Current measuring equipment

Abstract

The utility model relates to the technical field of measuring equipment, and provides current measuring equipment, which comprises a power supply, a capacitor, a short-circuit wire, a short-circuit switch, a measuring circuit and a measuring switch, the power supply is connected with the capacitor, the measuring circuit is connected with the measuring switch, and the short-circuit wire is connected with the short-circuit switch. And the measuring switch and the short-circuit switch are respectively used for connecting the measuring circuit and the short-circuit wire between the power supply and the capacitor. When the capacitor leakage current measuring device is used, the short-circuit switch is closed to connect the short-circuit wire between the power supply and the capacitor when the capacitor to be measured is charged, or the measuring switch is closed to connect the measuring circuit between the power supply and the capacitor when the leakage current of the capacitor is measured. Physical isolation among the measuring circuit, the power supply and the capacitor in the current measuring equipment is realized, so that when the measured capacitor is uncontrollable, the measuring circuit is disconnected, and the measuring circuit, the power supply and the capacitor are protected from being damaged.

Description

TECHNICAL FIELD

[0001] The utility model relates to measuring equipment technical field, specifically, relate to a current measurement equipment. BACKGROUND

[0002] In modern electronic technology, micro current measurement equipment is widely used in various precision measurement and control systems. These devices can accurately measure micro current signals, such as current signals with a current value less than 1000 μA, which are widely used in medical devices, sensors, communication equipment and other fields. However, as the measurement accuracy improves, higher requirements are placed on the safety and reliability of the equipment.

[0003] In the prior art, micro current measurement equipment is usually used to measure the leakage voltage of a capacitor. During the charging and boosting process of the capacitor, a large current is generated inside the micro current measurement equipment, and the capacitor is at risk of breakdown. Once the capacitor breaks down, a large current may flow through the measurement equipment momentarily, causing damage to the measurement equipment. After the measurement is completed, the large discharge current of the capacitor may also generate a transient overvoltage between the measurement ports, causing damage to the measurement equipment. SUMMARY

[0004] The problem solved by the utility model is how to improve the safety of current measurement equipment.

[0005] To solve the above problems, the utility model provides a current measurement equipment.

[0006] In a first aspect, the utility model provides a current measurement equipment for measuring a current signal with a current value less than a preset threshold, comprising a power supply, a capacitor, a short circuit line, a short circuit switch, a measurement circuit and a measurement switch. The power supply is connected to the capacitor. The measurement circuit is connected to the measurement switch. The short circuit line is connected to the short circuit switch. The measurement switch is used to connect the measurement circuit between the power supply and the capacitor. The short circuit switch is used to connect the short circuit line between the power supply and the capacitor.

[0007] Optionally, the measurement circuit includes the ammeter.

[0008] Optionally, the ammeter is a DE B2983A picoammeter.

[0009] Optionally, the current measurement equipment includes a first lead and a second lead. The positive pole of the power supply and the first end of the capacitor are connected by the first lead. The negative pole of the power supply and the second end of the capacitor are connected by the second lead.

[0010] Optionally, the measurement switch is configured to connect the measurement circuit between the positive pole of the power supply and the first end of the capacitor, or the short circuit switch is configured to connect the short circuit line between the positive pole of the power supply and the first end of the capacitor.

[0011] Optionally, the current measurement device further comprises a diode, the diode is arranged on the first lead wire, the anode of the diode is connected with the positive pole of the power supply, and the cathode of the diode is connected with the positive pole of the capacitor.

[0012] Optionally, the current measurement device further comprises an auxiliary power supply, the positive pole of the auxiliary power supply is connected with the positive pole of the diode, and the negative pole of the auxiliary power supply is connected with the negative pole of the diode.

[0013] Optionally, the diode is a 1N4148 diode.

[0014] Optionally, the power supply is a constant-voltage constant-current direct-current power supply.

[0015] Optionally, the current measurement device further comprises a controller, the controller is electrically connected with the measurement switch and the short circuit switch respectively, and is configured to control closing or opening of the measurement switch and the short circuit switch respectively.

[0016] The current measurement device has the following advantages: when in use, the short circuit switch is closed to connect the short circuit line between the power supply and the capacitor when the capacitor to be measured is charged, or the short circuit switch is opened in time when a large current occurs in the capacitor to be measured during the charging and voltage boosting process, so as to avoid breakdown of the measurement device; or the measurement switch is closed to connect the measurement circuit between the power supply and the capacitor when the leakage current of the capacitor is measured, and the short circuit switch and the measurement switch are arranged, so as to physically separate the measurement circuit in the current measurement device from the power supply and the capacitor, so that the measurement circuit is disconnected when the capacitor to be measured is uncontrollable (for example, the capacitor generates transient overvoltage or overcurrent), and the measurement circuit, the power supply and the capacitor are protected from being damaged. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 FIG. 1 is a structural schematic diagram of a current measurement device according to an embodiment of the present application.

