Multimeter protection device and multimeter

Abstract

The utility model provides a multimeter protection device and a multimeter. The device includes: a key module, a delay module, a switch module and a relay; the trigger input end of the delay module is connected to the output end of the key module, and the output end is connected to the control end of the switch module; the first end of the switch module is connected to the DC power supply end, and the second end is used to power the coil of the relay; the two contacts of the relay are respectively connected to the first terminal and the second terminal; when the key of the key module is pressed, the key module sends a trigger signal to the delay module; when the delay module receives the trigger signal, it sends a conduction signal to the switch module, the test pen path is connected, and the multimeter can be used normally; the delay module sends a disconnection signal after a preset time, the test pen path is disconnected, and the test cannot be performed. The key needs to be pressed again for the next test. This application needs to press the key before each use to be used normally, reminding the user to check whether the multimeter gear and the test pen position are correct to avoid burning the multimeter.

Description

Technical Field

[0001] The utility model relates to the technical field of multimeters, in particular to a multimeter protection device and a multimeter. Background Art

[0002] Multimeters can be used to measure physical quantities such as voltage, current, and resistance, and are widely used in circuit repair, electronic circuit experiments, automobile repair, home appliance repair, and many other scenarios.

[0003] refer to Figure 1 The multimeter has two test leads, one black test lead (negative pole) and one red test lead (positive pole); four measuring test lead holes, three red and one black, the black one is the common end and the red one is the functional end; a gear conversion switch, which is used to switch the gear to cooperate with the measuring test lead for measurement. In order to achieve the measurement of different physical quantities, it is necessary to frequently switch the gear conversion switch and the measuring test lead hole.

[0004] In the prior art, the above switching needs to be performed manually by workers. Since the multimeter lacks an effective prompt function, when the worker is not concentrating, the gear switch and the measuring probe hole are not switched, or the switching does not correspond to the measured physical quantity, the multimeter will be burned out. Utility Model Content

[0005] The embodiment of the utility model provides a multimeter protection device and a multimeter, so as to solve the problem that the multimeter lacks an effective prompting device, causing the multimeter to be frequently burned out.

[0006] In a first aspect, an embodiment of the utility model provides a multimeter protection device, which is connected in series to a red test lead of a multimeter or in series to a black test lead of a multimeter through a first wiring terminal and a second wiring terminal; the multimeter protection device includes: a button module, a delay module, a switch module and a relay;

[0007] The trigger input end of the delay module is connected to the output end of the key module, and the output end of the delay module is connected to the control end of the switch module;

[0008] The first end of the switch module is connected to the DC power supply end, and the second end of the switch module supplies power to the coil of the relay; the two contacts of the relay are respectively connected to the first wiring terminal and the second wiring terminal; wherein the DC power supply end is used to connect to the DC power supply;

[0009] The key module includes a key; when the key is pressed, the key module sends a trigger signal to the delay module;

[0010] The delay module is used to send a conduction signal to the switch module when receiving a trigger signal, and send a disconnection signal to the switch module after a preset delay time;

[0011] The switch module is turned on when receiving a conduction signal, the coil of the relay is energized and the two contacts of the relay are connected; the switch module is disconnected when receiving a disconnection signal, the coil of the relay is de-energized, and the two contacts of the relay are disconnected.

[0012] Optionally, the delay module includes: a delay chip, a first resistor and a second resistor;

[0013] A delay chip, wherein the oscillation input end and the oscillation output end are respectively connected to the first end of the first resistor and the second end of the first resistor, the trigger end is respectively connected to the first end of the second resistor and the trigger input end of the delay module, and the output end is connected to the output end of the delay module;

[0014] The second end of the second resistor is connected to the DC power supply end.

[0015] Optionally, the first resistor is an adjustable resistor.

[0016] Optionally, the button is a touch switch; the delay chip is triggered by a falling edge or a rising edge; the first end of the button is grounded, and the second end of the button is connected to the output end of the button module;

[0017] When the key is pressed, the second end of the key is connected to the first end of the key;

[0018] When the key is released, the second end of the key is disconnected from the first end of the key.

