Portable current detection device

Abstract

The utility model discloses a portable current detection device, relates to the technical field of current detection, the portable current detection device comprises a housing, a power supply unit, a sampling resistor, a control unit and a display unit are arranged in the housing, the power supply unit is respectively connected with the control unit and the display unit and supplies power to the control unit and the display unit, and the sampling resistor is connected with the sampling resistor. The sampling resistor is used for being connected with current to be measured, the control unit is connected with the sampling resistor and used for obtaining voltage values at the two ends of the sampling resistor, and the display unit is connected with the control unit and used for displaying the current value of the current to be measured. The control unit calculates the current value of the current to be measured by obtaining the voltage values at the two ends of the sampling resistor, the small current can be measured without using a table-type multimeter and a handheld multimeter, and the measuring device is small in size and convenient to carry, improves the convenience of current measurement, and reduces the measurement cost.

Description

Technical Field

[0001] This utility model relates to the field of current detection technology, and in particular to a portable current detection device. Background Technology

[0002] Current detection is an important part of electronic engineering and industrial production. By selecting appropriate detection methods and equipment, it is possible to ensure accurate and reliable acquisition of the required current information, thereby improving the efficiency and reliability of circuit analysis, fault diagnosis, and energy management.

[0003] In existing technologies, current detection is generally performed using handheld multimeters and benchtop multimeters. However, when conducting tests at outdoor production sites, benchtop multimeters are bulky and inconvenient to use, while handheld multimeters are expensive, resulting in high testing costs. Utility Model Content

[0004] This utility model provides a portable current detection device to solve the technical problems of existing benchtop multimeters being inconvenient to use outdoors and handheld multimeters being expensive and costly to test.

[0005] This utility model provides a portable current detection device, including:

[0006] The housing contains a power supply unit, a sampling resistor, a control unit, and a display unit.

[0007] The power supply unit is connected to and supplies power to the control unit and the display unit, respectively.

[0008] The sampling resistor is used to connect to the current to be measured;

[0009] The control unit is connected to the sampling resistor and is used to obtain the voltage value across the sampling resistor;

[0010] The display unit is connected to the control unit and is used to display the current value of the current to be measured.

[0011] In some embodiments, the control unit includes:

[0012] The current detection amplifier U2 has its third and fourth pins connected to the sampling resistor R5 to acquire the voltage value across the sampling resistor R5.

[0013] Voltage follower U1, the third pin of which is connected to the first pin of current sense amplifier U2, is used to obtain the voltage value across the sampling resistor R5.

[0014] In some embodiments, the control unit further includes:

[0015] The controller U3, whose forty-third pin is connected to the first pin of the voltage follower U1, is used to convert the voltage value across the sampling resistor R5 into the current value of the current to be measured.

[0016] In some embodiments, the power supply unit includes:

[0017] A battery management circuit, which is connected to a power source and a lithium battery respectively, is used to transmit the power source voltage to the lithium battery and charge it;

[0018] A voltage conversion circuit, wherein the input terminal of the voltage conversion circuit is connected to the power supply or the lithium battery, and the output terminal of the voltage conversion circuit is connected to the control unit and the display unit, for converting the voltage of the power supply or the lithium battery into a preset voltage.

[0019] In some embodiments, the battery management circuit includes:

[0020] The system includes a charging manager U6, resistors R11 and R10, a capacitor C11, a charging indicator LED1, and a full charge indicator LED2. The second pin of the charging manager U6 is connected to the first terminal of resistor R11, and the second terminal of resistor R11 is grounded. The fourth pin of the charging manager U6 is connected to the first terminal of capacitor C11, the first terminal of resistor R10, and the power supply. The second terminal of capacitor C11 is grounded. The second terminal of resistor R10 is connected to the positive terminals of both the charging indicator LED1 and the full charge indicator LED2. The negative terminal of the charging indicator LED1 is connected to the seventh pin of the charging manager U6. The negative terminal of the full charge indicator LED2 is connected to the sixth pin of the charging manager U6. The fifth pin of the charging manager U6 is connected to the lithium battery.

