Modularized digital multimeter experimental instrument

Abstract

The utility model discloses a modularized digital multimeter experimental instrument, which comprises a shell (1), a plurality of functional modules capable of being quickly disassembled and connected are arranged in the shell (1), and the functional modules are in circuit connection through conductive plug-ins or quick connection wires; the function module comprises a circuit protection module (2) which comprises a resistance gear protection circuit (21) and a current gear protection circuit (22) and is used for preventing overload or short circuit in the measurement process; the to-be-measured resistor module (3) is provided with a plurality of to-be-measured resistors (31) with different resistance values, and the two ends of each to-be-measured resistor (31) are combined and connected through a quick connection wire; the resistance grade reference module (4) is provided with a reference voltage circuit (41) consisting of a divider resistor and a voltage stabilizing diode and is used for providing reference voltage for resistance measurement; according to the utility model, through the combination of detachable functional modules, free construction and parameter measurement of a circuit are realized, and teaching interactivity and practicability are enhanced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of teaching appliance, especially a modular digital multimeter experimental instrument. BACKGROUND

[0002] Digital electric meter has been widely used in scientific research, industrial field and production and life with its display intuitive, high accuracy, strong resolution, perfect function, stable performance, small volume and easy to carry etc. Digital electric meter working principle is simple, and the product modular design, including self-assembly module, self-connection line etc. Can let students understand and utilize this tool to design the measurement of current, voltage, resistance, pressure, temperature and other physical quantities, thereby improving the students' practical ability and problem solving ability, however, the existing digital electric meter is mostly finished product, for example, the utility model discloses a kind of intelligent volt-ampere characteristic circuit experimental box, it includes experimental box, low voltage power supply, sliding rheostat, test lamp, electronic ammeter etc. in experimental box body, its component is single and fixed, cannot change circuit structure, the function that can be realized is limited and difficult to understand the working principle of component, operability is not strong, cannot satisfy the in-depth understanding of students to circuit and the improvement of hardware construction ability. CONTENT OF UTILITY MODEL

[0003] The utility model discloses a kind of modular digital multimeter experimental instruments, and the utility model is freely built and parameter measurement by the combination of detachable function module, enhance teaching interactivity and practicality.

[0004] The technical scheme of the utility model: a kind of modular digital multimeter experimental instrument, including shell, multiple function modules are detachably connected in shell, and each function module is connected by conducting insert or quick-connection wire;The function module includes:

[0005] Circuit protection module, including resistance grade protection circuit and current grade protection circuit, for preventing overload or short circuit in measurement process;

[0006] To be measured resistance module, multiple different resistance values are provided to the measured resistance, and each measured resistance is connected by quick-connection wire;

[0007] Resistance grade reference module, reference voltage circuit is provided by voltage dividing resistor and zener diode, for providing reference voltage of resistance measurement;

[0008] Voltage dividing and shunt module, including voltage divider circuit and shunt circuit, for voltage and current range expansion;

[0009] The triode module is provided with NPN triode measuring circuit and PNP triode measuring circuit, which is used for testing the static working point and characteristic parameters of triode.

[0010] The diode measuring circuit module is used for detecting the forward conduction voltage drop and reverse characteristic of diode.

[0011] The measuring table module contains digital table head and signal conversion circuit, which is used for displaying the measuring results.

[0012] The voltage reference source reference module and the multimeter grading module are used for switching different measuring positions.

[0013] The AC voltage to DC voltage signal module is used for converting AC signal into DC signal.

[0014] The DC voltage source module and the AC voltage source module are used for providing adjustable DC and AC power respectively.

[0015] The to-be-tested diode module and the to-be-tested triode module provide test interface of external devices.

[0016] In the modular digital multimeter experiment instrument, the resistance grade protection circuit comprises a thermistor PTC1 and an NPN transistor Q1, one end of the thermistor PTC1 is connected with a fast connecting wire, the other end of the thermistor PTC1 is connected with a fast connecting wire or connected with the emitter of the NPN transistor Q1 through a conductive plug, and the collector of the NPN transistor Q1 is connected with a fast connecting wire; the current grade protection circuit comprises a fuse and a bidirectional diode, one end of the fuse is connected with a fast connecting wire, the other end of the fuse is connected with a fast connecting wire or connected with one end of the bidirectional diode through a conductive plug, and one end of the bidirectional diode is connected with a fast connecting wire.

[0017] In the modular digital multimeter experiment instrument, the reference voltage circuit comprises a voltage dividing resistor R and a zener diode ZD1, one end of the voltage dividing resistor R is connected with a fast connecting wire, the other end of the voltage dividing resistor R is connected with a fast connecting wire or connected with the cathode of the zener diode ZD1 through a conductive plug, and the anode of the zener diode ZD1 is connected with a fast connecting wire.

[0018] In the modular digital multimeter experiment instrument, the to-be-tested resistance comprises a reference resistance Rs, a reference resistance Rx, an access resistance R1, an access resistance R2, an access resistance R3, an access resistance R4, an access resistance R5 and an access resistance R6, and each resistance is connected with a fast connecting wire at both ends for arbitrary combination.