[0019] Optionally, the switch module includes: a switch tube;

[0020] The first end of the switch tube is connected to the first end of the switch module, the second end of the switch tube is connected to the second end of the switch module, and the control end of the switch tube is connected to the control end of the switch module.

[0021] Optionally, the switch tube is a triode;

[0022] The collector of the triode is connected to the first end of the switch tube, the emitter of the triode is connected to the second end of the switch tube, and the base of the triode is connected to the control end of the switch tube.

[0023] Optional, the preset duration is 12S.

[0024] Optionally, the above device further includes: a DCDC module;

[0025] The input end of the DCDC module is used to be connected to a DC power supply, and the output end of the DCDC module is connected to a DC power supply end.

[0026] Optionally, the DC power supply is an internal power supply of the multimeter.

[0027] In a second aspect, an embodiment of the utility model provides a multimeter, comprising: a multimeter body and the multimeter protection device provided in the first aspect of the embodiment of the utility model;

[0028] The multimeter protection device is connected in series in the black test lead of the multimeter through the first connection terminal and the second connection terminal, or is connected in series in the red test lead of the multimeter.

[0029] The utility model embodiment provides a multimeter protection device and a multimeter. The multimeter protection device is connected in series in the red test lead of the multimeter or in series in the black test lead of the multimeter through a first wiring terminal and a second wiring terminal; the multimeter protection device includes: a key module, a delay module, a switch module and a relay; the trigger input end of the delay module is connected to the output end of the key module, and the output end of the delay module is connected to the control end of the switch module; the first end of the switch module is connected to the DC power supply end, and the second end of the switch module supplies power to the coil of the relay; the two contacts of the relay are respectively connected to the first wiring terminal and the second wiring terminal; wherein the DC power supply end is used to connect to the DC power supply; the key module includes a key; when the key is pressed, the key module sends a trigger signal to the delay module; the delay module is used to send a conduction signal to the switch module when receiving the trigger signal, and send a disconnection signal to the switch module after a preset delay time; the switch module is turned on when receiving the conduction signal, the coil of the relay is energized and actuated, and the two contacts of the relay are connected; the switch module is disconnected when receiving the disconnection signal, the coil of the relay loses power, and the two contacts of the relay are disconnected. The multimeter protection device is connected in series in the red test pen or the black test pen to control the on and off of the multimeter measurement path. When the button in the button module is pressed, the button module sends a trigger signal to the delay module; after receiving the trigger signal, the delay module sends a conduction signal to the switch module to control the switch module to conduct, the relay is energized, and the two contacts of the relay are connected, so that the measurement path of the multimeter is connected, and the multimeter can be used normally; after the delay is preset for a long time, the delay module outputs a disconnection signal, controls the switch module to disconnect, the relay loses power, and the two contacts of the relay are disconnected, so that the measurement path of the multimeter is disconnected, and the multimeter cannot be used normally. Among them, the preset time length can ensure that the multimeter completes the measurement at one time. Therefore, before using the multimeter each time, it is necessary to press the button. By adding the operation of button activation, the user is prompted to check the gear position and the measuring pen hole, so as to avoid burning the multimeter due to gear error or wrong connection of the measuring pen hole, and effectively reduce the probability of damage to the multimeter. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1 It is the appearance diagram of the multimeter in the prior art;

[0032] Figure 2 This is a schematic diagram of the circuit structure of a multimeter protection device provided by an embodiment of the utility model;

[0033] Figure 3 It is a circuit principle diagram of a multimeter protection device provided by an embodiment of the utility model;

[0034] Figure 4 The figure is an appearance diagram of a multimeter provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0035] In order to enable people in the technical field to better understand the present solution, the technical solution in the embodiment of the present solution will be clearly described below in conjunction with the drawings in the embodiment of the present solution. Obviously, the described embodiment is an embodiment of a part of the present solution, not all of the embodiments. Based on the embodiments in the present solution, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present solution.

