CN120801967B - LD pumping module insulation detection circuit - Google Patents
LD pumping module insulation detection circuitInfo
- Publication number
- CN120801967B CN120801967B CN202511299318.9A CN202511299318A CN120801967B CN 120801967 B CN120801967 B CN 120801967B CN 202511299318 A CN202511299318 A CN 202511299318A CN 120801967 B CN120801967 B CN 120801967B
- Authority
- CN
- China
- Prior art keywords
- insulation
- detection circuit
- module
- detection
- resistance value
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/14—Circuits therefor, e.g. for generating test voltages, sensing circuits
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Of Individual Semiconductor Devices (AREA)
Abstract
The invention relates to the technical field of design of an LD pumping module insulation detection scheme, in particular to an LD pumping module insulation detection circuit. Comprises an adjustable power supply, a signal injection module and an upper computer. The laser diode in the pumping module is driven to a low-resistance state by an adjustable power supply, the obstruction of nonlinear characteristics to detection is eliminated, a signal injection module injects micro-amplitude voltage signals into a positive electrode-shell and a negative electrode-shell double-loop, response current is synchronously measured, insulation resistance is calculated, and an upper computer compares the minimum value of the double-loop resistance with a threshold value to realize fault judgment. The method breaks through the inherent limitation of the traditional megameter in LD pumping module detection, solves the problem of missed detection caused by high-resistance masking, and realizes accurate insulation detection in the electrified state. The invention is suitable for the production inspection of the pump module and the recheck before the laser device assembly, and remarkably improves the reliability and the production yield of the product.
Description
Technical Field
The invention relates to the technical field of design of an LD pumping module insulation detection scheme, in particular to an LD pumping module insulation detection circuit.
Background
At present, insulation resistance value detection of an electric and electronic product is usually carried out by adopting a megohmmeter or an insulation resistance value tester under the condition that the product is not electrified.
The detection of the prior meter or insulation resistance tester is not suitable for the detection of the LD pumping module.
The LD pumping module is formed by packaging several to tens of laser diodes in series array, and the laser diodes in the series array are connected by gold tape, as shown in figure 1. Due to flaws caused by occasional factors in the production process, insulation faults may exist between the electrical parts in the LD pumping module, such as gold strips, and the module housing, resulting in reduced insulation performance and even short circuit, and causing adverse effects on the application of LD pumping.
The laser diode in the LD pumping module belongs to one of semiconductor light emitting diodes having typical nonlinear volt-ampere characteristics. The impedance characteristic of the semiconductor light-emitting diode presented to the outside is defined by R=U/I, and the smaller the current I passing through the semiconductor light-emitting diode is, the larger the ratio of U to I is, and the larger the resistance presented to the outside is.
The megohmmeter or insulation resistance tester used in conventional insulation detection has a small driving current capability, which is only a few mA or even hundreds of uA, in order to protect the tested equipment. When the megohmmeter or the insulation tester is used for detecting the insulation resistance value of the LD pumping module, if the insulation fault occurs in the middle of the laser diode series array, no matter whether the insulation resistance value of the anode-shell or the insulation resistance value of the cathode-shell of the LD pumping module is tested, part of semiconductor laser diodes can be connected in series in a test loop, the current in the test loop is limited by the driving current capacity of the megohmmeter or the insulation resistance value tester, and only a few mA or hundreds uA is detected, and the laser diode in the test loop presents high resistance due to the nonlinear volt-ampere characteristic of the laser diodes, so that the insulation resistance value detected by the megohmmeter or the insulation resistance value tester is a high resistance value, and further the characteristics of low resistance value and even short circuit of the insulation fault point are covered, so that the insulation fault cannot be effectively identified. The insulation fault cannot be effectively identified in production or before use, and the insulation fault of the LD pumping module can be discovered after being installed into a laser for use, causing abnormality or fault, and causing great economic loss.
Thus, the prior art is still to be further developed.
Disclosure of Invention
The invention aims to overcome the technical defects and provide an LD pump module insulation detection circuit so as to solve the problems existing in the prior art.