[0018] FIG. 1 is a structural schematic diagram of a current measurement device according to an embodiment of the present application.

[0019] 1- power supply; 2- capacitor; 3- short circuit line; 4- short circuit switch; 5- measurement circuit; 51- ammeter; 6- measurement switch; 7- diode. DETAILED DESCRIPTION

[0020] In order to make the above object, characteristics and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings. Although some embodiments of the present application are shown in the drawings, it should be understood that the present application can be realized in various forms, and should not be interpreted as being limited to the embodiments described herein, on the contrary, these embodiments are provided to make the present application more thorough and complete. It should be understood that the drawings and embodiments of the present application are only for illustrative purposes, and are not used to limit the protection scope of the present application.

[0021] The term "comprising" and variations thereof as used herein are open-ended, that is "including, but not limited to"; the term "based on" is "based, at least in part, on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". Related definitions of other terms will be given in the following description. It should be noted that the "first", "second", and the like concepts mentioned in the present application are only used to distinguish different devices, modules or units, and are not used to limit the functions performed by these devices, modules or units or the mutual dependency relationship.

[0022] It should be noted that the modification of "one" and "multiple" mentioned in the present application is illustrative and not restrictive, and those skilled in the art should understand that unless otherwise explicitly indicated in the context, it should be understood as "one or more".

[0023] To solve the problems in the above related technologies, the present embodiment provides a current measurement device, as shown in Figure 1 For measuring a current signal with a current value less than a preset threshold, the device comprises a power supply 1, a capacitor 2, a short circuit line 3, a short circuit switch 4, a measurement circuit 5 and a measurement switch 6. The power supply 1 is connected to the capacitor 2. The measurement circuit 5 is connected to the measurement switch 6. The short circuit line 3 is connected to the short circuit switch 4. The measurement switch 6 is used to connect the measurement circuit 5 between the power supply 1 and the capacitor 2. The short circuit switch 4 is used to connect the short circuit line 3 between the power supply 1 and the capacitor 2.

[0024] In particular, the current measuring device of the embodiment is generally used to measure the leakage current of the capacitor 2, and the leakage currents of different capacitors 2 are different, for example, the leakage current of an aluminum electrolytic capacitor 2 is generally between several hundred microamperes (μA) and several milliamperes (mA); the leakage current of a tantalum capacitor 2 is generally smaller, usually between tens of microamperes (μA) and several hundred microamperes (μA); the leakage current of a ceramic capacitor 2 is generally low, usually below several microamperes (μA), and some high-quality ceramic capacitors 2 can even be below 1 microampere (μA); the leakage current of a film capacitor 2 is also generally low, similar to a ceramic capacitor 2, and is generally less than several microamperes (μA). Therefore, the threshold is generally set to 1000 μA, which covers all types of capacitors 2.

[0025] In order to ensure that the electric field inside the capacitor 2 is in a stable state, simulate the state of the capacitor 2 under normal working conditions, and measure the inter-electrode leakage current of the capacitor 2, for example, a short-circuit line 3 is connected between the power supply 1 and the capacitor 2 by using a short-circuit switch 4, and the capacitor 2 is charged to a standard voltage by the power supply 1 for 60 seconds. It should be noted that the leakage voltage of the capacitor 2 is measured to judge the performance of the capacitor 2, for example, if the leakage voltage of the capacitor 2 is greater than or equal to a preset standard leakage voltage, it indicates that the performance of the capacitor 2 is unqualified, and if the leakage voltage of the capacitor 2 is less than the preset standard leakage voltage, it indicates that the performance of the capacitor 2 is qualified.

[0026] In use, only one of the short-circuit line 3 and the measuring circuit 5 can be connected between the power supply 1 and the capacitor 2, for example, when the capacitor 2 is charging, the short-circuit switch 4 is closed, the measuring switch 6 is opened, the short-circuit line 3 is connected in the charging circuit (wherein the charging circuit includes a loop formed by the power supply 1 and the capacitor 2) to charge the capacitor 2, after the charging is completed, the leakage voltage of the capacitor 2 is measured, the short-circuit switch 4 is opened, the measuring switch 6 is closed, the output of the power supply 1 is turned off, and the measuring circuit 5 is connected between the power supply 1 and the capacitor 2 to measure the leakage current of the capacitor 2.