[0036] The term "including" and any other variations in the specification and claims of this solution and the above drawings mean "including but not limited to", and is intended to cover non-exclusive inclusions and is not limited to the examples listed in the text. In addition, the terms "first" and "second" are used to distinguish different objects, not to describe a specific order.

[0037] Figure 1 The figure shows the appearance of a multimeter. Figure 1 The multimeter is equipped with a gear switch, which is used to switch gears to cooperate with the measuring probe for measurement. For example, the commonly used gears are: voltage, resistance, on / off, and current. When the gear switch is in different gears, the corresponding probe should also be in the corresponding probe hole to achieve the measurement of different physical quantities.

[0038] For example, if the staff uses it improperly and does not switch the gear switch and the test lead hole after measuring weak current, and directly measures strong current, it will cause the fuse to burn out.

[0039] In response to the above problems, Figure 2This is a schematic diagram of the structure of a multimeter protection device provided by an embodiment of the utility model. Figure 2 The multimeter protection device is connected in series to the red test lead of the multimeter or in series to the black test lead of the multimeter through the first terminal OUT1 and the second terminal OUT2;

[0040] The multimeter protection device includes: a button module 11, a delay module 12, a switch module 13 and a relay K1;

[0041] The trigger input end of the delay module 12 is connected to the output end of the key module 11, and the output end of the delay module 12 is connected to the control end of the switch module 13;

[0042] The first end of the switch module 13 is connected to the DC power supply terminal VCC, and the second end of the switch module 13 is used to supply power to the coil of the relay K1; the two contacts of the relay K1 are respectively connected to the first wiring terminal OUT1 and the second wiring terminal OUT2; wherein the DC power supply terminal VCC is used to connect to the DC power supply;

[0043] The button module 11 includes a button; when the button is pressed, the button module 11 sends a trigger signal to the delay module 12;

[0044] The delay module 12 is used to send a conduction signal to the switch module 13 upon receiving a trigger signal, and send a disconnection signal to the switch module 13 after a preset delay time;

[0045] The switch module 13 is turned on when receiving a turn-on signal, the coil of the relay K1 is energized and the two contacts of the relay K1 are turned on; the switch module 13 is turned off when receiving a turn-off signal, the coil of the relay K1 is de-energized, and the two contacts of the relay K1 are turned off.

[0046] In the embodiment of the utility model, the multimeter protection device is connected in series in the red test lead or the black test lead to control the on and off of the multimeter measurement path. When the button in the button module 11 is pressed, the button module 11 sends a trigger signal to the delay module 12; after receiving the trigger signal, the delay module 12 sends a conduction signal to the switch module 13 to control the switch module 13 to be turned on, the relay K1 is energized, and the two contacts of the relay K1 are connected, so that the measurement path of the multimeter is connected, and the multimeter can be used normally; after the delay is preset for a long time, the delay module 12 outputs a disconnection signal, controls the switch module 13 to be disconnected, the relay K1 loses power, and the two contacts of the relay K1 are disconnected, so that the measurement path of the multimeter is disconnected, and the multimeter cannot be used normally. Therefore, before using the multimeter each time, it is necessary to press the button for the multimeter to be used normally. By setting the button to prompt the user to check whether the gear switch and the test lead hole are set correctly, the safety of the use of the multimeter is improved to a certain extent, and the risk of the multimeter being burned is reduced. At the same time, each time the button is pressed, the measurement path of the multimeter is automatically disconnected after a preset time, ensuring that the button still needs to be pressed the next time the multimeter is used.

[0047] It should be noted that the preset time should not be too short to ensure that one measurement can be completed; at the same time, the preset time should not be too long to ensure that the multimeter measurement path is disconnected before the next measurement.

[0048] Specifically, the preset duration can be set according to actual application requirements.

[0049] In a possible implementation, the preset duration may be 12 seconds.

[0050] 12S can ensure that one measurement is completed.