To achieve the above object, according to a first aspect of the present invention, there is provided an LD pump module insulation detection circuit comprising:
The laser diode comprises an adjustable power supply and a signal injection module, wherein the adjustable power supply is used for providing driving current for the LD pumping module so as to enable the laser diode to present a low-resistance state, and the signal injection module is used for injecting small signal voltage in the low-resistance state and measuring response current so as to calculate an insulation resistance value.
Specifically, the system further comprises an upper computer which is in communication connection with the signal injection module and is used for receiving and displaying the insulation resistance value.
Specifically, the signal injection module includes three detection output terminals respectively configured to be connected to the anode, the cathode and the casing of the LD pumping module, so as to form an anode detection loop and a cathode detection loop.
Specifically, the adjustable power supply can adjust the output voltage and the output current to adapt to the driving requirements of different LD pumping modules.
Specifically, the upper computer comprises a judging module for comparing the insulation resistance value with a preset threshold value to identify an insulation fault.
Specifically, the signal injection module injects a first small signal voltage u1 into the positive electrode detection loop and measures a first small signal current i1, injects a second small signal voltage u2 into the negative electrode detection loop and measures a second small signal current i2, calculates a positive electrode insulation resistance value R1 according to u1 and i1, and calculates a negative electrode insulation resistance value R2 according to u2 and i 2.
Specifically, the magnitudes of the first small signal voltage u1 and the second small signal voltage u2 are smaller than the output voltage of the adjustable power supply, so as to avoid interference with the low resistance state of the laser diode.
Specifically, the driving current range of the adjustable power supply is adjustable, so that the laser diode presents a low resistance state.
Specifically, the judging module is configured to take the smaller value of R1 and R2 as a final insulation resistance value R, compare R with a preset threshold, and judge that the insulation fault occurs if R is smaller than the threshold.
Specifically, the signal injection module comprises a voltage injection unit and a current detection unit, wherein the voltage injection unit generates u1 and u2, and the current detection unit measures i1 and i2 and transmits signals to the upper computer through an analog-to-digital converter.
Specifically, the electrical loop resistances in the positive electrode detection loop and the negative electrode detection loop are known, and the resistance value of the laser diode in the low resistance state is lower than 10Ω.
The beneficial effects are that:
1. The high-resistance masking effect is eliminated, namely, the laser diode is forced to enter a saturated conduction state by providing enough driving current through an adjustable power supply, so that the dynamic resistance of the laser diode is reduced to a negligible level, and the problem of masking fault points caused by the high-resistance characteristic of the laser diode in the traditional method is fundamentally eliminated.
2. The double-loop full-range coverage is that the signal injection module detects the double loops of the positive electrode-shell and the negative electrode-shell, and no matter the insulation fault point is positioned near the electrodes of the series array, in the middle or at any position of the gold strip, the double-resistance value comparison can be used for accurately positioning.
3. And the intelligent decision is error-proof, namely, the minimum value of the double-loop resistor is used as a decision basis, so that measurement deviation caused by residual impedance of part of laser tubes or loop asymmetry is avoided, and the fault identification accuracy is remarkably improved.
4. And the micro-disturbance safety detection is that the injection amplitude of the small signal voltage is strictly limited in the micro proportion of the output of the main power supply, so that the working point of the laser tube is ensured not to deviate, and the nondestructive detection is realized in the electrified state.
5. And the whole flow efficiency is optimized, namely automatic processing is realized from the loading of the driving current to the fault judgment, the single detection time consumption is obviously lower than that of a manual operation mode, and the high-speed inspection requirement of a production line is met.
6. The self-adaptive strong compatibility is that the adjustable power supply is suitable for pump modules with different specifications in a wide-range output mode, the judging threshold can be dynamically adjusted according to product standards, and the self-adaptive strong compatibility is suitable for research and development verification, production line quality inspection and client-side review full scenes.
Drawings
Fig. 1 is a schematic circuit connection diagram of an LD pump module insulation detection circuit according to an embodiment of the present invention.
Detailed Description
In order to make the technical solution of the present application better understood by those skilled in the art, the technical solution of the present application will be clearly and completely described in the following with reference to the accompanying drawings, and based on the embodiments of the present application, other similar embodiments obtained by those skilled in the art without making any inventive effort should be included in the scope of protection of the present application. In addition, directional words such as "upper", "lower", "left", "right", and the like, as used in the following embodiments are merely directions with reference to the drawings, and thus, the directional words used are intended to illustrate, not to limit, the application.
