Universal meter

Abstract

The utility model relates to the technical field of electronic measurement, in particular to a universal meter. The capacitance / inductance test hole is arranged on the universal meter body of the universal meter, and the to-be-tested capacitor / inductor is directly inserted into the capacitance / inductance test hole to be directly connected with the capacitance / inductance test circuit, so that the path between the capacitance / inductor and the capacitance / inductance test circuit is reduced, the test error is obviously reduced, and the test efficiency is improved. The influence of a long meter pen line required by a traditional universal meter on a test result is effectively avoided, and the measurement accuracy is improved. Besides, capacitance / inductance test holes can be integrated into part of the triode test holes, and the triode test or capacitance / inductance test can be realized through a switching circuit of the capacitance / inductance test circuit and the triode test circuit, so that the test efficiency is improved by multiplexing part of the existing triode test holes. The manufacturing cost of the universal meter is reduced while accurate capacitance / inductance measurement is realized, and the universal meter is easier to popularize.

Description

Technical Field

[0001] This application relates to the field of electronic measurement technology, and particularly relates to a multimeter. Background Art

[0002] In the field of electronic measurement technology, a multimeter is a commonly used measurement tool. It can be used to measure the parameters of various electronic components, such as resistance, capacitance, inductance, etc. However, the measurement of capacitance / inductance by a common multimeter is completed through a long test lead. The long test lead of the multimeter generally has a length of about 1 meter. This causes the long test lead to easily couple with the spatial electric field and have a large parasitic resistance. When measuring capacitance or inductance, the common multimeter uses the long test lead to contact the component to be measured. Affected by the spatial electric field or parasitic resistance of the long test lead, the measurement result has an error. Summary of the Invention

[0003] This application provides a multimeter to solve the technical problem that the inaccurate measurement of capacitance or inductance by the multimeter caused by the spatial electric field or parasitic resistance existing in the long test lead.

[0004] To achieve the above object, this application provides a multimeter, including:

[0005] A multimeter body and a capacitance / inductance test unit;

[0006] The capacitance / inductance test unit includes: a capacitance / inductance test hole, a capacitance / inductance test switch, and a capacitance / inductance test circuit;

[0007] The capacitance / inductance test hole is arranged on the surface of the multimeter body, and the capacitance / inductance is connected to the capacitance / inductance test circuit through the capacitance / inductance test hole;

[0008] The capacitance / inductance test switch is arranged on the surface of the multimeter body and is used to control whether the capacitance / inductance test circuit works;

[0009] The capacitance / inductance test circuit is arranged inside the multimeter body;

[0010] The capacitance / inductance test hole and the capacitance / inductance test switch are both connected to the capacitance / inductance test circuit.

[0011] Optionally, the multimeter body has a function switch knob, and the capacitance / inductance test switch is integrated in the function switch knob of the multimeter body.

[0012] Optionally, one end and the other end of the capacitance / inductance test switch are both connected to the capacitance / inductance test circuit, such that the capacitance / inductance test switch is in series with the capacitance / inductance test circuit; one side and the other side of the capacitance / inductance test hole are both connected to the capacitance / inductance test circuit, such that the capacitance / inductance test hole, the capacitance / inductance test switch, and the capacitance / inductance test circuit are in series with each other.

[0013] Optionally, one end of the capacitance / inductance test switch is connected to the capacitance / inductance test circuit, the other end of the capacitance / inductance test switch is connected to one side of the capacitance / inductance test hole, and the other side of the capacitance / inductance test hole is connected to the capacitance / inductance test circuit, such that the capacitance / inductance test switch, the capacitance / inductance test hole, and the capacitance / inductance test circuit are in series with each other.

[0014] Optionally, the multimeter further includes: a triode test hole and a triode test circuit; the capacitance / inductance test hole is integrated into a partial test hole of the triode test hole.

[0015] Optionally, it further includes: a switching circuit for the capacitance / inductance test circuit and the triode test circuit, and the switching circuit includes first to fourth switches; a first end of the triode test circuit is connected to one end of the first switch, the other end of the first switch is connected to the second switch, the other end of the second switch is connected to a first end of the capacitance / inductance test circuit, a second end of the triode test circuit is connected to one end of the third switch, the other end of the third switch is connected to one end of the fourth switch, the other end of the fourth switch is connected to a second end of the capacitance / inductance test circuit, the triode test hole is arranged between the other end of the first switch and one end of the second switch, and the capacitance / inductance test hole is arranged between the other end of the third switch and one end of the fourth switch.