[0021] In some embodiments, the voltage conversion circuit includes:

[0022] The system includes resistors R13 and R14, capacitor C13, resistor R8, diode D2, transistor Q1, switch SW1, capacitor C9, capacitor C10, and a switching power supply module U5. The power supply, resistors R13 and R14 are connected sequentially and grounded. The first terminal of capacitor C13 is connected to the second terminal of resistor R13, and the second terminal is grounded. The first terminal of resistor R8 is connected to the power supply, and the second terminal is grounded. The gate of transistor Q1 is connected to the power supply and the first terminal of resistor R13. The drain of transistor Q1 is connected to the lithium battery. The source of transistor Q1 is connected to the cathode of diode D2 and the first terminal of switch SW1. The anode of diode D2 is connected to the first terminal of resistor R13. The second terminal of switch SW1 is connected to the third terminal of switching power supply module U5. The first terminal of switching power supply module U5 is grounded. The first terminal of capacitor C9 is connected to the third terminal of switching power supply module U5. The second terminal of capacitor C9 is grounded. The first terminal of capacitor C10 is connected to the second terminal of switching power supply module U5. The second terminal of capacitor C10 is grounded.

[0023] In some embodiments, the portable current detection device further includes:

[0024] A reference voltage unit is provided, with its input terminal connected to the voltage conversion circuit and its output terminal connected to the controller U3. The reference voltage unit is used to convert the preset voltage output by the voltage conversion circuit into a reference voltage and output it to the controller U3.

[0025] In some embodiments, the reference voltage unit includes:

[0026] The system includes a resistor R3, a capacitor C5, a capacitor C6, a resistor R4, a capacitor C7, and a voltage regulator U4. The first terminal of resistor R3 is connected to the second terminal of the switching power supply module U5. The second terminal of resistor R3 is connected to the first terminals of capacitors C5, C6, and R4, and to the thirteenth pin of the controller U3. The second terminals of capacitors C5 and C6 are grounded. The second terminal of resistor R4 is connected to the first terminal of capacitor C7, and the second terminal of capacitor C7 is grounded. The first and second terminals of voltage regulator U4 are both connected to the second terminal of resistor R4 and the twelfth pin of the controller U3. The third terminal of voltage regulator U4 is grounded.

[0027] In some embodiments, the display unit includes:

[0028] The pin header interface H1 has a first pin grounded, a second pin connected to the voltage conversion circuit, a third pin connected to the thirty-eighth pin of the controller U3, and a fourth pin connected to the thirty-seventh pin of the controller U3.

[0029] The display screen is mounted on the housing and connected to the third and fourth pins of the pin header interface H1, respectively, for displaying the current value of the current to be measured.

[0030] In some embodiments, the portable current detection device further includes:

[0031] The serial port chip U7 is connected to the controller U3 at its input terminal and is used to receive the current value of the current to be measured output by the controller U3.

[0032] The output port USB1 is connected to the output of the serial port chip U7, and is used to transmit the current value of the current to be measured output by the controller U3 to the host computer.

[0033] The beneficial effects of the technical solution provided by this utility model include:

[0034] This utility model provides a portable current detection device, including a housing. The housing houses a power supply unit, a sampling resistor, a control unit, and a display unit. The power supply unit is connected to and supplies power to both the control unit and the display unit. The sampling resistor is connected to the current to be measured. The control unit is connected to the sampling resistor and acquires the voltage across the sampling resistor. The display unit is connected to the control unit and displays the current value of the current to be measured. The control unit calculates the current value of the current to be measured by acquiring the voltage across the sampling resistor. This device allows for the measurement of small currents without the need for a benchtop multimeter or a handheld multimeter. Furthermore, its small size and portability improve the convenience of current measurement and reduce measurement costs. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A schematic diagram of the structure of a portable current detection device provided in an embodiment of this utility model;

[0037] Figure 2Circuit diagram of the control unit provided in the embodiment of this utility model;

[0038] Figure 3 A circuit diagram of the controller provided for an embodiment of this utility model;

[0039] Figure 4 A circuit diagram of the battery management circuit provided for an embodiment of this utility model;

[0040] Figure 5 A circuit diagram of the voltage conversion circuit provided in an embodiment of this utility model;

[0041] Figure 6 A circuit diagram of a reference voltage unit provided for an embodiment of this utility model;

[0042] Figure 7 A circuit diagram of the pin header interface provided for an embodiment of this utility model;

[0043] Figure 8 Circuit diagram of the serial port chip and output port provided for embodiments of this utility model;

[0044] Figure label:

[0045] 1. Housing; 11. Input terminal for the current to be measured; 12. Output terminal for the measurement result;

[0046] 2. Display screen. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0048] This utility model provides a portable current detection device, which can solve the technical problems of existing benchtop multimeters being inconvenient to use outdoors and handheld multimeters being difficult to accurately detect small current signals.