The invention will be further described with reference to the drawings and preferred embodiments.
It should be noted that, as a core energy source of the fiber laser, a Laser Diode (LD) pump module is generally formed by serially packaging a plurality of laser tubes through a gold ribbon. The insulation performance between the internal electrical components (such as gold tape and electrode) and the metal shell directly influences the safety of the whole machine. The traditional insulation detection adopts a megohmmeter or an insulation resistance tester, and the method is effective in detecting a conventional linear resistance device, but has fundamental defects when facing an LD pumping module. The reason is that semiconductor laser diodes have significant nonlinear volt-ampere characteristics and exhibit extremely high impedance (up to mega-ohms) at microampere drive currents provided by mega-ohms. If the insulation fault point is positioned in the middle of the laser tube series array, part of the laser tubes are inevitably connected in the detection loop in series, and the high-resistance characteristic of the detection loop can completely cover the low-resistance state of the actual insulation fault point, so that the test result is distorted. The prior art can not distinguish fault point resistance and laser tube impedance, so that insulation fault detection is missed. Such hidden danger may cause short-circuit accident after the module is installed, light causes downtime of the laser, and heavy burns out the optical component. Industry is urgent to need an insulation detection scheme aiming at a special structure of an LD pumping module, and accurate fault identification is realized on the premise of ensuring safety.
Referring to fig. 1, the invention provides an insulation detection circuit of an LD pump module, comprising:
The laser diode comprises an adjustable power supply and a signal injection module, wherein the adjustable power supply is used for providing driving current for the LD pumping module so as to enable the laser diode to present a low-resistance state, and the signal injection module is used for injecting small signal voltage in the low-resistance state and measuring response current so as to calculate an insulation resistance value.
It should be further noted that this embodiment provides an insulation detection circuit of an LD pump module, whose core is composed of an adjustable power supply and a signal injection module. The adjustable power supply outputs driving current to the LD pumping module to enable the laser diode connected in series in the module to enter a conducting state (namely, a low resistance state, a typical value is lower than 10Ω), and the signal injection module injects small signal voltage into the detection loop and synchronously measures response current when the laser diode is in the low resistance state, and calculates an insulation resistance value through ohm law. The method has the advantages that the problem that the insulation fault is covered due to the fact that the laser tube presents high resistance (1 MΩ) due to the fact that the driving current is insufficient in a traditional megohmmeter is thoroughly avoided by forcedly driving the laser diode to a low resistance state, and the effective identification of the insulation fault between the gold belt and the shell in the pumping module is achieved.
Specifically, the system further comprises an upper computer which is in communication connection with the signal injection module and is used for receiving and displaying the insulation resistance value.
It should be further described that the invention is additionally provided with an upper computer which is in communication connection with the signal injection module. The signal injection module transmits the calculated insulation resistance value to the upper computer in real time, and the upper computer displays the resistance value and the fault judgment result through a human-computer interface. The method has the beneficial effects that a closed loop detection system is constructed, visual processing of detection data is realized, operators can conveniently and rapidly judge the product quality, and the detection efficiency of a production line is improved.
Specifically, the signal injection module includes three detection output terminals respectively configured to be connected to the anode, the cathode and the casing of the LD pumping module, so as to form an anode detection loop and a cathode detection loop.
It should be further noted that the signal injection module is provided with three detection output ends, wherein the first output end is connected with the anode of the LD pumping module, the second output end is connected with the cathode, and the third output end is connected with the metal shell. Thereby forming a positive electrode detection circuit (positive electrode to the case) and a negative electrode detection circuit (negative electrode to the case). The double-loop design can cover any position (such as the vicinity of a positive electrode, the vicinity of a negative electrode or the middle part of a series array) where an insulation fault possibly occurs, and single-point detection blind areas are avoided.
Specifically, the adjustable power supply can adjust the output voltage and the output current to adapt to the driving requirements of different LD pumping modules.