[0016] Optionally, it further includes: a display screen, and the display screen is arranged on the surface of the multimeter body for displaying the value of capacitance / inductance.

[0017] Optionally, it further includes: an indicator light, and the indicator light is arranged on the surface of the multimeter body for indicating the on / off status of the capacitance / inductance test circuit.

[0018] Optionally, it further includes: a sound generator; the sound generator is arranged on the surface of the multimeter body for voice reporting and prompting.

[0019] In summary, the advantages and beneficial effects of the present application are as follows:

[0020] The present utility model provides a multimeter, comprising: a multimeter body, a capacitance / inductance test circuit, a capacitance / inductance test hole, and a capacitance / inductance test changeover switch; the capacitance / inductance test circuit is disposed inside the multimeter body; the capacitance / inductance test hole is disposed on the surface of the multimeter body, and the capacitance / inductance is connected to the capacitance / inductance test circuit through the test hole; the capacitance / inductance test changeover switch is disposed on the surface of the multimeter body and is used to control whether the capacitance / inductance test circuit operates; both the capacitance / inductance test hole and the capacitance / inductance test changeover switch are connected to the capacitance / inductance test circuit.

[0021] The capacitance / inductance test hole is disposed on the multimeter body of the multimeter, and the capacitance / inductance to be measured is directly inserted into the capacitance / inductance test hole through the capacitance / inductance test hole on the multimeter body. Since the capacitance / inductance test hole is directly connected to the capacitance / inductance test circuit, the path between the capacitance / inductance and the capacitance / inductance test circuit is reduced, thereby significantly reducing the test error and effectively avoiding the influence of the traditional multimeter on the test result through a long test lead wire, and improving the measurement accuracy.

[0022] In addition, the capacitance / inductance test hole is integrated into the triode test hole, and a switching circuit for the capacitance / inductance test circuit and the triode test circuit is added to realize the selectable test of the triode or the capacitance / inductance. In this way, without re-setting the capacitance / inductance test hole on the multimeter body of the multimeter, and only by reusing part of the test holes of the existing triode test hole, the accurate measurement of the capacitance / inductance is realized, and at the same time, the manufacturing cost of the multimeter is reduced, and it is easier to promote.

[0023] Moreover, through the designed switching circuit for the capacitance / inductance test circuit and the triode test circuit, when in use, only by selecting different gears on the dial, different test holes can be conveniently connected to the corresponding test circuits, and the user operation is very simple, and the user experience is also improved. Description of the Drawings

[0024] Figure 1 is a schematic diagram of a multimeter in this embodiment;

[0025] Figure 2 is a schematic diagram showing that the capacitance / inductance test hole and the capacitance / inductance test changeover switch of a multimeter in this embodiment are both connected to the capacitance / inductance test circuit;

[0026] Figure 3 is a schematic diagram showing that the capacitance / inductance test hole and the capacitance / inductance test changeover switch of a multimeter in other embodiments are both connected to the capacitance / inductance test circuit;

[0027] Figure 4 Schematic diagram of a capacitance / inductance test circuit for a multimeter in this embodiment;

[0028] Figure 5 Schematic diagram of a multimeter in other embodiments;

[0029] Figure 6 Schematic diagram of a switching circuit between a capacitance / inductance test circuit and a triode test circuit for a multimeter in other embodiments. Specific embodiments

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] The terms "first", "second", etc. in the description and claims of this application are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of this application can be implemented in an order different from those illustrated or described herein, and the objects distinguished by "first", "second", etc. are usually of the same category, and the number of objects is not limited. For example, the first object can be one or multiple. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / " generally means an "or" relationship between the associated objects before and after. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0032] The present invention provides a multimeter, as Figure 1 shown, including:

[0033] Multimeter body 1, capacitance / inductance test unit 2;

[0034] The capacitance / inductance test unit 2 includes: capacitance / inductance test holes 21, capacitance / inductance test switch 23, capacitance / inductance test circuit 22;

[0035] The capacitance / inductance test holes 21 are arranged on the surface of the multimeter body 1, and capacitance / inductance is connected to the capacitance / inductance test circuit 22 through the capacitance / inductance test holes 21;

[0036] The capacitance / inductance test switch 23 is disposed on the surface of the multimeter body 1 and is used to control whether the capacitance / inductance test circuit 22 operates;

[0037] The capacitance / inductance test circuit 22 is disposed inside the multimeter body 1;

[0038] Both the capacitance / inductance test hole 21 and the capacitance / inductance test switch 23 are connected to the capacitance / inductance test circuit 22.