[0019] In the modular digital multimeter experiment instrument, the shunt circuit includes a first shunt circuit and a second shunt circuit, and the voltage divider circuit includes a first voltage divider circuit and a second voltage divider circuit; the first shunt circuit includes shunt resistors R7, R8, R9, R10 and R11 connected in series, and the two ends of the series circuit and the connection of the resistors are connected with quick connecting wires; the second shunt circuit includes shunt resistors R12, R13, R14, R15 and R16 connected in series, and the two ends of the series circuit and the connection of the resistors are connected with quick connecting wires; the first voltage divider circuit includes voltage divider resistors R17, R18, R19, R20 and R21 connected in series, and the two ends of the series circuit and the connection of the resistors are connected with quick connecting wires; the second voltage divider circuit includes voltage divider resistors R22, R23, R24, R25 and R26 connected in series, and the two ends of the series circuit and the connection of the resistors are connected with quick connecting wires; and the range resistor circuit includes range resistors R27, R28, R29, R30 and R31 connected in series, and the two ends of the series circuit and the connection of the resistors are connected with quick connecting wires.

[0020] In the modular digital multimeter experiment instrument, the NPN transistor measurement circuit includes a potentiometer RP3, a resistor R37, an NPN transistor, a resistor R38, a resistor R39 and a power tube XNO, the collector of the NPN transistor is connected with one end of the potentiometer RP3 through a conductive plug and connected with a power supply through a quick connecting wire, the base of the NPN transistor is connected with one end of the resistor R37, the other end of the resistor R37 is connected with the other end of the potentiometer RP3, the emitter of the NPN transistor is connected with one end of the resistor R38 and one end of the resistor R39, the other end of the resistor R38 is connected with the power tube XNO, and the other end of the resistor R39 is grounded through a quick connecting wire; and the PNP transistor measurement circuit includes a PNP transistor, a potentiometer RP2, a resistor R40, a resistor R41, a resistor R42 and a power tube XPO, the emitter of the PNP transistor is connected with a power supply through a quick connecting wire, the base of the PNP transistor is connected with one end of the potentiometer RP2, the other end of the potentiometer RP2 is connected with the resistor R40, the collector of the PNP transistor is connected with one end of the resistor R41 and one end of the resistor R42, the other end of the resistor R41 is connected with the power tube XPO, and the other end of the resistor R42 and the other end of the resistor R40 are grounded through quick connecting wires.

[0021] In the modular digital multimeter experiment instrument, the diode measurement circuit module is provided with a diode measurement circuit, which comprises a resistor R43, a resistor R44, a diode D1, a power tube XDA, a power tube XDK and a power tube XDO, one end of the resistor R43 is connected to a power supply through a quick connecting wire, the other end of the resistor R43 is connected to one end of the resistor R44 and the power tube XDA through a quick connecting wire, the other end of the resistor R44 is connected to the power tube XDO, the positive electrode of the diode D1 is connected to the power tube XDA, the negative electrode of the diode D1 is connected to the power tube XDK, and the power tube XDK is grounded through a quick connecting wire.

[0022] In the modular digital multimeter experiment instrument, the AC voltage to DC voltage signal module is provided with an AC to DC circuit, which comprises a voltage input end VIN, a voltage output end VOUT, a signal processing chip U1, resistors R45, R46, R47, R48, an adjusting resistor R49, diodes D2, D3, D4, D5, D6, D7, D8, capacitors C1, C2, C3, C4, C5, C6 and C7, both ends of the resistors R45, R46, R47, R48, the adjusting resistor R49, the diodes D2, D3, D4, D5, D6, D7, D8, the capacitors C1, C2, C3, C4, C5 and C6 are connected to conductive inserts or quick connecting wires, the input end of the signal processing chip U1 is connected to the voltage input end VIN through a combination of quick connecting wires or conductive inserts after being connected to the resistors R45, D2 and D3, the output end of the signal processing chip U1 is connected to the voltage output end VOUT through a combination of quick connecting wires or conductive inserts after being connected to the resistors R46, R47, R48, the adjusting resistor R49, the diodes D4, D5, D6, the capacitors C1, C2, C3, C4 and C5, the power supply end of the signal processing chip U1 is connected to a power supply through a combination of quick connecting wires or conductive inserts after being connected to the diodes D7, D8, the capacitors C6 and C7.