It should be further noted that the adjustable power supply adopts a digital control voltage stabilizing source, and its output voltage range is 0-100V, and output current range is 0-50A adjustable. During operation, power supply parameters are set according to rated working voltage and current (for example, 30V/10A module) of the LD pumping module to be tested, so as to ensure that the laser diode reaches a saturated conduction state. The pump module detection device has the advantages that the pump module detection device is adaptive to detection requirements of pump modules with different specifications, is high in universality, and ensures the stability of a low-resistance state through accurate driving.
Specifically, the upper computer comprises a judging module for comparing the insulation resistance value with a preset threshold value to identify an insulation fault.
The upper computer built-in judging algorithm is used for receiving the positive insulation resistance value R1 and the negative insulation resistance value R2 uploaded by the signal injection module, comparing the positive insulation resistance value R1 and the negative insulation resistance value R2, taking the minimum value as a final insulation resistance value R, and triggering insulation fault alarm if the R is lower than a preset threshold value (such as 100k omega). The automatic judgment mechanism has the advantages that manual misjudgment is avoided, the preset threshold can be flexibly adjusted according to product standards, and quality control consistency is guaranteed.
Specifically, the signal injection module injects a first small signal voltage u1 into the positive electrode detection loop and measures a first small signal current i1, injects a second small signal voltage u2 into the negative electrode detection loop and measures a second small signal current i2, calculates a positive electrode insulation resistance value R1 according to u1 and i1, and calculates a negative electrode insulation resistance value R2 according to u2 and i 2.
It should be further noted that the signal injection module performs dual-loop synchronous detection by injecting a first small signal voltage u1 with a frequency of 1kHz and an amplitude of 10mV into the positive detection loop, measuring a response current i1 and calculating r1=u1/i 1, and injecting u2 with the same parameter into the negative detection loop, measuring i2 and calculating r2=u2/i 2. The method has the advantages that the small signal injection method (< 100 mV) does not interfere with the main driving circuit of the adjustable power supply, and high-precision measurement of the insulation resistance value is realized while the laser tube is ensured to keep a low resistance state.
Specifically, the magnitudes of the first small signal voltage u1 and the second small signal voltage u2 are smaller than the output voltage of the adjustable power supply, so as to avoid interference with the low resistance state of the laser diode.
Specifically, the driving current range of the adjustable power supply can be adjusted according to the requirement of the tested LD module, so that the laser diode presents a low resistance state.
It should be further noted that the driving current setting of the adjustable power supply is adjustable, and the current range reduces the dynamic resistance of the laser diode to below 10Ω. The laser tube has the beneficial effects of ensuring the reliable conduction of the laser tube and maximally eliminating the high-resistance masking effect.
Specifically, the judging module is configured to take the smaller value of R1 and R2 as a final insulation resistance value R, compare R with a preset threshold, and judge that the insulation fault occurs if R is smaller than the threshold.
It should be further noted that the determination module executes a "min-value first" logic that selects a smaller value as R after comparing R1 with R2. If R is less than or equal to 50kΩ (adjustable preset threshold), the insulation fault is judged, and if R is more than 50kΩ, the insulation fault is judged to be qualified. The method has the advantages that the worst insulation point is focused, misjudgment caused by residual impedance of part of laser tubes is avoided, and the fault detection rate is improved to more than 99%.
Specifically, the signal injection module comprises a voltage injection unit and a current detection unit, wherein the voltage injection unit generates u1 and u2, and the current detection unit measures i1 and i2 and transmits signals to the upper computer through an analog-to-digital converter.
It should be further noted that the hardware structure of the signal injection module includes a voltage injection unit (generating the accurate u1/u2 based on the DAC chip), a current detection unit (converting the i1/i2 into a voltage signal based on the high-precision operational amplifier and the sampling resistor), and an analog-to-digital converter (digitizing the analog signal by the 24-bit ADC). The digital signal is transmitted to the upper computer through the SPI interface. The low-signal-measurement anti-interference device has the beneficial effects that the modularized circuit design guarantees the anti-interference capability of small signal measurement, and the 24-bit ADC realizes microampere-level current resolution and high-sensitivity detection.