[0039] In this embodiment, the multimeter body 1 has a function switching switch knob, and the capacitance / inductance test switch 23 is integrated into the function switching switch knob of the multimeter body 1.

[0040] In other embodiments, the capacitance / inductance test switch may adopt devices such as analog switches and relays that can achieve switching.

[0041] In this embodiment, as Figure 2 shown, one end and the other end of the capacitance / inductance test switch 23 are both connected to the capacitance / inductance test circuit 22, so that the capacitance / inductance test switch 23 is in series with the capacitance / inductance test circuit 22; one side and the other side of the capacitance / inductance test hole 21 are both connected to the capacitance / inductance test circuit 22, so that the capacitance / inductance test hole 21, the capacitance / inductance switch 23, and the capacitance / inductance test circuit 22 are in series.

[0042] In other embodiments, as Figure 3 shown, one end of the capacitance / inductance test switch 23 is connected to the capacitance / inductance test circuit 22, the other end of the capacitance / inductance test switch 23 is connected to one side of the capacitance / inductance test hole 21, and the other side of the capacitance / inductance test hole 21 is connected to the capacitance / inductance test circuit 22, so that the capacitance / inductance test switch 23, the capacitance / inductance test hole 21, and the capacitance / inductance test circuit 22 are in series.

[0043] The capacitance / inductance test switch 23 is connected to the capacitance / inductance test circuit 22 to control whether the capacitance / inductance test circuit 22 is turned on and operates.

[0044] The capacitance / inductance test hole 21 is provided on the multimeter body 1 of the multimeter. The capacitance / inductance to be measured is directly inserted into the capacitance / inductance test hole 21 through the capacitance / inductance test hole 21 on the multimeter body 1. Since the capacitance / inductance test hole 21 is directly connected to the capacitance / inductance test circuit 22, the path between the capacitance / inductance and the capacitance / inductance test circuit 22 is reduced, the test error is significantly reduced, and the influence of the traditional multimeter on the test result through the long test lead wire is effectively avoided, improving the measurement accuracy. Among them, the capacitance / inductance test circuit 22 can automatically identify the capacitance or inductance. When measuring the capacitance / inductance to be measured, only the capacitance / inductance to be measured needs to be directly inserted into the capacitance / inductance test hole 21, that is, the capacitance / inductance to be measured is connected to the capacitance / inductance test circuit 22, and the capacitance / inductance test circuit 22 will automatically identify it as a capacitance or inductance and complete the corresponding measurement.

[0045] In this embodiment, as Figure 4 shown, the capacitance / inductance test circuit 22 includes: a first pin A0, a second pin A1, an analog ground pin AGND, a first measurement unit, and a second measurement unit. The first pin is respectively connected to the first end of the first measurement unit and the first end of the second measurement unit. The second pin is respectively connected to the second end of the first measurement unit and the second end of the second measurement unit. The analog ground pin is connected to the third end of the first measurement unit;

[0046] The first pin A0 is connected to one end of a first reference resistor Rref1. The second pin A1 is connected to one end of a second reference resistor Rref2. The analog ground pin AGND is connected to one end of an external capacitance / inductance to be measured through one of the test holes of the capacitance / inductance test hole 21. The other end of the capacitance / inductance to be measured is respectively connected to the other end of the first reference resistor Rref1 and the other end of the second reference resistor Rref2 through the other test hole of the capacitance / inductance test hole 21.

[0047] In this embodiment, both the second test unit and the first test unit are integrated into a measurement chip 100.

[0048] In this embodiment, the second measurement unit includes a current source I, a first switch SW1, a second switch SW2, a third switch SW5, a first comparator 10, a second comparator 20, a first reference voltage VREF1, a second reference voltage VREF2, and a counter 30;

[0049] The current source I is respectively connected to the working voltage VDD and the ground terminal GND. The current source I is connected to the first end of the second measurement unit through the first switch SW1, and the current source I is connected to the first end of the second measurement unit through the second switch SW2; the second end of the second measurement unit is respectively connected to the first input terminal of the first comparator and the first input terminal of the second comparator through the third switch SW5. The second input terminal of the first comparator is connected to the first reference voltage VREF1, and the second input terminal of the second comparator is connected to the second reference voltage VREF2. The output terminals of the first comparator and the second comparator are respectively connected to the counter;