[0023] In the modular digital multimeter experiment instrument, the DC voltage source module is provided with a DC voltage circuit, the DC voltage circuit comprises a DC output end DC, a potentiometer RP1, a resistor R49, a resistor R50, a terminal block U2, a diode D9, a capacitor C8 and a capacitor C9, the potentiometer RP1, the resistor R49, the resistor R50, the terminal block U2, the diode D9, the capacitor C8 and the capacitor C9 are connected with conductive inserts or quick connecting wires at both ends, the negative electrode of the diode D9 is connected with the power supply through the conductive insert, the positive electrode of the diode D9 is connected with the potentiometer RP1, the resistor R49, the resistor R50, the terminal block U2, the capacitor C8 and the capacitor C9 through the combination of the conductive insert and the quick connecting wire and then connected with the DC output end DC; the AC voltage source module is provided with an AC voltage circuit, the AC voltage circuit comprises an AC output end AC, a potentiometer RP4, a resistor R51, a resistor R52, a resistor R53, a resistor R54, a resistor R55, a resistor R56, a resistor R57, a resistor R58, a resistor R59, a capacitor C10, a capacitor C11, a capacitor C12, a capacitor C13, a capacitor C14, a signal processing chip U3, a diode D10, a diode D11, a diode D12, a diode D13 and a terminal block U4, the potentiometer RP4, the resistor R51, the resistor R52, the resistor R53, the resistor R54, the resistor R55, the resistor R56, the resistor R57, the resistor R58, the resistor R59, the capacitor C10, the capacitor C11, the capacitor C12, the capacitor C13, the capacitor C14, the signal processing chip U3, the diode D10, the diode D11, the diode D12, the diode D13, the diode D14 and the terminal block U4 are connected with conductive inserts or quick connecting wires at both ends, the positive electrode of the diode D10 is connected with the negative electrode of the power supply through the conductive insert, the two terminal blocks U4 are connected with the positive electrode of the power supply through the conductive insert, the negative electrode of the diode D10 is connected with the potentiometer RP4, the resistor R51, the resistor R52, the resistor R53, the resistor R54, the resistor R55, the resistor R56, the resistor R57, the resistor R58, the resistor R59, the capacitor C10, the capacitor C11, the capacitor C12, the capacitor C13, the capacitor C14, the signal processing chip U3, the diode D11, the diode D12, the diode D13, the diode D14 and the terminal block U4 through the combination of the conductive insert and the quick connecting wire and then connected with the AC output end AC.

[0024] Compared with the prior art, the utility model has the following beneficial effects:

[0025] 1、The various functional modules of the experimental instrument are connected through conductive plugs or quick-connect wires, and the modules are also connected in combination with quick-connect wires. This design allows students to freely select and combine different modules and components, and to independently build circuits with various parameters and functions. For example, when learning resistance measurement, students can select different resistors to be measured from the resistor module to be measured, and combine them with the resistance base module, the voltage divider and current divider module, and the measurement table module to build a resistance measurement circuit. This allows students to experience the impact of different resistance combinations on measurement results and to gain a deep understanding of resistance measurement principles. During the building process, students need to understand the functions and connection methods of each module, which helps to improve their circuit building skills and practical application ability of circuit principles, greatly enhancing the operability of the experiment and providing students with rich opportunities for practical learning.

[0026] 2、The experimental instrument integrates multiple functional modules with different functions, covering various aspects from circuit protection to measurement of various physical quantities. Through the combination of different modules, measurement of various parameters such as current, voltage, resistance, diode, and transistor performance can be achieved. For example, when measuring current, the current divider circuit in the voltage divider and current divider module can be used in combination with the measurement table module to measure different sizes of current. When measuring voltage, the voltage divider circuit and the measurement table module can be used to accurately measure AC and DC voltages in different ranges. For diodes and transistors, the corresponding measurement circuits and resistors to be measured can be used to comprehensively detect their performance parameters. The multi-functional design meets the needs of digital meter parameter measurement under various working conditions, allowing students to complete various experimental projects on one experimental instrument, broadening their knowledge and practical field.

[0027] 3、The modules of the utility information are connected in a quick-release manner, which has independence. When a fault occurs during the experiment, it is easy to quickly locate and troubleshoot the problem. For example, if the measurement result is abnormal, students can quickly determine whether it is due to damage to internal components of a module or problems in the connection between modules based on the circuit connection. For damaged modules, they can be easily removed for individual inspection and repair without affecting the normal use of other modules. This modular design reduces the difficulty of troubleshooting and maintenance costs, improves the efficiency and reliability of the experimental instrument, and also helps to develop students' problem analysis and problem-solving skills.

[0028] 4、The function module of the experiment instrument is clear in division, each function module has definite function and corresponding circuit structure, for example, the resistance grade reference module provides stable reference voltage, students can visually see the circuit composition and working principle thereof, the AC voltage to DC voltage signal module decomposes the complex AC voltage conversion process into specific circuit steps, students can clearly understand how the signal is converted through various components and processing links, the clear structure design enables students to systematically learn the circuit principle of the digital multimeter, gradually masters the working mechanism from the part to the whole, which helps students to establish complete circuit knowledge system and deepen the understanding and memory of the circuit principle. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is the structure schematic diagram of the utility model;

[0030] Figure 2 It is the structure schematic diagram of the circuit protection module of the utility model;

[0031] Figure 3 It is the structure schematic diagram of the circuit protection module of the utility model;

[0032] Figure 4 It is the structure schematic diagram of the triode module of the utility model;

[0033] Figure 5 It is the structure schematic diagram of the measurement table module of the utility model;

[0034] Figure 6 It is the structure schematic diagram of the multimeter grading module of the utility model;

[0035] Figure 7 It is the structure schematic diagram of the AC voltage to DC voltage signal module of the utility model;

[0036] Figure 8 It is the structure schematic diagram of the DC voltage source module of the utility model;

[0037] Figure 9 It is the structure schematic diagram of the to-be-measured diode module of the utility model.