[0049] Figure 1This utility model provides a portable current detection device, comprising: a housing 1, wherein the housing 1 is provided with a power supply unit, a sampling resistor, a control unit and a display unit, the power supply unit is connected to and supplies power to the control unit and the display unit respectively, the sampling resistor is used to connect to the current to be measured, the control unit is connected to the sampling resistor and is used to obtain the voltage value across the sampling resistor, the display unit is connected to the control unit and is used to display the current value of the current to be measured, one side of the housing 1 is provided with two current input terminals 11 to be measured and respectively connected to the sampling resistor, and the other side of the housing 1 is also provided with two measurement result output terminals 12 and connected to a host computer.

[0050] The portable current detection device provided in this embodiment of the utility model has a housing, within which are a power supply unit, a sampling resistor, a control unit, and a display unit. The power supply unit is connected to and supplies power to the control unit and the display unit respectively. The sampling resistor is used to connect to the current to be measured. The control unit is used to obtain the voltage value across the sampling resistor. The display unit is connected to the control unit and is used to display the current value of the current to be measured. Since the resistance of the sampling resistor remains constant, after the control unit obtains the voltage value across the sampling resistor, it can calculate the current value flowing through the sampling resistor according to Ohm's law. The display unit then displays the current value calculated by the control unit for human reading. Small currents can be measured without the need for a benchtop multimeter or a handheld multimeter. Furthermore, this measuring device is small in size, easy to carry, improves the convenience of current measurement, and reduces measurement costs.

[0051] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 2As shown, the control unit includes a current-sensing amplifier U2 and a voltage follower U1. The third and fourth pins of the current-sensing amplifier U2 are both connected to the sampling resistor R5 to acquire the voltage value across R5. The third pin of the voltage follower U1 is connected to the first pin of the current-sensing amplifier U2 to acquire the voltage value across R5. The fifth pin of the current-sensing amplifier U2 is connected to the power supply unit, which supplies power to the current-sensing amplifier U2. The fifth pin of the current-sensing amplifier U2 is also grounded through capacitor C2. When the measured current flows through... When the sampling resistor R5 is used, the current detection amplifier U2 collects the voltage value across the sampling resistor R5 and transmits it to the voltage follower U1. The second pin of the voltage follower U1 is grounded through capacitor C1, and the eighth pin of the voltage follower U1 is grounded through capacitor C8. The eighth pin of the voltage follower U1 is also connected to the power supply unit. The voltage follower U1 is used to amplify and transmit the voltage signal, so that the voltage signal is amplified to a certain extent during transmission, thereby improving the reliability and readability of the voltage signal. The capacitors C2, C1, and C8 are all filter capacitors used to filter out circuit ripple.

[0052] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 3 As shown, the control unit further includes: a controller U3, the forty-third pin of which is connected to the first pin of the voltage follower U1, for converting the voltage value across the sampling resistor R5 into the current value of the current to be measured. Capacitors C3 and C4 are connected in parallel between the fifteenth and seventeenth pins of the controller U3. The fifteenth pin of the controller U3 is also connected to the power supply unit, which supplies power to the controller U3. The controller U3 calculates the current value flowing through the sampling resistor R5 based on the voltage value across the sampling resistor R5, thereby detecting the current value of the current to be measured and transmitting it to the display unit.

[0053] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 4As shown, the power supply unit includes a battery management circuit and a voltage conversion circuit. The battery management circuit is connected to both a power source and a lithium battery, and is used to transmit the power source voltage to the lithium battery and charge it. The input terminal of the voltage conversion circuit is connected to either the power source or the lithium battery, and the output terminal of the voltage conversion circuit is connected to the control unit and the display unit, and is used to convert the voltage of the power source or the lithium battery into a preset voltage. The battery management circuit is used to connect to the power source and charge the lithium battery. The voltage conversion circuit selects to convert the voltage of the power source or the lithium battery into a preset voltage of 3.3V and outputs it to the control unit and the display unit to power them, depending on whether the power source or the lithium battery is used.