[0051] In one possible implementation, reference Figure 3 , the delay module 12 may include: a delay chip U1, a first resistor R1 and a second resistor R2;

[0052] The delay chip U1, the oscillation input end and the oscillation output end are respectively connected to the first end of the first resistor R1 and the second end of the first resistor R1, the trigger end is respectively connected to the first end of the second resistor R2 and the trigger input end of the delay module 12, and the output end is connected to the output end of the delay module 12;

[0053] The second end of the second resistor R2 is connected to the DC power supply end VCC.

[0054] In the implementation of the utility model, a delay chip U1 is used for delay, and the first resistor R1 is used to configure the delay time, that is, the preset time. The second resistor R2 is a pull-up resistor. The delay chip U1 can be triggered by a falling edge. Exemplarily, when the button S1 is not pressed, the trigger end is set to a high level through the second resistor R2; when the button S1 is pressed, the trigger end is a low level, the trigger end of the delay chip U1 is triggered by a falling edge, and the output end outputs a conduction signal, and the timing is started at the same time; when the preset time is reached, the output end of the delay chip U1 outputs a disconnection signal.

[0055] Specifically, the on signal may be a high level, and the off signal may be a low level.

[0056] In a possible implementation, the first resistor R1 may be an adjustable resistor.

[0057] The first resistor R1 is used to configure the delay time, and therefore, the resistor may be an adjustable resistor for adjusting the preset time.

[0058] In one possible implementation, reference Figure 3 , the button S1 can be a touch switch; the delay chip U1 is triggered by the falling edge or the rising edge; the first end of the button S1 is grounded, and the second end of the button S1 is connected to the output end of the button module 11;

[0059] When the button S1 is pressed, the second end of the button S1 is connected to the first end of the button S1;

[0060] When the button S1 is released, the second end of the button S1 is disconnected from the first end of the button S1.

[0061] In the embodiment of the utility model, the button S1 is a touch switch; when the button S1 is pressed, the button module 11 outputs a low level; when the button S1 is released, the button module 11 outputs a high level; thus, the button module 11 outputs a rising edge and a falling edge, and the delay chip U1 is triggered.

[0062] In one possible implementation, reference Figure 3 , the switch module 13 may include: a switch tube Q1;

[0063] A first end of the switch tube Q1 is connected to a first end of the switch module 13 , a second end of the switch tube Q1 is connected to a second end of the switch module 13 , and a control end of the switch tube Q1 is connected to a control end of the switch module 13 .

[0064] The embodiment of the utility model adopts a switch tube Q1 to realize the structure, which is simple and low in cost.

[0065] In a possible implementation, the switch tube Q1 may be a triode;

[0066] The collector of the transistor is connected to the first end of the switch tube Q1 , the emitter of the transistor is connected to the second end of the switch tube Q1 , and the base of the transistor is connected to the control end of the switch tube Q1 .

[0067] Exemplary, reference Figure 3 The transistor is an NPN transistor. When the button S1 is pressed, the delay module 12 outputs a high level, the transistor is turned on, the relay K1 is powered, and the multimeter measurement path is turned on; when the preset time is reached, the delay module 12 outputs a low level, the transistor is turned off, the relay K1 is powered off, and the multimeter measurement path is disconnected. Thus, the control of the multimeter measurement path is realized through the transistor.

[0068] In a possible implementation manner, the above device may further include: a DCDC module;

[0069] The input end of the DCDC module is used to be connected to a DC power supply, and the output end of the DCDC module is connected to a DC power supply terminal VCC.

[0070] In the embodiment of the utility model, a DCDC module may also be provided for voltage conversion, so that the voltage of the DC power supply can power the multimeter protection device.

[0071] In a possible implementation manner, the DC power supply is a power supply inside the multimeter.

[0072] In the embodiment of the utility model, the power supply inside the multimeter is used to power the multimeter protection device. For example, the voltage of the power supply inside the multimeter is 8V, and the DCDC module steps down the voltage to convert the voltage of the DC power supply into a voltage of 3V to 5V to power the multimeter protection device, thereby meeting the power supply requirements.