[0038] The marks in the drawing are: 1, shell; 2, circuit protection module; 21, resistance grade protection circuit; 22, current grade protection circuit; 3, resistance module to be measured; 31, resistance to be measured; 4, resistance grade reference module; 41, reference voltage circuit; 5, voltage divider and current divider module; 51, first voltage divider circuit; 52, second voltage divider circuit; 53, first current divider circuit; 54, second current divider circuit; 55, resistance grading circuit; 6, triode module; 61, NPN triode measurement circuit; 62, PNP triode measurement circuit; 7, diode measurement circuit module; 71, diode measurement circuit; 8, measurement table module; 9, voltage reference source reference module; 10, universal table grading module; 11, AC voltage to DC voltage signal module; 111, AC to DC circuit; 12, DC voltage source module; 121, DC voltage circuit; 13, AC voltage source module; 131, AC voltage circuit; 14, diode module to be measured; 15, triode module to be measured. DETAILED DESCRIPTION

[0039] The utility model will be further described below in combination with the drawings and examples, but not as the basis for limiting the utility model.

[0040] Example: a kind of modular digital multimeter experimental instrument, as shown in the drawing Figure 1As shown, the device includes a housing 1, made of powder-coated steel plate with ventilation holes on the left and right sides, and surrounded by blue ABS molded edges. It can hold nine experimental modules, has a power interface on the side, and is covered with an acrylic protective panel on the top. Inside housing 1, quick-release connections are made of a circuit protection module 2, a resistor under test module 3, a resistance range reference module 4, a voltage divider and shunt module 5, a transistor module 6, a diode measurement circuit module 7, a measuring meter module 8, a voltage reference source module 9, a multimeter range module 10, an AC voltage to DC voltage signal module 11, a DC voltage source module 12, an AC voltage source module 13, a diode under test module 14, and a transistor under test module 15. Each module is quickly connected via magnetic blocks at the bottom and magnetic blocks inside the housing, and arranged sequentially. Components within the modules are connected via conductive plugs or quick-connect wires. Modules are connected via quick-connect wire combinations. The conductive plugs of the banana plugs are inserted into the corresponding sockets to connect the circuits of the corresponding two components. Quick-connect wires with banana plugs at both ends are inserted into the corresponding sockets to achieve distance control. The connection between two components is as follows: The circuit protection module 2 is equipped with a resistance range protection circuit 21 and a current range protection circuit 22; The resistor under test module 3 is equipped with multiple resistors under test 31; The resistance range reference module 4 is equipped with a reference voltage circuit 41; The voltage divider and shunt module 5 is equipped with a first voltage divider circuit 51, a second voltage divider circuit 52, a first shunt circuit 53, a second shunt circuit 54, and a range resistor circuit 55; The transistor module 6 is equipped with an NPN transistor measurement circuit 61 and a PNP transistor measurement circuit 62; The diode measurement circuit module 7 is equipped with a diode measurement circuit 71; The AC voltage to DC voltage signal module 11 is equipped with an AC to DC circuit 111; The DC voltage source module 12 is equipped with a DC voltage circuit 121; The AC voltage source module 13 is equipped with an AC voltage circuit 131; As shown in the appendix Figure 5 As shown, the measuring module uses a 7107 meter head and has an internal voltage reference chip. It converts the input analog signal into a digital signal and presents it intuitively in digital form. For example, when measuring parameters such as voltage, current, and resistance, it can clearly display the corresponding values, as shown in the attached diagram. Figure 6 As shown, the multimeter range switching module performs corresponding measurements by switching between different resistance ranges, different current ranges, and different voltage ranges in conjunction with the measuring meter module; as attached... Figure 9 As shown, the diode under test module and the transistor under test module provide test interfaces for diodes and transistors, making it easy to connect to test circuits to detect their performance parameters.

[0041] As attached Figure 2As shown, the resistance grade protection circuit 21 includes a thermistor PTC1 and an NPN transistor Q1, one end of the thermistor PTC1 is connected to the fast connecting wire, the other end of the thermistor PTC1 is connected to the fast connecting wire or connected to the emitter of the NPN transistor Q1 through the conductive plug, the collector of the NPN transistor Q1 is connected to the fast connecting wire; the current grade protection circuit includes a fuse and a bidirectional diode, one end of the fuse is connected to the fast connecting wire, the other end of the fuse is connected to the fast connecting wire or connected to one end of the bidirectional diode through the conductive plug, one end of the bidirectional diode is connected to the fast connecting wire, for circuit protection in different measurement modes.

[0042] As shown in the accompanying drawings Figure 2 As shown, the reference voltage circuit 41 includes a voltage dividing resistor R and a zener diode ZD1, one end of the voltage dividing resistor R is connected to the fast connecting wire, the other end of the voltage dividing resistor R is connected to the fast connecting wire or connected to the cathode of the zener diode ZD1 through the conductive plug, the anode of the zener diode ZD1 is connected to the fast connecting wire, in resistance measurement, the reference voltage is used as a reference quantity, compared or operated with parameters such as voltage drop on the resistance to be measured, and then the resistance value of the resistance to be measured is calculated through circuit principle.

