical field of coal mine equipment static electricity elimination, and aims to solve the problem that the existing anti-static method is not ideal in elimination effect on static electricity generated on the surface of equipment. According to the anti-static device for the coal mine electrical automation equipment, a lead screw sliding block mechanism is installed in an inner cavity of a containing base, the directions of threads on the two sides of the middle of a lead screw in the lead screw sliding block mechanism are opposite, the two sides of the middle of the lead screw are each in threaded connection with a sliding block, and the upper end of each sliding block is connected with a first conductive plate; the outer side ends of the first conductive plates are connected with a grounding wire, and a space for clamping electrical equipment is formed between the two first conductive plates; the air ionization device comprises a power supply and a second conductive plate, the power supply is electrically connected with the second conductive plate and the controller, the electrometer is electrically connected with the controller, and the controller is an external controller; the pure water spraying device is used for spraying pure water to the surface of the electrical equipment. According to the invention, through combination of three modes of power connection, air ionization and pure water spraying, static elimination on the surface of the equipment is realized.

The present application relates to the field of intelligent sensor technology, and specifically to a method and system for measuring current through an electrometer of a radiation monitor, the method comprising: obtaining a pulse current signal of an electrometer in a radiation environment, dividing the pulse current sequence into pulse periods, obtaining the overshoot reaction degree in each pulse period according to the difference between each maximum value and the maximum value of the current in each pulse period, and the rate of change between adjacent maximum values ​​and minimum values ​​in the current value of each pulse period, and obtaining the ringing fluctuation deviation of each pulse period in combination with the degree of current fluctuation when ringing occurs in each pulse period, obtaining the distortion coefficient of each pulse period, analyzing the current change distribution of multiple sampling moments that are closest to the time interval of each sampling moment, and then obtaining an adaptive search window at each sampling moment, and filtering the pulse current to obtain the electrometer current measurement result. The present application can realize the accurate measurement of the electrometer current in the radiation environment.

The present application relates to the technical field of mass spectrometer signal processing, in particular to a mass spectrometer high resistance amplifier fast switching device and method, which is used to solve the problem that the existing mass spectrometer is complex in operation, time-consuming and may affect the performance of the amplifier during the amplifier replacement process; the device comprises an analysis tube and a plurality of receiving cups arranged in the analysis tube, and further comprises a switching circuit board and a plurality of high resistance amplifier modules, the plurality of high resistance amplifier modules are electrically connected to the switching circuit board, the signal input end of the switching circuit board is electrically connected with the plurality of analysis tubes, and the signal output end is connected with the data acquisition port of the mass spectrometer; the method comprises: using a U-shaped jumper to access a high resistance amplifier module with different resistance values according to ion flow with different abundances; the present application can quickly replace the resistance value without disassembling the amplifier, avoids damage caused by frequent disassembly of the instrument, and ensures the cleanliness of the electrometer cavity.

The invention relates to the technical field of mass spectrometers, in particular to a mass spectrometer electrometer which is used for solving the problem that the working stability of the electrometer is poor due to the fact that the temperature in an electrometer cavity of a mass spectrometer in a low-voltage state is not easy to control. The electrometer comprises a mounting base, an outer layer cavity and an inner layer cavity connected into the outer layer cavity are mounted on the mounting base, the inner layer cavity is connected to an external vacuum system, and an amplifier bottom plate and a circuit board bottom plate are mounted in the inner layer cavity; a heat preservation plate is filled between the outer-layer cavity and the inner-layer cavity, a heating piece is installed on the heat preservation plate, a heat conduction rod is rotationally connected into the heat preservation plate, an extension rod is fixedly connected to the first end of the heat conduction rod, and after the stop door is closed, the rotation angle of the heat conduction rod is increased along with the increase of the negative pressure strength of the inner-layer cavity; the contact area between the extension rod and the heating sheet is increased; according to the electrometer, the heat conduction efficiency is changed by adjusting the angle of the extension rod according to the negative pressure state, so that the working stability of the electrometer is improved.

The invention provides a charging and discharging current device and system for a solid-liquid multipurpose composite dielectric material. The charging and discharging current device mainly comprises a pressure tank, a three-electrode device (a high-voltage electrode, a test electrode and a leakage-proof current electrode), an electrometer, a program-controlled high-voltage power supply, a high-voltage relay, an air blast drying box and a computer. According to the invention, the charging and discharging current test of the liquid dielectric material can be realized, and the charging and discharging current test of solid-solid and solid-liquid multiphase composite dielectric materials can also be carried out; on the basis, a temperature control oven is added, and charge and discharge current detection at different temperatures can be carried out. The technical problems existing at present are solved, and charging and discharging current detection of the solid-liquid multipurpose composite dielectric material at different temperatures is achieved.

The invention relates to the technical field of oil flow live-line measurement, and discloses an ester-based insulating oil electrification degree detection device, a processing device and a control method thereof, and the device comprises an oil flow live-line box, an insulating pipeline section, a first permeation valve, an oil drop friction power generation unit, a second permeation valve and an electrometer; the oil flow electrified box is provided with a top end opening and a bottom end opening in the vertical direction; the insulating pipeline section is arranged in the oil flow electrified box; the first permeation valve is arranged at the top of the insulating pipeline section; the second permeation valve is arranged at the bottom of the insulating pipeline section; the first end of the oil drop friction power generation unit is connected with the first permeation valve; the second end of the drop friction power generation unit is connected with the second permeation valve; the oil drop friction power generation unit is used for being in friction contact with ester-based insulating oil to generate test charges; and the electrometer is connected with the oil drop friction power generation unit and is used for detecting the test charges to obtain the electrification degree of the ester-based insulating oil. According to the invention, the electrification degree detection precision of the ester-based insulating oil can be improved.

The present invention relates to the technical field of blue-green light detection materials, and in particular to a fully flexible blue-green light detection material, a preparation method thereof, and an application thereof. The fully flexible blue-green light detection material of the present invention utilizes the unique photoisomerization reaction of pseudostilbene azobenzene groups to blue-green light. The dynamic disorder of the molecular shape drives the microscopic contraction of the film fiber network, stimulating the piezoelectric polymer to output a voltage signal on a macroscopic scale, which can be amplified and detected by an electrometer to realize the detection of the blue-green light intensity. The present invention prepares a fiber film composite material with a microstructure through a material forming method that is simple to operate and can be continuously manufactured on a large area. The present invention utilizes light signals to cause the accumulation of mechanical stress inside the material system, which is further converted into an electric potential difference between the material surfaces through the piezoelectric effect, thereby establishing a continuous transmission mechanism of optical-mechanical-electrical signals, and can prepare a large-area, fast-response, long-life, self-driven intrinsic flexible blue-green light detector.

One example includes an electrometer system. The system includes a sensor cell comprising alkali metal atoms within, and an optical beam system configured to provide at least one optical beam through the sensor cell to provide a first Rydberg energy state of the alkali metal atoms, the at least one optical beam exiting the sensor cell as a detection beam. The system also includes a radio frequency (RF) tuning field generator configured to generate an RF tuning signal having a tuning frequency that is equal to an energy difference between the first Rydberg energy state and a second Rydberg energy state of the alkali metal atoms. The system further includes a detection system configured to monitor the detection beam to detect an external signal having a frequency that is between the first and second Rydberg energy states.

This utility model discloses a roller bonding machine for SCA adhesive, relating to the technical field of SCA adhesive bonding machines. It includes: a base, a worktable fixedly mounted on the top surface of the base, an electrical distribution box fixedly mounted on the left side wall of the base, a controller fixedly mounted on the front side wall of the worktable, a sliding groove on the top surface of the worktable, a movable plate on the top surface of the base, and two fixed blocks fixedly mounted on the top surface of the movable plate. A detection component is included. When the SCA adhesive, due to its high elasticity and thickness, generates static electricity and tends to curl, the adhesive surface instantly attracts the metal blocks, causing the movable blocks to compress a spring and trigger a microswitch. After the detection triggers, the microswitch directly activates an ion gun. The ion air is blown directionally onto the adhesive surface through a hose and air outlet, neutralizing static electricity. This avoids the interference of ambient light and humidity that traditional photoelectric or electrostatic meter solutions are susceptible to, significantly reducing the curling rate and improving the SCA adhesive bonding yield.

One example includes an electrometer system. The system includes a sensor cell comprising an alkali metal vapor within. The system also includes an excitation beam system configured to provide at least one excitation optical beam through the sensor cell to excite the alkali metal atoms from a ground state to a Rydberg energy state. The system also includes a stimulated emission beam system configured to provide a stimulated emission optical beam through the sensor cell to provide energy decay of the alkali metal atoms to a decay energy state that is less than the Rydberg energy state. The system further includes a detection system configured to monitor fluorescent detection light emitted from the alkali metal atoms as the alkali metal atoms decay from the decay state to the ground state to determine signal characteristics of an external signal based on an intensity of the fluorescent detection light.

A quantum device includes multiple spin qubits, multiple electrometers, each being capacitively coupled to one of the spin qubits, multiple injection-locked oscillators, each being coupled to one of the electrometers and designed to transmit an excitation signal to the electrometer to which it is coupled, each excitation signal having a different frequency, an amplification circuit comprising at least one amplifier, wherein the device comprises a feedback loop coupling the output of the amplification circuit to an input of each injection-locked oscillator and through which an injection signal flows, each injection-locked oscillator being designed to receive the injection signal and, as a function of the injection signal, maintain or decrease its excitation signal.

A low-temperature fluid flow electrostatic accumulation strength measurement experimental device and method, including a transmission pipe section and a test pipe section; the outside of the test pipe section is wrapped with a bare copper wire, and the test pipe section is provided with a copper mesh shield and a stainless steel square cavity shield; the inlet of the stainless steel square cavity shield is connected with the outlet of a first low-temperature ball valve and a low-temperature orifice flowmeter, the inlet of the low-temperature orifice flowmeter is connected with a first low-temperature stop valve and a transmission pipeline, and the outlet of the stainless steel square cavity shield is connected with a second low-temperature stop valve; the inlet of the test pipe section is connected with the outlet of a second low-temperature ball valve and a low-temperature orifice flowmeter; silver electrodes are arranged at the inlet and the outlet of the test pipe section; the outlet pipeline of the test pipe section extends into the inner container of a Faraday cylinder, and the BNC connector of the Faraday cylinder, the silver electrodes, the bare copper wire, the stainless steel square cavity shield, the copper mesh shield and an electrostatic meter are connected; the application studies the electrostatic accumulation current strength generated by the low-temperature working medium flowing in the pipe, and provides support for the electrostatic safety of a low-temperature propellant pipeline transmission system.

The utility model discloses an MOS antistatic function detection device, and specifically relates to the MOS detection technology field, comprising a work bench, the top end of the work bench is fixedly provided with a fixed seat, the outer side wall of the fixed seat is provided with a PWM square wave signal generator, the top of the front end of the fixed seat is fixedly connected with an arch-shaped frame, the inner side of the top of the arch-shaped frame is movably connected with a pressing rod, and the pressing rod is fixedly connected with the fixed seat. A sliding sleeve is fixedly connected to the bottom end of the arch-shaped frame, a sliding rod is arranged on the inner side of the sliding sleeve in a penetrating mode in the vertical direction, a hinged shaft wall is movably connected to the top end of the sliding rod, and the top end of the hinged shaft wall is movably connected with the end of the pressing rod. According to the utility model, limitation of a traditional measuring tool on MOS tube function detection can be effectively overcome, whether the MOS function is intact can be rapidly and effectively detected, whether the antistatic capability of the MOS is compliant can be checked by cooperating with an electrometer, whether the MOS is abnormal can be found only by function test after SMT pasting of the MOS, and the detection efficiency is improved. And the abnormal occurrence frequency and the abnormal product rejection rate are reduced.

One embodiment includes an electrometer system. The system includes a sensor cell comprising alkali metal atoms within and an optical beam system configured to provide at least one optical beam through the sensor cell to provide a Rydberg energy state of the alkali metal atoms, the at least one optical beam exiting the sensor cell as a detection beam. The system also includes a signal generator configured to generate a radio frequency (RF) tuning signal. The system also includes a waveguide extending along a length of the sensor cell, the waveguide being configured to propagate the RF tuning signal in the sensor cell to tune at least one energy state of the alkali metal atoms relative to the Rydberg energy state. The system further includes a detection system configured to monitor the detection beam to detect an external signal based on monitoring the detection beam.

The invention discloses a pyroelectric multichannel parallel testing device and testing method, and belongs to the technical field of pyroelectric testing of probe detection. The problem that in the prior art, a traditional pyroelectric testing device and a traditional pyroelectric testing method are low in testing efficiency is solved. The invention provides a pyroelectric multichannel parallel testing device which is characterized in that a temperature sensor and a heater are connected with a sample table, a high-low temperature heat table comprises the temperature sensor and the heater, the sample table and a multichannel testing clamp, the multichannel testing clamp comprises a probe table and probes on the probe table, the sample table is connected with the probe table, and the probe table is connected with the high-low temperature heat table. The multi-channel test clamp is connected with the multi-channel switching module and the electrometer. The temperature control module is respectively connected with the temperature sensor, the heater and the air pump; the air pump is respectively connected with the liquid nitrogen tank and the sample table; the main control end is connected with the temperature control module, the multi-channel switching module and the electrometer. According to the invention, the test efficiency is improved, automatic temperature regulation in a low-temperature and high-temperature range is realized, and the device can be applied to multi-sample pyroelectric test.

The application relates to the technical field of mass spectrometers, in particular to a mass spectrometer electrometer for solving the problem of poor working stability of the electrometer caused by the difficulty in controlling the temperature in the electrometer cavity of the mass spectrometer under a low pressure state; the electrometer comprises a mounting seat, an outer cavity is mounted on the mounting seat, an inner cavity is connected to the outer cavity, the inner cavity is connected to an external vacuum system, an amplifier bottom plate and a circuit board bottom plate are mounted in the inner cavity; a blocking door is hingedly connected to the mounting seat, a heat preservation plate is filled between the outer cavity and the inner cavity, a heating sheet is mounted on the blocking door, a heat conduction rod is rotatably connected in the heat preservation plate, a lengthening rod is fixedly connected to a first end portion of the heat conduction rod, after the blocking door is closed, the rotation angle of the heat conduction rod is increased with the increase of the negative pressure intensity of the inner cavity, so that the contact area between the lengthening rod and the heating sheet is increased; the electrometer adjusts the angle of the lengthening rod according to the negative pressure state, changes the heat conduction efficiency, and thus the working stability of the electrometer is improved.

The invention discloses a self-powered underwater contact type metal recognition device and method for an ultra-deep water environment. Belongs to the technical field of underwater metal material detection. The device comprises an induction electrode, a reference electrode and an electrometer, the positive electrode of the electrometer is connected with the induction electrode, the negative electrode of the electrometer is connected with the reference electrode, and the induction electrode is not in contact with the reference electrode; when metal identification is carried out, the induction electrode and the reference electrode are immersed in water, the induction electrode makes contact with metal to be detected, and the reference electrode does not make contact with the metal to be detected. According to the invention, a self-driven underwater electric signal generation method is utilized to realize underwater metal identification, and the problem of underwater metal identification under the condition of no power supply can be effectively solved.

The invention relates to an electric sensor (10) for a coherent longitudinal electromagnetic wave emitted by a biological object (1), the sensor comprising a tubular casing (11) comprising a barrel (12) having a front end (13) that is open and a rear end (14) that is closed on the upstream pole of a bipolar switch (15), wherein the downstream pole of the bipolar switch (13) is connected to a potential charge collector (16) made of diamagnetic material, preferably copper. The invention also relates to a system comprising an electrometer designed to co-operate with this sensor (10), and to a measurement method implementing the sensor and the electrometer.

The invention relates to the field of insulating materials, in particular to an insulating material surface charge and surface trap integrated in-situ measurement device which comprises a measurement cavity and a data acquisition system. The measuring cavity comprises a cavity shell, and an electrode, a three-axis screw rod sliding table group, a surface charge measuring unit and a surface trap testing unit which are positioned in the cavity shell; the data acquisition system comprises a static capacitance probe, an electrometer, an oscilloscope and a computer, and the measuring cavity is connected with the data acquisition system through the static capacitance probe; through the integrated design of integrating surface charge measurement and surface trap test in one device, continuous measurement of the same sample can be realized, damage caused by frequent movement of the sample is avoided, distributed measurement of surface charge space-time distribution, surface potential attenuation characteristics and surface trap distribution characteristics of an insulating material can be realized, and the measurement accuracy is improved. The experimental error is reduced, and the measurement efficiency and accuracy are improved.

The present invention discloses a kind of chemical ionization-differential mobility screening-mass spectrometry system and working method, belong to the field of molecular cluster measurement technology, the present invention includes: atmospheric pressure chemical ionization source system, planar differential mobility analyzer, sheath gas circulation system, ion transmission interface, aerosol electrometer, mass spectrometer and control system; Chemical ionization source system and planar differential mobility analyzer are connected, planar differential mobility analyzer and its sheath gas circulation system form a circulating gas path, and planar differential mobility analyzer transmits the sample ions to be tested to aerosol electrometer and mass spectrometer detection by a special ion transmission interface; Control system connects atmospheric pressure chemical ionization source system, planar differential mobility analyzer and its sheath gas circulation system and mass spectrometer, provides high voltage and data collection, storage and reading. The present invention can realize the chemical composition of gas / molecular clusters in gas phase and efficient online in-situ synchronous monitoring of mobility.

The utility model relates to the field of force and electricity measuring technology, in particular to an interface friction force and friction electric signal synchronous measuring device which comprises a linear driver used for fixing a sample below, an optical lever is suspended above the linear driver, and the top end of the optical lever is fixed through a fixer. The bottom end of the optical lever is provided with a tractor for fixing a sample above the optical lever, the laser transmitter is used for transmitting laser to the optical lever, the laser receiver is used for receiving the laser reflected by the optical lever, and an electrometer is connected between the sample above the optical lever and the sample below the optical lever through a wire. The measuring device with the optical lever is used for replacing a traditional force sensor, synchronous and high-precision measurement of friction force and friction current between a solid-solid sample or a solid-liquid sample can be achieved, and the problem that an existing experimental device is low in friction force and friction current measurement precision is effectively solved.