[0073] In a second aspect, an embodiment of the utility model provides a multimeter, comprising: a multimeter body and the multimeter protection device provided in the first aspect of the embodiment of the utility model;

[0074] The multimeter protection device is connected in series to the black test lead of the multimeter through the first terminal OUT1 and the second terminal OUT2, or is connected in series to the red test lead of the multimeter.

[0075] In the embodiment of the utility model, the multimeter protection device can be integrated inside the multimeter. Figure 4 , a hole can be opened in the multimeter housing, and the button S1 can be embedded in the housing. The user presses the button S1 to activate the multimeter and start measurement, which is convenient for the user.

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multimeter protection device, characterized in that: The multimeter protection device is connected in series to the red test lead of the multimeter or in series to the black test lead of the multimeter through the first wiring terminal and the second wiring terminal; the multimeter protection device includes: a key module, a delay module, a switch module and a relay; The trigger input end of the delay module is connected to the output end of the button module, and the output end of the delay module is connected to the control end of the switch module; The first end of the switch module is connected to the DC power supply end, and the second end of the switch module supplies power to the coil of the relay; the two contacts of the relay are respectively connected to the first wiring terminal and the second wiring terminal; wherein the DC power supply end is used to connect to the DC power supply; The key module includes a key; when the key is pressed, the key module sends a trigger signal to the delay module; The delay module is used to send a conduction signal to the switch module when receiving the trigger signal, and send a disconnection signal to the switch module after a preset delay time; The switch module is turned on when receiving the on signal, the coil of the relay is energized and the two contacts of the relay are connected; the switch module is turned off when receiving the off signal, the coil of the relay is de-energized and the two contacts of the relay are disconnected.

2. The multimeter protection device according to claim 1, characterized in that: The delay module includes: a delay chip, a first resistor and a second resistor; The delay chip, the oscillation input end and the oscillation output end are respectively connected to the first end of the first resistor and the second end of the first resistor, the trigger end is respectively connected to the first end of the second resistor and the trigger input end of the delay module, and the output end is connected to the output end of the delay module; The second end of the second resistor is connected to the DC power supply end.

3. The multimeter protection device as claimed in claim 2, characterized in that: The first resistor is an adjustable resistor.

4. The multimeter protection device as claimed in claim 2, characterized in that: The button is a touch switch; the delay chip is triggered by a falling edge or a rising edge; the first end of the button is grounded, and the second end of the button is connected to the output end of the button module; When the button is pressed, the second end of the button is connected to the first end of the button; When the button is released, the second end of the button is disconnected from the first end of the button.

5. The multimeter protection device according to any one of claims 1 to 4, characterized in that: The switch module comprises: a switch tube; The first end of the switch tube is connected to the first end of the switch module, the second end of the switch tube is connected to the second end of the switch module, and the control end of the switch tube is connected to the control end of the switch module.

6. The multimeter protection device according to claim 5, characterized in that: The switch tube is a triode; The collector of the triode is connected to the first end of the switch tube, the emitter of the triode is connected to the second end of the switch tube, and the base of the triode is connected to the control end of the switch tube.

7. The multimeter protection device according to any one of claims 1 to 4, characterized in that: The preset duration is 12S.

8. The multimeter protection device according to any one of claims 1 to 4, characterized in that: Also includes: DCDC module; The input end of the DCDC module is used to be connected to the DC power supply, and the output end of the DCDC module is connected to the DC power supply end.

9. The multimeter protection device according to claim 8, characterized in that: The DC power supply is the power supply inside the multimeter.

10. A multimeter, characterized in that: include: A multimeter body and a multimeter protection device as claimed in any one of claims 1 to 9; The multimeter protection device is connected in series to the black test lead of the multimeter through the first wiring terminal and the second wiring terminal, or is connected in series to the red test lead of the multimeter.

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