[0043] As shown in the accompanying drawings Figure 2 As shown, the resistance to be measured 31 includes a reference resistance Rs, a reference resistance Rx, an access resistance R1 with a resistance of 100Ω, an access resistance R2 with a resistance of 470Ω, an access resistance R3 with a resistance of 10KΩ, an access resistance R4 with a resistance of 1kΩ, an access resistance R5 with a resistance of 47KΩ, and an access resistance R6 with a resistance of 4.7KΩ, students can select different resistances to be measured from the resistance to be measured module for combination, cooperate with the resistance grade reference module, the voltage dividing and shunt module and the measurement table module, build a resistance measurement circuit, experience the influence of different resistance value combinations on the measurement results, and deeply understand the resistance measurement principle;

[0044] As shown in the accompanying drawings Figure 3The first shunt circuit 53 includes 900Ω shunt resistor R7, 90Ω shunt resistor R8, 9Ω shunt resistor R9, 0.9Ω shunt resistor R10 and 0.1Ω shunt resistor R11 connected in series, and the fast connecting wires are connected at both ends of the series circuit and the connection of the resistors; the second shunt circuit 54 includes 1KΩ shunt resistor R12, 100Ω shunt resistor R13, 10Ω shunt resistor R14, 1Ω shunt resistor R15 and 0.1Ω shunt resistor R16 connected in series, and the fast connecting wires are connected at both ends of the series circuit and the connection of the resistors. When measuring current, the shunt uses the parallel resistance shunt principle to shunt large current, so that the current passing through the ammeter module is within its range, thereby realizing the measurement of large current; the first voltage divider circuit 51 includes 9MΩ voltage divider resistor R17, 900KΩ voltage divider resistor R18, 90KΩ voltage divider resistor R19, 9KΩ voltage divider resistor R20 and 1KΩ voltage divider resistor R21 connected in series, and the fast connecting wires are connected at both ends of the series circuit and the connection of the resistors; the second voltage divider circuit 52 includes 10MΩ voltage divider resistor R22, 1MΩ voltage divider resistor R23, 99KΩ voltage divider resistor R24, 9KΩ voltage divider resistor R25 and 1KΩ voltage divider resistor R26 connected in series, and the fast connecting wires are connected at both ends of the series circuit and the connection of the resistors. When measuring voltage, according to the series resistance voltage division principle, the input high voltage is divided according to the resistance ratio, and a low voltage suitable for the ammeter module to measure is output, so as to accurately measure different ranges of voltage values, so that the measuring equipment can safely and accurately measure; the shunt resistor circuit 55 includes shunt resistor R27, shunt resistor R28, shunt resistor R29, shunt resistor R30 and shunt resistor R31 connected in series, and the fast connecting wires are connected at both ends of the series circuit and the connection of the resistors. In the resistance measurement circuit, the shunt resistor cooperates with other circuit elements to switch different resistance measurement positions. Different shunt resistors correspond to different measurement ranges. By selecting appropriate shunt resistors, resistors in the range from low resistance to high resistance can be measured, expanding the range and accuracy of resistance measurement.

[0045] As shown in the accompanying drawings Figure 4As shown, the NPN transistor measurement circuit 61 includes potentiometer RP3, resistor R37, NPN transistor, resistor R38, resistor R39 and power tube XNO, the collector of the NPN transistor is connected to one end of potentiometer RP3 through a conductive plug and to the power supply through a quick-wired conductor, the base of the NPN transistor is connected to one end of resistor R37, the other end of resistor R37 is connected to the other end of potentiometer RP3, the emitter of the NPN transistor is connected to one end of resistor R38 and one end of resistor R39, the other end of resistor R38 is connected to power tube XNO, and the other end of resistor R39 is grounded through a quick-wired conductor. By providing a suitable bias voltage, the NPN transistor works in a specific region, and by measuring the current and voltage relationship between the poles, it is determined that it is in an amplification, saturation, cutoff and other working states. The PNP transistor measurement circuit 62 includes PNP transistor, potentiometer RP2, resistor R40, resistor R41, resistor R42 and power tube XPO, the emitter of the PNP transistor is connected to the power supply through a quick-wired conductor, the base of the PNP transistor is connected to one end of potentiometer RP2, the other end of potentiometer RP2 is connected to resistor R40, the collector of the PNP transistor is connected to one end of resistor R41 and one end of resistor R42, the other end of resistor R41 is connected to power tube XPO, and the other end of resistor R42 and the other end of resistor R40 are grounded through a quick-wired conductor. Similar to the NPN transistor measurement circuit, a reasonable circuit design is provided for the PNP transistor to provide a suitable bias to determine its working state.

[0046] As shown in the accompanying drawings, Figure 4 As shown, the diode measurement circuit 71 includes resistor R43, resistor R44, diode D1, power tube XDA, power tube XDK and power tube XDO, one end of resistor R43 is connected to the power supply through a quick-wired conductor, the other end of resistor R43 is connected to one end of resistor R44 and power tube XDA through a quick-wired conductor, the other end of resistor R44 is connected to power tube XDO, the positive electrode of diode D1 is connected to power tube XDA, the negative electrode of diode D1 is connected to power tube XDK, and power tube XDK is grounded through a quick-wired conductor. By utilizing the one-way conduction characteristic of the diode, by measuring the voltage across the diode and the current flowing through it, etc., the forward conduction voltage drop and other performance parameters can be calculated to evaluate the quality and performance of the diode.