[0050] The first measurement unit includes a first operational amplifier OP1, a second operational amplifier OP2, a fourth switch SW3, a fifth switch SW4, a sixth switch SW6, a seventh switch SW7, a sine signal source VSIN, and an ADC module;

[0051] The first end of the first measurement unit is connected to the output terminal of the second operational amplifier through the fourth switch SW3, and the first end of the first measurement unit is connected to the first pin of the ADC module; the second end of the first measurement unit is connected to the second pin of the ADC module, and the second end of the first measurement unit is connected to the inverting input terminal of the second operational amplifier unit through the fifth switch SW4. The third end of the first measurement unit is respectively connected to the third pin of the ADC module, the inverting input terminal of the first operational amplifier, and the output terminal of the first operational amplifier. The non-inverting input terminal of the first operational amplifier is connected to the ground terminal through the sixth switch SW6, and the non-inverting input terminal of the first operational amplifier is sequentially connected to the ground terminal through the seventh switch SW7 and the sine signal source VSIN.

[0052] In other embodiments, the capacitance / inductance test circuit may also adopt other detection circuits.

[0053] In other embodiments, the multimeter further includes: a triode test hole 6 and a triode test circuit 3; the capacitance / inductance test holes are integrated in some of the test holes of the triode test hole 6.

[0054] Integrating the capacitance / inductance test holes in some of the test holes of the triode test hole 6, designing a switching circuit for the capacitance / inductance test circuit 23 and the triode test circuit 3 to realize the test of the triode or the test of the capacitance / inductance. This way of not needing to reset the capacitance / inductance test holes on the multimeter body 1 and only by reusing the existing triode test hole 6 can realize the accurate measurement of the capacitance / inductance, and at the same time reduce the manufacturing cost of the multimeter and is easier to promote.

[0055] In other embodiments, such as Figures 4 to 5 As shown, the multimeter further includes: a switching circuit for switching between the capacitance / inductance test circuit 22 and the triode test circuit 3, and the switching circuit includes first to fourth switching switches; a first end of the triode test circuit 3 is connected to one end of the first switching switch 71, the other end of the first switching switch 71 is connected to the second switching switch 72, the other end of the second switching switch 72 is connected to the first end of the capacitance / inductance test circuit 22, a second end of the triode test circuit 3 is connected to one end of the third switching switch 73, the other end of the third switching switch 73 is connected to one end of the fourth switching switch 74, the other end of the fourth switching switch 74 is connected to the second end of the capacitance / inductance test circuit 22, the triode test hole 6 is arranged between the other end of the first switching switch 71 and one end of the second switching switch 72, and the capacitance / inductance test hole 21 is arranged between the other end of the third switching switch 73 and one end of the fourth switching switch 74.

[0056] Moreover, through the designed switching circuit between the capacitance / inductance test circuit 22 and the triode test circuit 3, when the multimeter is in use, it only needs to select different gears through the function switching switch knob on the multimeter dial, and then different test holes can be conveniently connected to the corresponding test circuits. That is, when measuring inductance / capacitance, it can be switched to the capacitance / inductance test circuit 22, and when measuring a triode, it can be switched to the triode test circuit 3. The operation of the user is very simple, and the user experience is also improved.

[0057] In this embodiment, the multimeter further includes: a display screen, and the display screen is arranged on the surface of the multimeter body 1 for displaying the values of capacitance / inductance.

[0058] In this embodiment, the multimeter further includes: an indicator light, and the indicator light is arranged on the surface of the multimeter body 1 for indicating the on / off status of the capacitance / inductance test circuit.

[0059] In this embodiment, the multimeter further includes: a sound generator; the sound generator is arranged on the surface of the multimeter body 1 for voice reporting and prompting, and for judging the insertion of capacitance / inductance through sound.

[0060] In the embodiments provided by the present application, the working principle of the multimeter is as follows:

[0061] The capacitance / inductance test hole 21 is directly provided on the existing multimeter body 1. During use, only need to switch the capacitance / inductance test switch 23 to the capacitance / inductance mode, and directly insert the capacitance / inductance to be measured into the capacitance / inductance test hole 21. Since the capacitance / inductance test hole 21 is directly connected to the capacitance / inductance test circuit 22, the path between the capacitance / inductance and the capacitance / inductance test circuit 22 is reduced, the test error is significantly reduced, the influence of the traditional multimeter on the test result through the long test lead is effectively avoided, and the measurement accuracy is improved.