[0054] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 4 As shown, the battery management circuit includes: a charging manager U6, resistors R11 and R10, a capacitor C11, a charging indicator LED1, and a full charge indicator LED2. The second pin of the charging manager U6 is connected to the first terminal of resistor R11, and the second terminal of resistor R11 is grounded. The fourth pin of the charging manager U6 is connected to the first terminal of capacitor C11, the first terminal of resistor R10, and the power supply. The second terminal of capacitor C11 is grounded. The second terminal of resistor R10 is connected to the positive terminals of the charging indicator LED1 and the full charge indicator LED2. The negative terminal of the charging indicator LED1 is connected to the seventh pin of the charging manager U6, and the negative terminal of the full charge indicator LED2 is connected to the sixth pin of the charging manager U6. The fifth pin of the charging manager U6 is connected to the lithium battery VBAT. When the power supply VBUS charges the lithium battery VBAT through the charging manager U6, the charging indicator LED1 lights up to show that it is charging. When the lithium battery VBAT is fully charged, the sixth pin of the charging manager U6 outputs a low level, and the full charge indicator LED2 lights up to show that it is fully charged. If the lithium battery VBAT is not fully charged, the sixth pin of the charging manager U6 outputs a high level, and the full charge indicator LED2 does not light up. The resistors R11 and R10 can stabilize the circuit, reduce circuit interference, and protect the equipment. The capacitor C11 is a filter capacitor used to filter out power supply noise and AC components.

[0055] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 5As shown, the voltage conversion circuit includes: resistor R13, resistor R14, capacitor C13, resistor R8, diode D2, transistor Q1, switch SW1, capacitor C9, capacitor C10, and switching power supply module U5. The power supply, resistor R13, and resistor R14 are connected in sequence and grounded. The first terminal of capacitor C13 is connected to the second terminal of resistor R13, and the second terminal is grounded. The first terminal of resistor R8 is connected to the power supply, and the second terminal is grounded. The gate of transistor Q1 is connected to the power supply and the first terminal of resistor R13. The drain of transistor Q1 is connected to the lithium battery. The source of transistor Q1 is connected to the negative terminal of diode D2 and the first terminal of switch SW1. The positive terminal of diode D2 is connected to the first terminal of resistor R13. The second terminal of switch SW1 is connected to the third terminal of switching power supply module U5. The first terminal of switching power supply module U5 is grounded. The first terminal of capacitor C9 is connected to the third terminal of switching power supply module U5. With both ends grounded, the first end of capacitor C10 is connected to the second end of the switching power supply module U5, and the second end of capacitor C10 is grounded. After the switch SW1 is turned on, the lithium battery voltage VBAT is transmitted to the switching power supply module U5 through the transistor Q1. The switching power supply module U5 converts the lithium battery voltage VBAT to a preset voltage of 3.3V. When a power supply voltage VBUS is transmitted to the third end of the switching power supply module U5 through the diode D2, the transistor Q1 is disconnected and cuts off the power supply to the lithium battery VBAT, switching to power supply voltage VBUS. Then, the switching power supply module U5 converts the power supply voltage VBUS to the preset voltage of 3.3V. The preset voltage of 3.3V is connected to and powers the current detection amplifier U2, the voltage follower U1, and the controller U3 respectively. Resistors R13 and R14 are used to stabilize the circuit and reduce circuit interference. Capacitors C13, C9, and C10 are filter capacitors used to filter out circuit ripple.

[0056] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 6 As shown, the portable current detection device further includes: a reference voltage unit, the input terminal of which is connected to the voltage conversion circuit, and the output terminal of which is connected to the controller U3. The reference voltage unit is used to convert the preset voltage output by the voltage conversion circuit into a reference voltage and output it to the controller U3. The reference voltage unit is used to determine the accurate amplitude of the measured current value for the controller U3, thereby enabling the controller U3 to convert the measured analog value into a digital value.