[0047] As shown in the accompanying drawings, Figure 7As shown, the AC-DC circuit 111 includes a voltage input terminal VIN, a voltage output terminal VOUT, a signal processing chip U1, a resistor R45, a resistor R46, a resistor R47, a resistor R48, a regulating resistor R49, a diode D2, a diode D3, a diode D4, a diode D5, a diode D6, a diode D7, a diode D8, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6 and a capacitor C7, both ends of the resistor R45, the resistor R46, the resistor R47, the resistor R48, the regulating resistor R49, the diode D2, the diode D3, the diode D4, the diode D5, the diode D6, the diode D7, the diode D8, the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C4, the capacitor C5 and the capacitor C6 are connected with a conductive plug or a quick-connect wire, the input terminal of the signal processing chip U1 is connected with the voltage input terminal VIN through the quick-connect wire or the conductive plug in combination with the resistor R45, the diode D2 and the diode D3, the output terminal of the signal processing chip U1 is connected with the voltage output terminal VOUT through the quick-connect wire or the conductive plug in combination with the resistor R46, the resistor R47, the resistor R48, the regulating resistor R49, the diode D4, the diode D5, the diode D6, the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C4 and the capacitor C5; the power supply terminal of the signal processing chip U1 is connected with the power supply through the quick-connect wire or the conductive plug in combination with the diode D7, the diode D8, the capacitor C6 and the capacitor C7, and the input AC voltage signal is converted into different DC voltage signals for output.

[0048] As shown in the accompanying drawings Figure 8As shown, the direct current circuit 121 includes a direct current output end DC, a potentiometer RP1, a resistor R49, a resistor R50, a terminal block U2, a diode D9, a capacitor C8 and a capacitor C9, both ends of the potentiometer RP1, the resistor R49, the resistor R50, the terminal block U2, the diode D9, the capacitor C8 and the capacitor C9 are connected with a conductive plug or a quick connection wire, the negative electrode of the diode D9 is connected with a power supply through the conductive plug, the positive electrode of the diode D9 is connected with the potentiometer RP1, the resistor R49, the resistor R50, the terminal block U2, the capacitor C8 and the capacitor C9 through the combination of the conductive plug and the quick connection wire, and then connected with the direct current output end DC, and a direct current with corresponding parameters is generated through the combination of the components as a power supply; the alternating current circuit 131 includes an alternating current output end AC, a potentiometer RP4, a resistor R51, a resistor R52, a resistor R53, a resistor R54, a resistor R55, a resistor R56, a resistor R57, a resistor R58, a resistor R59, a capacitor C10, a capacitor C11, a capacitor C12, a capacitor C13, a capacitor C14, a signal processing chip U3, a diode D10, a diode D11, a diode D12, a diode D13, and a terminal block U4, both ends of the potentiometer RP4, the resistor R51, the resistor R52, the resistor R53, the resistor R54, the resistor R55, the resistor R56, the resistor R57, the resistor R58, the resistor R59, the capacitor C10, the capacitor C11, the capacitor C12, the capacitor C13, the capacitor C14, the signal processing chip U3, the diode D10, the diode D11, the diode D12, the diode D13, the diode D14, and the terminal block U4 are connected with a conductive plug or a quick connection wire, the positive electrode of the diode D10 is connected with a negative electrode of a power supply through the conductive plug, the terminal block U4 is connected with a positive electrode of the power supply through the conductive plug, the negative electrode of the diode D10 is connected with the potentiometer RP4, the resistor R51, the resistor R52, the resistor R53, the resistor R54, the resistor R55, the resistor R56, the resistor R57, the resistor R58, the resistor R59, the capacitor C10, the capacitor C11, the capacitor C12, the capacitor C13, the capacitor C14, the signal processing chip U3, the diode D11, the diode D12, the diode D13, the diode D14, and the terminal block U4 through the combination of the conductive plug and the quick connection wire, and then connected with the alternating current output end AC, and an alternating current with corresponding parameters is generated through the combination of the components as a power supply.

[0049] In summary, each functional module is connected through a conductive plug or a quick connection wire, and the modules are also connected in combination with quick connection wires, students can freely select and combine different modules and components, and independently build circuits with multiple parameters and functions, in the process of building, students need to understand the function and connection mode of each module, which helps to improve their circuit building skills and practical application ability of circuit principle, greatly enhances the operability of the experiment, integrates multiple functional modules with different functions, covers various links from circuit protection to measurement of various physical quantities, and through combination of different modules, measurement of multiple parameters such as current, voltage, resistance, diode and triode performance can be realized, each module adopts a quick release connection mode, for damaged modules, they can be directly disassembled for individual inspection and repair, without affecting the normal use of other modules, this modular design reduces the difficulty of troubleshooting and maintenance cost, and improves the use efficiency and reliability of the experimental instrument.