[0062] In another embodiment provided by the present application, the working principle of the multimeter is as follows:

[0063] Integrate the capacitance / inductance test hole into some test holes of the triode test hole 6, and design a switching circuit for the capacitance / inductance test circuit 22 and the triode test circuit 3. During use, only need to select different gears of the function switching switch knob on the multimeter dial to realize the switching between the capacitance / inductance test circuit 22 and the triode test circuit 3, conveniently connect different test holes to the corresponding test circuits, and directly insert the capacitance / inductance or triode to be measured into the triode test hole 6 to realize the test of the triode or the test of the capacitance / inductance. In this way, without re-setting the capacitance / inductance test hole on the multimeter body 1, only by reusing some test holes of the existing triode test hole 6, the accurate measurement of the capacitance / inductance is realized, and at the same time, the manufacturing cost of the multimeter is reduced, which is easier to promote.

[0064] Finally, it is stated that any modification or equivalent replacement of some or all technical features carried out relying on the device structure of the present application and the technical solutions of the embodiments, whose essence does not deviate from the corresponding technical solutions of the present application, all belong to the patent scope of the device structure of the present application and the embodiments.

Claims

1. A multimeter, characterized in that: include: A multimeter body, a capacitance / inductance test unit, a transistor test hole, a transistor test circuit, and a switching circuit between the capacitance / inductance test circuit and the transistor test circuit; The capacitance / inductance test unit comprises: a capacitance / inductance test hole, a capacitance / inductance test switch, and a capacitance / inductance test circuit; The capacitance / inductance test hole is arranged on the surface of the multimeter body and is integrated with a part of the transistor test hole, and the capacitance / inductance is connected to the capacitance / inductance test circuit through the capacitance / inductance test hole; The capacitance / inductance test switching switch is arranged on the surface of the multimeter body, and is used to control whether the capacitance / inductance test circuit is working; The capacitance / inductance test circuit is arranged inside the multimeter body; The capacitance / inductance test hole and the capacitance / inductance test switch are both connected to the capacitance / inductance test circuit; The switching circuit of the capacitance / inductance test circuit and the transistor test circuit is connected to the capacitance / inductance test circuit and the transistor test circuit for switching between the transistor test circuit and the capacitance / inductance test circuit.

2. A multimeter as claimed in claim 1, characterized in that: The multimeter body has a function switching switch knob, and the capacitance / inductance test switching switch is integrated in the function switching switch knob of the multimeter body.

3. A multimeter as claimed in claim 1, characterized in that: One end and the other end of the capacitance / inductance test switching switch are connected to the capacitance / inductance test circuit, so that the capacitance / inductance test switching switch is connected in series with the capacitance / inductance test circuit; one side and the other side of the capacitance / inductance test hole are connected to the capacitance / inductance test circuit, so that the capacitance / inductance test hole, the capacitance / inductance test switching switch, and the capacitance / inductance test circuit are connected in series.

4. A multimeter as claimed in claim 1, characterized in that: One end of the capacitance / inductance test switching switch is connected to the capacitance / inductance test circuit, the other end of the capacitance / inductance test switching switch is connected to one side of the capacitance / inductance test hole, and the other side of the capacitance / inductance test hole is connected to the capacitance / inductance test circuit, so that the capacitance / inductance test switching switch, the capacitance / inductance test hole, and the capacitance / inductance test circuit are connected in series.

5. A multimeter as claimed in claim 1, characterized in that: Also includes: The switching circuit includes first to fourth switching switches; the first end of the transistor test circuit is connected to one end of the first switching switch, the other end of the first switching switch is connected to the second switching switch, the other end of the second switching switch is connected to the first end of the capacitor / inductor test circuit, the second end of the transistor test circuit is connected to one end of the third switching switch, the other end of the third switching switch is connected to one end of the fourth switching switch, the other end of the fourth switching switch is connected to the second end of the capacitor / inductor test circuit, the transistor test hole is arranged between the other end of the first switching switch and one end of the second switching switch, and the capacitor / inductor test hole is arranged between the other end of the third switching switch and one end of the fourth switching switch.

6. A multimeter as claimed in claim 1, characterized in that: Also includes: A display screen is arranged on the surface of the multimeter body and is used to display the value of capacitance / inductance.

7. A multimeter as claimed in claim 1, characterized in that: Also includes: An indicator light is arranged on the surface of the multimeter body, and is used to display the on / off status of the capacitance / inductance test circuit.

8. A multimeter as claimed in claim 1, characterized in that: Also includes: Sounder; The sound generator is arranged on the surface of the multimeter body and is used for sound reading and prompting.

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