[0057] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 6As shown, the reference voltage unit includes: resistor R3, capacitor C5, capacitor C6, resistor R4, capacitor C7, and voltage regulator U4. The first terminal of resistor R3 is connected to the second terminal of the switching power supply module U5. The second terminal of resistor R3 is connected to the first terminals of capacitors C5, C6, and R4, and the thirteenth pin of controller U3. The second terminals of capacitors C5 and C6 are grounded. The second terminal of resistor R4 is connected to the first terminal of capacitor C7, and the second terminal of capacitor C7 is grounded. The first and second terminals of voltage regulator U4 are both connected to the second terminal of resistor R4 and the twelfth pin of controller U3. The third terminal of voltage regulator U4 is grounded. Voltage regulator U4 converts the preset voltage of 3.3V output by the switching power supply module U5 into a reference voltage of 2.5V and transmits it to the twelfth pin of controller U3, i.e., ADC_V. The Ref pin is used by the controller U3 to output a corresponding value based on the voltage value across the sampling resistor R5 and the reference voltage 2.5V. During analog-to-digital conversion, 2.5V serves as the conversion standard. The reference voltage 2.5V can accurately quantize and process analog signals, ensuring the stability and accuracy of the circuit. That is, if the voltage across the sampling resistor R5 is 2.5V, the controller U3 outputs a digital value representing the full scale; if the voltage across the sampling resistor R5 is 0V, the controller U3 outputs a digital value representing zero. Capacitors C5, C6, and C7 are all filter capacitors.

[0058] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 7 As shown, the display unit includes a pin header interface H1 and a display screen 2. The first pin of the pin header interface H1 is grounded, the second pin is connected to the voltage conversion circuit, the third pin is connected to the thirty-eighth pin of the controller U3, and the fourth pin is connected to the thirty-seventh pin of the controller U3. The display screen 2 is disposed on the housing 1 and is connected to the third and fourth pins of the pin header interface H1 respectively, for displaying the current value of the current to be measured. The controller U3 communicates with the display screen 2 through the IIC protocol and displays the current measurement result on the display screen 2 for human reading.

[0059] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 8As shown, the portable current detection device further includes: a serial port chip U7 and an output port USB1. The input terminal of the serial port chip U7 is connected to the controller U3 for receiving the current value of the current to be measured output by the controller U3. The input terminal of the output port USB1 is connected to the output terminal of the serial port chip U7 for transmitting the current value of the current to be measured output by the controller U3 to the host computer. The seventh pin of the serial port chip U7 is connected to the twentieth pin, i.e., the TXD pin, of the controller U3 through a resistor R14. The sixth pin of the serial port chip U7... The pin is connected to the nineteenth pin (RXD pin) of the controller U3 via diode D1. The serial port chip U7 is used to send and receive data from the controller U3 and connects to the host computer via the output port USB1. It can transmit the current measurement results to the host computer. The eighth pin of the serial port chip U7 is grounded through capacitor C1, and the fifth pin of the serial port chip U7 is grounded through capacitor C2. The fifth pin of the serial port chip U7 is also connected to an external 5V power supply, which powers the serial port chip U7. Both capacitors C1 and C2 are filter capacitors.

[0060] In the description of this utility model, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0061] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0062] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the present invention.

Claims

1. A portable current detection device, characterized in that, include: The housing (1) contains a power supply unit, a sampling resistor, a control unit and a display unit; The power supply unit is connected to and supplies power to the control unit and the display unit, respectively. The sampling resistor is used to connect to the current to be measured; The control unit is connected to the sampling resistor and is used to obtain the voltage value across the sampling resistor; The display unit is connected to the control unit and is used to display the current value of the current to be measured.

2. The portable current detection device according to claim 1, characterized in that, The control unit includes: The current detection amplifier U2 has its third and fourth pins connected to the sampling resistor R5 to acquire the voltage value across the sampling resistor R5. Voltage follower U1, the third pin of which is connected to the first pin of current sense amplifier U2, is used to obtain the voltage value across the sampling resistor R5.

3. The portable current detection device according to claim 2, characterized in that, The control unit further includes: The controller U3, whose forty-third pin is connected to the first pin of the voltage follower U1, is used to convert the voltage value across the sampling resistor R5 into the current value of the current to be measured.