[0027] In use, the embodiment can close the short-circuit switch 4 to connect the short-circuit line 3 between the power supply 1 and the capacitor 2 when charging the measured capacitor 2, or disconnect in time when a large current occurs during the charging and voltage rising process of the measured capacitor 2, to avoid breakdown of the measuring device; or close the measuring switch 6 to connect the measuring circuit 5 between the power supply 1 and the capacitor 2 when measuring the leakage current of the capacitor 2. By setting the short-circuit switch 4 and the measuring switch 6, the physical separation between the measuring circuit 5, the power supply 1 and the capacitor 2 in the current measuring device is realized, so that the measuring circuit 5 is disconnected when the measured capacitor 2 is uncontrollable (for example, the capacitor 2 generates a transient overvoltage or overcurrent), to protect the measuring circuit 5, the power supply 1 and the capacitor 2 from being damaged.

[0028] Optionally, the measuring circuit 5 comprises the ammeter 51 to measure the leakage current of the device under test.

[0029] Optionally, the ammeter 51 is a DE B2983A picoammeter.

[0030] Specifically, since the leakage current is very small, usually in microampere (μA), using a common ammeter 51, such as a digital multimeter, which covers a range from microampere (μA) to several amperes (A), the measurement of the leakage current is less accurate, thus, the embodiment uses a DE B2983A picoammeter to measure the leakage current, which has a current measurement range from picoampere (pA) to microampere (μA), and the specific maximum current range may be around several hundred microamperes (μA), which conforms to the unit of the leakage current, and provides a certain range of variation for the size variation of the leakage current, and the basic accuracy is usually between 0.01% and 0.1%, which enables it to provide high-precision measurement, especially in the case of small leakage current. In addition, the DE B2983A picoammeter has a low noise function, and the minimum sampling noise is usually in the range of several picoamperes (pA), which is very important for measuring small currents (such as 0.1 pA). In the low range, the resolution of B2983A can reach 0.1 pA or even smaller, making it suitable for very fine measurement tasks, further improving the accuracy of leakage current measurement.

[0031] Optionally, the charging circuit comprises a first lead and a second lead, the positive pole of the power supply 1 and the first end of the capacitor 2 are connected through the first lead, and the negative pole of the power supply 1 and the second end of the capacitor 2 are connected through the second lead.

[0032] Optionally, the measuring switch 6 is used to connect the measuring circuit 5 between the positive pole of the power supply 1 and the first end of the capacitor 2, or the short-circuit switch 4 is used to connect the short-circuit line 3 between the positive pole of the power supply 1 and the first end of the capacitor 2.

[0033] Specifically, the measuring circuit 5 and the short-circuit line 3 can only have one connected to the charging circuit, so when the measuring circuit 5 is closed, the short-circuit circuit needs to be disconnected, and when the short-circuit circuit is closed, the measuring circuit 5 is disconnected.

[0034] Optionally, the current measuring device further comprises a diode 77, which is arranged on the first lead, the anode of the diode 77 is connected to the positive pole of the power supply 1, and the cathode of the diode 77 is connected to the positive pole of the capacitor 2.

[0035] Specifically, the diode 77 is used to determine whether the short-circuit switch 4 or the measurement switch 6 is closed, for example, when the short-circuit switch 4 or the measurement switch 6 is closed, it is observed whether the diode 77 emits light, if it emits light, it indicates that the short-circuit switch 4 or the measurement switch 6 is closed, if it does not emit light, it indicates that the short-circuit switch 4 or the measurement switch 6 is not closed, the staff can repair the short-circuit switch 4 or the measurement switch 6 in time according to whether the diode 77 emits light.

[0036] Optionally, the current measuring device further comprises an auxiliary power supply, the positive electrode of the auxiliary power supply is connected with the positive electrode of the diode 77, and the negative electrode of the auxiliary power supply is connected with the negative electrode of the diode 77.

[0037] Optionally, the diode 77 is a 1N4148 diode 77.

[0038] Specifically, the 1N4148 diode 77 is suitable for the micro-current measuring circuit 5, and the switching speed of the 1N4148 diode 77 is fast, which is suitable for high-frequency applications such as switching power supply 1 and radio frequency circuit, the maximum reverse working voltage thereof is 100V, which can meet the needs of various common circuits, can withstand 1A of forward current, is suitable for most small signal rectification and switching applications, and is small, common and reliable, which can reduce the construction cost and volume of the current measuring device and increase the service life of the current measuring device.

[0039] Optionally, the power supply 1 is a constant voltage and constant current direct current power supply 1.