[0050] The above embodiments only express the implementation of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the application patent, and in the present embodiment, up, down, left, right, front, back only represent their relative positions and not their absolute positions. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.

Claims

1. A modular digital multimeter lab instrument, characterized by: The utility model relates to a multi-functional resistance measuring device, comprising a shell (1), a plurality of functional modules are arranged in the shell (1), and the functional modules are connected through conductive plugs or quick connection wires; the functional modules comprise: a circuit protection module (2) comprising a resistance protection circuit (21) and a current protection circuit (22) for preventing overload or short circuit during measurement; a resistance to be measured module (3) comprising a plurality of resistors to be measured (31) with different resistance values, and the resistors to be measured (31) are connected through quick connection wires; a resistance grade reference module (4) comprising a reference voltage circuit (41) composed of a voltage dividing resistor and a voltage stabilizing diode for providing reference voltage for resistance measurement; a voltage dividing and shunt module (5) comprising a resistance grading circuit (55), a voltage divider circuit and a shunt circuit for range expansion of voltage and current; a transistor module (6) comprising an NPN transistor measurement circuit (61) and a PNP transistor measurement circuit (62) for testing the static operating point and characteristic parameters of transistors; a diode measurement circuit module (7) for detecting the forward conduction voltage drop and reverse characteristics of diodes; a measurement table module (8) comprising a digital meter head and a signal conversion circuit for displaying measurement results; a voltage reference source reference module (9) and a multimeter grading module (10) for switching different measurement grades; an AC voltage to DC voltage signal module (11) for converting AC signals into DC signals; a DC voltage source module (12) and an AC voltage source module (13) for providing adjustable DC and AC power sources, respectively; a diode to be measured module (14) and a transistor to be measured module (15) for providing test interfaces of external devices.

2. The modular digital multimeter lab kit of claim 1, wherein: The resistance protection circuit (21) comprises a thermistor PTC1 and an NPN transistor Q1, one end of the thermistor PTC1 is connected to a quick connection wire, the other end of the thermistor PTC1 is connected to a quick connection wire or connected to the emitter of the NPN transistor Q1 through a conductive plug, and the collector of the NPN transistor Q1 is connected to a quick connection wire; the current protection circuit (22) comprises a fuse and a bidirectional diode, one end of the fuse is connected to a quick connection wire, the other end of the fuse is connected to a quick connection wire or connected to one end of the bidirectional diode through a conductive plug, and one end of the bidirectional diode is connected to a quick connection wire.

3. The modular digital multimeter lab kit of claim 1, wherein: The reference voltage circuit (41) comprises a voltage dividing resistor R and a voltage stabilizing diode ZD1, one end of the voltage dividing resistor R is connected to a quick connection wire, the other end of the voltage dividing resistor R is connected to a quick connection wire or connected to the cathode of the voltage stabilizing diode ZD1 through a conductive plug, and the anode of the voltage stabilizing diode ZD1 is connected to a quick connection wire.

4. The modular digital multimeter lab kit of claim 1, wherein: The resistors to be measured (31) comprise a reference resistor Rs, a reference resistor Rx, access resistors R1, R2, R3, R4, R5 and R6, and the resistors are connected to quick connection wires for arbitrary combination.

5. The modular digital multimeter lab kit of claim 1, wherein: The shunt circuit comprises a first shunt circuit (53) and a second shunt circuit (54), the voltage divider circuit comprises a first voltage divider circuit (51) and a second voltage divider circuit (52); the first shunt circuit (53) comprises shunt resistors R7, R8, R9, R10 and R11 connected in series, and the two ends of the series circuit and the connection of the resistors are connected with quick connecting wires; the second shunt circuit (54) comprises shunt resistors R12, R13, R14, R15 and R16 connected in series, and the two ends of the series circuit and the connection of the resistors are connected with quick connecting wires; the first voltage divider circuit (51) comprises voltage divider resistors R17, R18, R19, R20 and R21 connected in series, and the two ends of the series circuit and the connection of the resistors are connected with quick connecting wires; the second voltage divider circuit (52) comprises voltage divider resistors R22, R23, R24, R25 and R26 connected in series, and the two ends of the series circuit and the connection of the resistors are connected with quick connecting wires; the resistance grading circuit (55) comprises resistance grading resistors R27, R28, R29, R30 and R31 connected in series, and the two ends of the series circuit and the connection of the resistors are connected with quick connecting wires.

6. The modular digital multimeter lab kit of claim 1, wherein: The NPN transistor measurement circuit (61) comprises a potentiometer RP3, a resistor R37, an NPN transistor, a resistor R38, a resistor R39 and a power tube XNO, the collector of the NPN transistor is connected with one end of the potentiometer RP3 through a conductive plug and connected with a power supply through a quick connecting wire, the base of the NPN transistor is connected with one end of the resistor R37, the other end of the resistor R37 is connected with the other end of the potentiometer RP3, the emitter of the NPN transistor is connected with one end of the resistor R38 and one end of the resistor R39, the other end of the resistor R38 is connected with the power tube XNO, and the other end of the resistor R39 is grounded through a quick connecting wire; the PNP transistor measurement circuit (62) comprises a PNP transistor, a potentiometer RP2, a resistor R40, a resistor R41, a resistor R42 and a power tube XPO, the emitter of the PNP transistor is connected with a power supply through a quick connecting wire, the base of the PNP transistor is connected with one end of the potentiometer RP2, the other end of the potentiometer RP2 is connected with the resistor R40, the collector of the PNP transistor is connected with one end of the resistor R41 and one end of the resistor R42, the other end of the resistor R41 is connected with the power tube XPO, and the other end of the resistor R42 and the other end of the resistor R40 are grounded through a quick connecting wire.