4. The portable current detection device according to claim 3, characterized in that, The power supply unit includes: A battery management circuit, which is connected to a power source and a lithium battery respectively, is used to transmit the power source voltage to the lithium battery and charge it; A voltage conversion circuit, wherein the input terminal of the voltage conversion circuit is connected to the power supply or the lithium battery, and the output terminal of the voltage conversion circuit is connected to the control unit and the display unit, for converting the voltage of the power supply or the lithium battery into a preset voltage.

5. The portable current detection device according to claim 4, characterized in that, The battery management circuit includes: The system includes a charging manager U6, resistors R11 and R10, a capacitor C11, a charging indicator LED1, and a full charge indicator LED2. The second pin of the charging manager U6 is connected to the first terminal of resistor R11, and the second terminal of resistor R11 is grounded. The fourth pin of the charging manager U6 is connected to the first terminal of capacitor C11, the first terminal of resistor R10, and the power supply. The second terminal of capacitor C11 is grounded. The second terminal of resistor R10 is connected to the positive terminals of both the charging indicator LED1 and the full charge indicator LED2. The negative terminal of the charging indicator LED1 is connected to the seventh pin of the charging manager U6. The negative terminal of the full charge indicator LED2 is connected to the sixth pin of the charging manager U6. The fifth pin of the charging manager U6 is connected to the lithium battery.

6. The portable current detection device according to claim 4, characterized in that, The voltage conversion circuit includes: The system includes resistors R13 and R14, capacitor C13, resistor R8, diode D2, transistor Q1, switch SW1, capacitor C9, capacitor C10, and a switching power supply module U5. The power supply, resistors R13 and R14 are connected sequentially and grounded. The first terminal of capacitor C13 is connected to the second terminal of resistor R13, and the second terminal is grounded. The first terminal of resistor R8 is connected to the power supply, and the second terminal is grounded. The gate of transistor Q1 is connected to the power supply and the first terminal of resistor R13. The drain of transistor Q1 is connected to the lithium battery. The source of transistor Q1 is connected to the cathode of diode D2 and the first terminal of switch SW1. The anode of diode D2 is connected to the first terminal of resistor R13. The second terminal of switch SW1 is connected to the third terminal of switching power supply module U5. The first terminal of switching power supply module U5 is grounded. The first terminal of capacitor C9 is connected to the third terminal of switching power supply module U5. The second terminal of capacitor C9 is grounded. The first terminal of capacitor C10 is connected to the second terminal of switching power supply module U5. The second terminal of capacitor C10 is grounded.

7. The portable current detection device according to claim 6, characterized in that, Also includes: A reference voltage unit is provided, with its input terminal connected to the voltage conversion circuit and its output terminal connected to the controller U3. The reference voltage unit is used to convert the preset voltage output by the voltage conversion circuit into a reference voltage and output it to the controller U3.

8. The portable current detection device according to claim 7, characterized in that, The reference voltage unit includes: The system includes a resistor R3, a capacitor C5, a capacitor C6, a resistor R4, a capacitor C7, and a voltage regulator U4. The first terminal of resistor R3 is connected to the second terminal of the switching power supply module U5. The second terminal of resistor R3 is connected to the first terminals of capacitors C5, C6, and R4, and to the thirteenth pin of the controller U3. The second terminals of capacitors C5 and C6 are grounded. The second terminal of resistor R4 is connected to the first terminal of capacitor C7, and the second terminal of capacitor C7 is grounded. The first and second terminals of voltage regulator U4 are both connected to the second terminal of resistor R4 and the twelfth pin of the controller U3. The third terminal of voltage regulator U4 is grounded.

9. The portable current detection device according to claim 4, characterized in that, The display unit includes: The pin header interface H1 has a first pin grounded, a second pin connected to the voltage conversion circuit, a third pin connected to the thirty-eighth pin of the controller U3, and a fourth pin connected to the thirty-seventh pin of the controller U3. Display screen (2), the display screen (2) is disposed on the housing (1) and connected to the third and fourth pins of the pin header interface H1 respectively, for displaying the current value of the current to be measured.

10. The portable current detection device according to claim 3, characterized in that, Also includes: The serial port chip U7 is connected to the controller U3 at its input terminal and is used to receive the current value of the current to be measured output by the controller U3. The output port USB1 is connected to the output of the serial port chip U7, and is used to transmit the current value of the current to be measured output by the controller U3 to the host computer.

Images