[0040] Specifically, the constant voltage and constant current direct current power supply 1 can provide stable output voltage and current, which can prevent the capacitor 2 from being overcharged or undercharged due to voltage fluctuation, effectively control the charging current by using the constant current mode, avoid damage to the capacitor 2 caused by excessive charging current, reduce heat generation, and prolong the service life of the capacitor 2. In the initial charging stage of the constant current, the charging current is constant, which can quickly charge the capacitor 2 to near its rated voltage, shorten the charging time, and the constant voltage control can effectively avoid the capacitor 2 from being subjected to voltage transient peak (impact) during the charging process, improve safety and stability. When the capacitor 2 is charged to the set voltage, the constant voltage and constant current power supply 1 can automatically switch state to prevent overcharging and maintain the safe working area of the capacitor 2. Moreover, the constant voltage and constant current power supply 1 has a monitoring function, which can monitor the current and voltage in real time and provide effective charging quality feedback.

[0041] Optionally, the current measuring device further comprises a controller, the controller is electrically connected with the measurement switch 6 and the short-circuit switch 4 respectively, and is used for controlling the closing or opening of the measurement switch 6 and the short-circuit switch 4 respectively.

[0042] Specifically, the measurement switch 6 and the short-circuit switch 4 in the embodiment can be automatically controlled by the electric controller, for example, when charging is needed, the controller controls the short-circuit switch 4 to be closed and the measurement switch 6 to be opened, when the leakage current is measured, the controller controls the measurement switch 6 to be closed and the short-circuit switch 4 to be opened.

[0043] In addition, the controller can monitor and give a warning to the action of the measurement switch 6 and the short-circuit switch 4 in combination with the diode 77 and devices such as an alarm and a sensor. For example, a light sensor and an alarm can be arranged at the diode 77, when the worker closes the short-circuit switch 4 or the measurement switch 6, the diode 77 emits light, the light sensor obtains the light signal of the diode 77 and feeds back to the controller, the controller does not trigger the alarm to work, and the short-circuit line 3 or the measurement circuit 5 is connected between the power supply 1 and the capacitor 2 to charge the measured device or measure the leakage current of the measured device; when the worker closes the short-circuit switch 4 or the measurement switch 6, the diode 77 does not emit light, the light sensor does not obtain the light signal of the diode 77 and feeds back to the controller, the controller triggers the alarm to work to prompt the worker to check.

[0044] Although the utility model discloses as above, the protection scope of the utility model is not limited to this only. The person skilled in the art can make various changes and modifications without departing from the spirit and scope of the utility model, and these changes and modifications will fall into the protection scope of the utility model.

Claims

1. A current measuring device, characterized by, The application relates to a current measuring device for measuring a current signal with a current value less than a preset threshold value, comprising a power supply (1), a capacitor (2), a short circuit line (3), a short circuit switch (4), a measuring circuit (5) and a measuring switch (6), wherein the power supply (1) is connected with the capacitor (2), the measuring circuit (5) is connected with the measuring switch (6), the short circuit line (3) is connected with the short circuit switch (4), the measuring switch (6) is used for connecting the measuring circuit (5) between the power supply (1) and the capacitor (2), and the short circuit switch (4) is used for connecting the short circuit line (3) between the power supply (1) and the capacitor (2).

2. The current measuring device of claim 1, wherein, The measuring circuit (5) comprises an ammeter (51).

3. The current measuring device of claim 2, wherein, The ammeter (51) is a DE B2983A picoammeter.

4. The current measuring device of claim 1, wherein, The current measuring device comprises a first lead wire and a second lead wire, wherein a positive pole of the power supply (1) and a first end of the capacitor (2) are connected through the first lead wire, and a negative pole of the power supply (1) and a second end of the capacitor (2) are connected through the second lead wire.

5. The current measuring device of claim 4, wherein, The measuring switch (6) is used for connecting the measuring circuit (5) between the positive pole of the power supply (1) and the first end of the capacitor (2), or the short circuit switch (4) is used for connecting the short circuit line (3) between the positive pole of the power supply (1) and the first end of the capacitor (2).

6. The current measuring device of claim 4, wherein, The current measuring device further comprises a diode (7), wherein the diode (7) is arranged on the first lead wire, an anode of the diode (7) is connected with the positive pole of the power supply (1), and a cathode of the diode (7) is connected with the positive pole of the capacitor (2).

7. The current measuring device of claim 6, wherein, The current measuring device further comprises an auxiliary power supply, wherein a positive pole of the auxiliary power supply is connected with the positive pole of the diode (7), and a negative pole of the auxiliary power supply is connected with the negative pole of the diode (7).

8. The current measuring device of claim 6, wherein, The diode (7) is a 1N4148 diode (7).

9. The current measuring device of claim 1, wherein, The power supply (1) is a constant-voltage constant-current direct-current power supply (1).

10. The current measuring device of claim 1, wherein, The current measuring device further comprises a controller, wherein the controller is electrically connected with the measuring switch (6) and the short circuit switch (4) respectively, and is used for controlling the closing or opening of the measuring switch (6) and the short circuit switch (4) respectively.

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