7. The modular digital multimeter lab kit of claim 1, wherein: The diode measurement circuit module (7) is provided with a diode measurement circuit (71), which comprises a resistor R43, a resistor R44, a diode D1, a power tube XDA, a power tube XDK and a power tube XDO. One end of the resistor R43 is connected to a power supply via a quick connecting wire, the other end of the resistor R43 is connected to one end of the resistor R44 and the power tube XDA via a quick connecting wire, the other end of the resistor R44 is connected to the power tube XDO, the positive electrode of the diode D1 is connected to the power tube XDA, the negative electrode of the diode D1 is connected to the power tube XDK, and the power tube XDK is grounded via a quick connecting wire.

8. The modular digital multimeter lab kit of claim 1, wherein: The AC-to-DC voltage signal module (11) is provided with an AC-to-DC circuit (111), which comprises a voltage input end VIN, a voltage output end VOUT, a signal processing chip U1, a resistor R45, a resistor R46, a resistor R47, a resistor R48, an adjusting resistor R49, a diode D2, a diode D3, a diode D4, a diode D5, a diode D6, a diode D7, a diode D8, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6 and a capacitor C7. The two ends of the resistor R45, the resistor R46, the resistor R47, the resistor R48, the adjusting resistor R49, the diode D2, the diode D3, the diode D4, the diode D5, the diode D6, the diode D7, the diode D8, the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C4, the capacitor C5 and the capacitor C6 are connected to a conductive plug or a quick connecting wire. The input end of the signal processing chip U1 is connected to the voltage input end VIN via a quick connecting wire or a conductive plug in combination with the resistor R45, the diode D2 and the diode D3. The output end of the signal processing chip U1 is connected to the voltage output end VOUT via a quick connecting wire or a conductive plug in combination with the resistor R46, the resistor R47, the resistor R48, the adjusting resistor R49, the diode D4, the diode D5, the diode D6, the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C4 and the capacitor C5. The power supply end of the signal processing chip U1 is connected to a power supply via a quick connecting wire or a conductive plug in combination with the diode D7, the diode D8, the capacitor C6 and the capacitor C7.

9. The modular digital multimeter lab kit of claim 1, wherein: The direct current voltage source module (12) is provided with a direct current voltage circuit (121), the direct current voltage circuit (121) includes a direct current output end DC, a potentiometer RP1, a resistor R49, a resistor R50, a terminal block U2, a diode D9, a capacitor C8 and a capacitor C9, the both ends of the potentiometer RP1, the resistor R49, the resistor R50, the terminal block U2, the diode D9, the capacitor C8 and the capacitor C9 are connected with a conductive plug or a quick connection wire, the negative pole of the diode D9 is connected with a power supply through the conductive plug, the positive pole of the diode D9 is connected with the potentiometer RP1, the resistor R49, the resistor R50, the terminal block U2, the capacitor C8 and the capacitor C9 through the combination of the conductive plug and the quick connection wire and then connected with the direct current output end DC; the alternating current voltage source module (13) is provided with an alternating current voltage circuit (131), the alternating current voltage circuit (131) includes an alternating current output end AC, a potentiometer RP4, a resistor R51, a resistor R52, a resistor R53, a resistor R54, a resistor R55, a resistor R56, a resistor R57, a resistor R58, a resistor R59, a capacitor C10, a capacitor C11, a capacitor C12, a capacitor C13, a capacitor C14, a signal processing chip U3, a diode D10, a diode D11, a diode D12, a diode D13 and a terminal block U4, the both ends of the potentiometer RP4, the resistor R51, the resistor R52, the resistor R53, the resistor R54, the resistor R55, the resistor R56, the resistor R57, the resistor R58, the resistor R59, the capacitor C10, the capacitor C11, the capacitor C12, the capacitor C13, the capacitor C14, the signal processing chip U3, the diode D10, the diode D11, the diode D12, the diode D13, the diode D14 and the terminal block U4 are connected with a conductive plug or a quick connection wire, the positive pole of the diode D10 is connected with a power supply negative pole through the conductive plug, the terminal block U4 is connected with a power supply positive pole through the conductive plug, the negative pole of the diode D10 is connected with the potentiometer RP4, the resistor R51, the resistor R52, the resistor R53, the resistor R54, the resistor R55, the resistor R56, the resistor R57, the resistor R58, the resistor R59, the capacitor C10, the capacitor C11, the capacitor C12, the capacitor C13, the capacitor C14, the signal processing chip U3, the diode D11, the diode D12, the diode D13, the diode D14 and the terminal block U4 through the combination of the conductive plug and the quick connection wire and then connected with the alternating current output end AC.

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