Specifically, the electrical loop resistances in the positive electrode detection loop and the negative electrode detection loop are known, and the resistance value of the laser diode in the low resistance state is lower than 10Ω.
It can be appreciated that the present invention realizes the function of effectively identifying the insulation fault of the LD pumping module by an adjustable power supply in combination with the circuit of the signal injection module, as shown in fig. 1. The LD pumping module insulation detection circuit consists of an adjustable power supply, a signal injection module and an upper computer.
The adjustable power supply adjusts the output voltage and current according to the pumping module to be detected, so that the adjustable power supply provides a large enough driving current for the semiconductor laser diode in the LD pumping module, and the semiconductor laser diode is in a low-resistance state.
The signal injection module is provided with three detection output ends which are respectively connected with the anode, the cathode and the shell of the LD pumping module to form two detection loops of an anode detection loop and a cathode detection loop. When the detection is executed, small signal voltages u1 and u2 are respectively injected into the positive electrode detection loop and the negative electrode detection loop, small signal currents i1 and i2 formed by the small signal voltages in the positive electrode detection loop and the negative electrode detection loop are detected, resistance values R1 and R2 of the positive electrode detection loop and the negative electrode detection loop can be respectively calculated according to the u1, the u2 and the i1 and the i2, the resistance values on the test cable and the LD pumping electric loop are considered to be very small and negligible, the semiconductor laser diode in the LD pumping module presents low resistance characteristics under the drive of an adjustable power supply at the moment, and the R1 and the R2 reflect insulation resistance values of insulation fault points detected from the positive electrode detection loop and the negative electrode detection loop.
Considering that the occurrence points of the insulation fault points are random, the number of the semiconductor laser diodes which are connected in series on the positive electrode detection loop and the negative electrode detection loop may not be consistent, so that the values of R1 and R2 may be different, and the smaller value can reflect the insulation resistance value of the insulation fault points more.
And taking the smaller value of R1 and R2 as a final detection value R, uploading the final detection value R to an upper computer for display, and judging whether insulation faults exist or not according to a threshold value preset by the upper computer.
It can be understood that the scheme drives the semiconductor laser diode to a low resistance state by setting a proper adjustable power supply, and then utilizes the signal injection module to inject small signal voltage to implement insulation resistance value detection in the state, so that the problems that the semiconductor laser diode presents high resistance characteristics under the traditional insulation resistance value detection method, the traditional detection method cannot effectively detect the insulation resistance value of the LD pumping module are effectively solved, and effective detection of the insulation resistance value of the LD pumping module and effective identification of insulation faults are realized.
It can be understood that the invention provides a circuit principle and a technical approach for solving the problem that the high resistance characteristic of the laser diode prevents insulation detection under low current;
It can be understood that the technical effects and advantages include solving the problem that the insulation resistance value of the LD pumping module cannot be effectively detected by the traditional detection method using a megameter or an insulation resistance value tester, and realizing effective detection of the insulation resistance value of the LD pumping module and effective identification of insulation faults.
The technical features described above may be arbitrarily combined. Although not all possible combinations of features are described, any combination of features should be considered to be covered by the description provided that such combinations are not inconsistent.
The above-described embodiments of the present invention do not limit the scope of the present invention. Any other corresponding changes and modifications made in accordance with the technical idea of the present invention shall be included in the scope of the claims of the present invention.
Claims (11)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202511299318.9A CN120801967B (en) | 2025-09-12 | 2025-09-12 | LD pumping module insulation detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202511299318.9A CN120801967B (en) | 2025-09-12 | 2025-09-12 | LD pumping module insulation detection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN120801967A CN120801967A (en) | 2025-10-17 |
| CN120801967B true CN120801967B (en) | 2025-12-09 |
Family
ID=97308730
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202511299318.9A Active CN120801967B (en) | 2025-09-12 | 2025-09-12 | LD pumping module insulation detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN120801967B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104166075A (en) * | 2014-07-21 | 2014-11-26 | 华北电力大学（保定） | Partial-discharge photoelectric detection system and method based on laser diode |
| CN109324231A (en) * | 2018-12-03 | 2019-02-12 | 苏州共元自控技术有限公司 | A kind of batteries of electric automobile group direct current insulation against ground resistor detecting device and method |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2286483A (en) * | 1994-02-04 | 1995-08-16 | Chung Hyung Dong | High power, pulsed laser diode driver incorporating low impedance storage capacitor |
| ITMO20060168A1 (en) * | 2006-05-29 | 2007-11-30 | M D Micro Detectors S P A | METHOD FOR SAFETY CHECKING THE LASER EMISSION POWER AND RELATED CIRCUIT. |
| US9160164B2 (en) * | 2010-03-02 | 2015-10-13 | Accumetrics, Inc. | Method and apparatus for fault detection of series diodes in rectifiers |
| JP2012079966A (en) * | 2010-10-04 | 2012-04-19 | Miyachi Technos Corp | Fiber laser processing device and laser diode power supply unit for excitation |
| CN102967766B (en) * | 2012-11-23 | 2015-08-19 | 广东易事特电源股份有限公司 | Double line photovoltaic inverter insulation against ground resistance without switching tube detection system and method |
| CN203965489U (en) * | 2014-06-17 | 2014-11-26 | 三泰电力技术（南京）股份有限公司 | A kind of shelf depreciation high voltage pulse generation device |
| US9720030B2 (en) * | 2015-06-08 | 2017-08-01 | Nxp Usa, Inc. | Systems and methods for testing a clamp function for insulated gate bipolar transistors |
| CA3016278A1 (en) * | 2016-03-29 | 2017-10-05 | Mitsubishi Electric Corporation | Laser light source module and method of specifying failure laser diode |
| CN119518400A (en) * | 2024-10-15 | 2025-02-25 | 中国工程物理研究院应用电子学研究所 | A fiber laser constant current drive circuit and fiber laser |
-
2025
- 2025-09-12 CN CN202511299318.9A patent/CN120801967B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104166075A (en) * | 2014-07-21 | 2014-11-26 | 华北电力大学（保定） | Partial-discharge photoelectric detection system and method based on laser diode |
| CN109324231A (en) * | 2018-12-03 | 2019-02-12 | 苏州共元自控技术有限公司 | A kind of batteries of electric automobile group direct current insulation against ground resistor detecting device and method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN120801967A (en) | 2025-10-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101363895B (en) | Method and system for detecting DC circuit faults | |
| CN111896374A (en) | A mine communication tensile cable on-off test device | |
| CN111965563A (en) | Flat cable detection device | |
| CN107861064A (en) | A kind of more serial power battery pack electrical property detection methods | |
| CN204228901U (en) | Local discharge detection device | |
| CN112098900B (en) | Testing device and testing method for cable connection state | |
| CN120801967B (en) | LD pumping module insulation detection circuit | |
| CN110118911B (en) | USBC cable test circuit | |
| CN102323510B (en) | Rapid and reliable flat cable assembly detection device | |
| CN205038186U (en) | A testing arrangement for electrochemical sensor of two electrodes | |
| CN112798903A (en) | Double-shielded cable fault detection method | |
| CN106680655A (en) | Device and method for detecting direct-current relay coil parallel diodes | |
| CN109031004A (en) | USB charging wire detection device | |
| CN114487905A (en) | Testing device and testing method for connection state and precision of cable connecting line | |
| US12366597B2 (en) | Grounding impedance measuring circuit and grounding impedance measuring method | |
| CN206945924U (en) | A kind of more serial power battery pack electrical property testing devices | |
| CN118671530A (en) | Large-sized steam turbine generator bearing insulation on-line detection device and method | |
| CN207181347U (en) | A kind of device that metal welding seam welding quality is tested with big DC current | |
| CN111505512B (en) | A system and method for measuring electrical performance parameters of a thermal battery in an unactivated state | |
| CN206756972U (en) | A kind of Kelvin's connecting fault detects circuit | |
| CN111238359A (en) | Intelligent detection method for transformer winding deformation based on frequency sweep impedance | |
| CN103018613A (en) | Line detection module and testing jig provided with same | |
| CN218037144U (en) | Alarm circuit for detecting contact resistance | |
| CN110470339B (en) | Portable cable integrated detection device and application method thereof | |
| CN210894568U (en) | Cable short-circuit fault point position measuring circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |