Digital multimeter with anti-error function

Abstract

The invention discloses a digital multimeter with an anti-misoperation function, which comprises a shell, and is characterized in that the interior of the shell is of a hollow structure, an anti-skid patch is fixedly connected to one side of the shell, a threaded column is fixedly connected to the bottom of the inner wall of the shell, a circuit module is fixedly connected to the top of the threaded column, and the anti-skid patch is fixedly connected to the bottom of the inner wall of the shell. The top of the circuit module is fixedly connected with a first needle seat and a second needle seat, one side of the inner wall of the shell is fixedly connected with a heater, the top of the circuit module is fixedly connected with an electromagnetic circuit breaker, the electromagnetic circuit breaker comprises a rear contact plate, the bottom of the rear contact plate is fixedly connected with the first needle seat, and the bottom of the rear contact plate is fixedly connected with the second needle seat. According to the universal meter, the possibility that the universal meter slips in a low-temperature and humid environment is reduced, the situation that the circuit module is touched by mistake due to short circuit or the circuit module is damaged due to the fact that the circuit module is stained with water is reduced, and the reliability and the safety of equipment are improved.

Description

Technical Field

[0001] The invention relates to the technical field of digital multimeters, in particular to a digital multimeter with an anti-error function. Background Art

[0002] Multimeter is an indispensable measuring instrument in power electronics and other departments. It is generally used to measure voltage, current and resistance. It can measure AC and DC current, voltage, resistance and other electrical parameters. The southern region has a cold and damp climate in winter, and many electrical and electronic equipment are susceptible to malfunctions due to the damp and cold environment. During maintenance, maintenance personnel are required to use a multimeter for measurement and judgment. However, under the influence of the winter environment, when maintenance personnel use a digital multimeter for testing, unexpected situations may occur due to environmental factors, affecting the maintenance progress and even the safety of equipment and personnel. Summary of the invention

[0003] The object of the present invention is to provide a digital multimeter with an error-proof function to solve the problems raised in the above background technology.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a digital multimeter with an anti-misoperation function, comprising a shell, the interior of the shell is a hollow structure, the shell material is a polymer, a non-slip patch is fixedly connected to one side of the shell, the material of the non-slip patch is a polymer, a threaded column is fixedly connected to the bottom of the inner wall of the shell, the threaded column is a cylindrical ring, and the thread is on its inner surface, a circuit module is fixedly connected to the top of the threaded column, a first needle seat is fixedly connected to the top of the circuit module, a second needle seat is fixedly connected to the top of the circuit module, a heater is fixedly connected to one side of the inner wall of the shell, the heater is made of metal as a whole, an electromagnetic circuit breaker is fixedly connected to the top of the circuit module, the electromagnetic circuit breaker comprises a rear touch plate, the rear touch plate is made of metal, the bottom of the rear touch plate is fixedly connected to the first needle seat, the back of the rear touch plate is fixedly connected to a sliding tube, and a test lead is plugged into the back of the shell, providing an overall solution to prevent the multimeter from being accidentally touched, and reducing the influence of moisture in the air on the circuit module and reducing the probability of the meter body slipping off to reduce the occurrence of accidental touch.

[0005] Preferably, the front of the shell is connected to an air outlet mesh cover, and the back of the shell is connected to an air inlet mesh cover. The material of the air inlet mesh cover is activated carbon, which is used to filter out impurities and moisture in the air entering the shell. A screen is fixedly connected to the top of the shell to display the measured value, the current function of the device and the working status of the device. The bottom of the screen is electrically connected to the top of the circuit module through a cable. A shift knob is rotatably connected to the top of the shell, and the bottom of the shift knob is electrically connected to the top of the circuit module through a wire. The shift knob controls the start and stop status of the device and the measured parameters. The shift knob has four gears: off, DC current, AC current, voltage, and resistance. There are four threaded columns, which are evenly distributed at the four corners of the bottom of the inner wall of the shell, providing an overall solution for the outside of the shell.

[0006] Preferably, there are two anti-slip patches, which are symmetrically distributed about the center plane of the two side surfaces of the shell. One side of the shell is an irregular surface, and the irregular surface of the shell is covered with frosted particles. The top of the shell is connected to an elliptical through hole, and the number of the elliptical through holes is three. The irregular surfaces corresponding to the elliptical through holes of the shell are connected to circular hole groups, and there are three circular hole groups, two of which are sixteen circular holes in each group, and the other group is eight circular holes. The circular hole groups are connected to the elliptical holes, which provides a technical solution for reducing the probability of the watch body slipping off, increases the gripping area through the irregular surface, increases the friction between the watch body and the palm by covering the surface with frosted particles, and dissipates hot air through the through holes to prevent the gripping part from heating up too quickly. At the same time, the hot air entrains moisture on the surface of the gripping part to leave the watch body to prevent the presence of moisture from reducing the friction between the watch body and the palm.

[0007] Preferably, the top of the circuit module is electrically connected to a chipset for monitoring the state of input and output current, calculating the value of current voltage or resistance using the input and output current, and controlling other electronic components. The top of the circuit module is electrically connected to a battery, which is a 9V square stacked battery. The top of the circuit module is fixedly connected to a humistor, which adjusts its resistance value by the humidity in the title, and then adjusts the current passing through the humistor, so that the chipset can judge the humidity state in the shell by the current flowing through the humistor. The bottom of the first needle seat is electrically connected to the top of the circuit module, and the bottom of the second needle seat is electrically connected to the top of the circuit module. The humistor is electrically connected to the circuit module. The screen, the shift knob, the first needle seat, the second needle seat, and the humistor are electrically connected to the chipset through the circuit module, providing a technical solution for the circuit part of a multimeter, and monitoring the humidity state inside the shell by setting a humistor.

[0008] Preferably, the heater comprises a bottom plate, one side of the bottom plate is fixedly connected to one side of the inner wall of the shell, the other side of the bottom plate is fixedly connected to a heating base, the other side of the heating base is fixedly connected to a heating tube, the other side of the bottom plate is fixedly connected to a pipe rack, one side of the pipe rack is connected with a waist hole for fixing the heating tube, one side of the heating tube is plugged with the heating tube through the waist hole, the other side of the heating base is fixedly connected to a heat conducting sheet, the heat conducting sheet is made of a metal structure, one side of the heat conducting sheet is fixedly connected to the other side of the pipe rack, the front side of the heating base is fixedly connected to a wiring head through a wire, and the front side of the heating base is electrically connected to one side of the wiring head through a wire. The bottom of the terminal head is plugged into the second needle seat, and the bottom of the terminal head is electrically connected to the second needle seat. There are two heaters, which are symmetrically distributed about the central plane of the two side surfaces of the shell. The front of the inner wall of the shell is connected to an exhaust fan, and the central axis of the exhaust fan coincides with the central axis of the air outlet mesh cover, which is used to discharge hot air wrapped with water vapor and reduce the air humidity in the shell. The back of the exhaust fan is electrically connected to the top of the circuit module through a wire, providing a technical solution for the dehumidification mechanism, which reduces the humidity in the shell by heating the air in the shell and coordinating the exhaust fan to discharge it, thereby preventing the circuit module from being accidentally touched or the circuit from being damaged due to short circuit due to moisture.

[0009] Preferably, the slide tube is made of polymer, one side of the slide tube is connected with a circular through hole, the front side of the slide tube is connected with a circular through hole, the number of the circular through holes on the front side of the slide tube is two, the back side of the slide tube is fixedly connected with an insert tube, the insert tube includes a front touch plate, the front touch plate is made of metal, the front side of the front touch plate is fixedly connected to the back side of the slide tube, the top of the front touch plate is fixedly connected with a front contact, the front contact is made of metal, the front side of the front contact is a concave arc surface for fitting with the surface of the through hole on one side of the slide tube, the front contact is fixedly connected to the circular through hole on the back side of the slide tube, the rear A rear contact is fixedly connected to the back of the touch plate, the rear contact is made of metal, the surface of the rear contact is fixedly connected to the circular through hole on the front side of the slide tube, the rear contact has the same appearance as the front contact, the rear contact and the front contact are symmetrical about the center plane of the front and back sides of the slide tube, a conductive tube is fixedly connected to the back side of the front touch plate, the back side of the conductive tube is connected to the back side of the shell, a protective tube cap is fixedly connected to the top of the conductive tube, there are two inserts and two rear touch plates, and the central axis positions thereof coincide with the two circular through holes of the slide tube, thereby providing a technical solution for the connection part between the test leads and the meter body of the electromagnetic circuit breaker.

[0010] Preferably, the sliding tube is slidably connected with a plastic sliding rod inside to reduce the wear between the plastic sliding rod and the sliding tube, the surface of the plastic sliding rod is slidably connected with an electromagnet assembly, the electromagnet assembly is fixedly connected with an electromagnetic coil inside, and is used to generate electromagnetic force when power is turned on, the bottom of the electromagnet assembly is fixedly connected to the top of the circuit module, the bottom of the electromagnet assembly is electrically connected to the top of the circuit module, the electromagnet assembly is electrically connected to the chipset through the circuit module, the other side of the sliding tube is fixedly connected to the surface of the sliding tube, the surface of the sliding tube is fixedly connected to a limiting ring, the limiting ring is located on the other side of the sliding tube, the limiting ring of the plastic sliding rod is fixedly connected to one end of the spring, the other end of the spring is fixedly connected to one end of the electromagnet assembly, the spring is used to assist in resetting after the electromagnet assembly ends, the surface of the plastic sliding rod is sleeved with a metal conductive ring, which is used to connect the front touch plate and the rear touch plate, and then connect the test lead and The test body, the number of the metal conductive rings is two, the center planes of the two side surfaces of the metal conductive rings coincide with the center planes of the two circular through holes of the slide tube respectively, the other side of the plastic slide rod is connected with a circular blind hole, the plastic slide rod is fixedly connected with a metal rod core through the blind hole, and is used to induce electromagnetic force to drive the plastic slide rod to slide, the other side of the plastic slide rod is fixedly connected with a limit plate, and is used to limit the movement range of the plastic slide rod, and one side of the inner wall of the shell is fixedly connected with a cross top rod, and is used to limit the movement range of the plastic slide rod, and the central axis of the cross top rod coincides with the central axis of the plastic slide rod, so that the cross top rod and the limit plate cooperate to limit the sliding range of the plastic slide rod, and provide a technical solution for the on-off part of the electromagnetic circuit breaker, and the electromagnet assembly controlled by the chipset drives the plastic slide rod to change its position and thus changes the on-off state of the test pen body, thereby improving the automation and safety of the equipment.

[0011] Preferably, the test lead includes a plug, the front side of the plug is plugged into a conductive tube for connecting the test lead and a test body, the back side of the plug is fixedly connected to the front side of the pen body through a wire, a circular baffle is fixedly connected to the back side of the pen body for blocking the hand and preventing the hand from accidentally touching other parts and causing electric shock when using the test lead for detection, a probe is fixedly connected to the back side of the pen body, and the number of the plug, pen body and probe is two, thereby providing a technical solution for the test lead.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The digital multimeter with error prevention function heats the air in the shell by arranging a heater inside the shell, thereby heating the moisture attached to the surface of the circuit module, and exhausting the air with moisture out of the multimeter with the help of an exhaust fan, thereby preventing the circuit module from being short-circuited or damaged due to water within a certain humidity range, thereby improving the reliability and safety of the device. The digital multimeter with error prevention function increases the friction between the shell and the palm of the user by arranging an anti-skid patch with a through hole on the outside of the shell, thereby preventing the probability of the multimeter slipping off due to moisture on the shell surface in a low-temperature and humid environment, and improving the stability of the grip. At the same time, the anti-skid patch emits a part of hot air through its through hole to prevent the heat generated by the heater from being transferred to the palm of the user too quickly, thereby affecting the use of the user. The digital multimeter with error prevention function is provided with an electromagnetic circuit breaker. When the chipset of the circuit module of the device detects that the corresponding gear exceeds the use range, the electromagnetic circuit breaker is activated to disconnect the connection between the test lead and the meter body, thereby protecting the device from damage by excessive current, thereby protecting the safety of the user and the peripheral equipment, and improving the safety of use. During the resistance measurement process, when it is detected that the measured resistance value is 0 for more than two seconds, the electromagnetic circuit breaker is activated to disconnect the connection between the test lead and the meter body, thereby preventing the multimeter from being damaged due to a short circuit in the resistance range; The digital multimeter with error prevention function cooperates with an electromagnetic circuit breaker, a humidity-sensitive resistor and a circuit module. When the humidity in a shell is too high and exceeds the processing range of a heater and an exhaust fan, the resistance of the humidity-sensitive resistor decreases and the current increases under the influence of the high humidity environment. After receiving a large current signal from the humidity-sensitive resistor, the chipset of the circuit module activates the electromagnetic circuit breaker to disconnect the connection between the test lead and the meter body, thereby preventing the high humidity environment from affecting the measurement result and preventing the circuit module from causing an error of short-circuiting the multimeter, thereby improving the safety of equipment use. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the overall structure of the front side of the present invention; Figure 2 It is a schematic diagram of the overall structure of the back side of the present invention; Figure 3 This is a schematic diagram of the position relationship of the internal mechanism of the housing of the present invention; Figure 4 This is a schematic diagram of the internal structure of the housing of the present invention; Figure 5 This is a schematic diagram of the position relationship of the through holes of the anti-slip patch of the present invention; Figure 6 It is a schematic diagram of the structure of the heater of the present invention; Figure 7 It is a schematic diagram of the internal structure between the front and back of the electromagnetic circuit breaker of the present invention; Figure 8 It is a schematic diagram of the internal structure between the top and the bottom of the electromagnetic circuit breaker of the present invention; Fig. 9 It is a schematic diagram of the overall structure of the electromagnetic circuit breaker of the present invention; Fig.10 The figure is a schematic diagram of the position relationship between the front touch panel, the rear touch panel and the plastic slide bar of the present invention.

[0014] In the figure: 1, housing; 11, anti-slip patch; 12, screen; 13, shift knob; 14, air outlet mesh cover; 15, air inlet mesh cover; 16, threaded column; 2, circuit module; 21, first needle seat; 22, second needle seat; 23, humidity sensitive resistor; 3, heater; 31, bottom plate; 311, heating base; 312, heating tube; 313, heat conducting sheet; 314, terminal head; 315, pipe rack; 32, exhaust fan; 4. Electromagnetic circuit breaker; 41. Insert tube; 411. Conductive tube; 412. Front contact plate; 413. Front contact; 414. Protective tube cap; 42. Sliding tube; 421. Plastic sliding rod; 422. Electromagnet assembly; 423. Limiting plate; 424. Metal conductive ring; 425. Metal rod core; 43. Rear contact plate; 431. Rear contact; 44. Cross push rod; 5. Test lead; 51. Plug; 52. Pen body; 53. Probe. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] See also Figure 1-10The present invention provides a technical solution: a digital multimeter with an anti-error function, comprising a shell 1, which is used to accommodate and protect the internal mechanism and provide a gripping space for a user. The shell 1 is made of a polymer, and the interior of the shell 1 is a hollow structure. An anti-slip patch 11 is fixedly connected to one side of the shell 1, which is used to facilitate the user's grip to reduce the probability of slipping, and prevent the heat generated by the heater 3 from being transferred too quickly to the two sides of the shell 1 to affect the user's use. The number of anti-slip patches 11 is two, and they are symmetrically distributed about the central plane of the two side surfaces of the shell 1. One side of the shell 1 is an irregular surface, and the irregular surface is covered with frosted particles to increase the friction between the user's palm and the irregular surface, thereby reducing the probability of slipping. The top of the shell 1 is connected with an elliptical through hole, and the number of the elliptical through holes is three. The irregular surface corresponding to the elliptical through hole of the shell 1 is connected with a circular hole group, and there are three circular hole groups, two of which are sixteen circular holes in each group, and the other group is eight circular holes. The circular hole group is connected with the elliptical through hole, and the circular through hole group and the elliptical through hole are used to dissipate hot air and its entrained moisture, thereby reducing the anti-slip patch 11. The moisture content on the surface increases the friction between the user's palm and the irregular surface, thereby reducing the probability of the multimeter slipping. The front of the through-hole shell 1 is connected to an air outlet mesh cover 14, which is used to assist in exhausting the hot air inside the shell 1 and prevent external impurities from entering the shell 1 and affecting the multimeter. The back of the shell 1 is connected to an air inlet mesh cover 15, which is made of activated carbon and is used to filter the air entering the shell 1 and intercept impurities and moisture in the air. The top of the shell 1 is fixedly connected with a screen 12 for displaying the test value, test gear and multimeter In working state, the bottom of the screen 12 is electrically connected to the top of the circuit module 2 through a flat cable, and the top of the housing 1 is rotatably connected to a shift knob 13, which is used to adjust different gears to control the start and stop states and measurement parameters of the multimeter. The gears include five gears: off, DC current, AC current, voltage, and resistance. The bottom of the shift knob 13 is electrically connected to the top of the circuit module 2 through a wire. The bottom of the inner wall of the housing 1 is fixedly connected to a threaded column 16. The number of the threaded columns 16 is four, which are evenly distributed at the four corners of the bottom of the inner wall of the housing 1, and are used to fix the circuit module 2; The top of the threaded column 16 is fixedly connected to a circuit module 2 for providing space for installing and connecting electronic components. The top of the circuit module 2 is fixedly connected to a first needle seat 21 for connecting an electromagnetic circuit breaker 4. The top of the circuit module 2 is fixedly connected to a second needle seat 22 for connecting a heater 3. The top of the circuit module 2 is electrically connected to a chipset for performing parameter measurement, multimeter status monitoring, humidity monitoring inside the housing 1, and control and execution of protection measures for the multimeter. The top of the circuit module 2 is electrically connected to a battery for providing power to the multimeter. The battery is a 9V square stacked battery. The battery and the chip The first needle seat 21 is electrically connected to the top of the circuit module 2, a humidifier 23 is fixedly connected to the top of the circuit module 2, and the humidity state inside the housing 1 is detected by using the different resistance values ​​of the humidifier 23 under different humidity. The bottom of the first needle seat 21 is electrically connected to the top of the circuit module 2, the bottom of the second needle seat 22 is electrically connected to the top of the circuit module 2, the humidifier 23 is electrically connected to the circuit module 2, and the screen 12, the shift knob 13, the first needle seat 21, the second needle seat 22, and the humidifier 23 are electrically connected to the chipset through the circuit module 2, so that the chipset receives the signals of the above mechanisms and sends control signals to realize the execution of the multimeter function; A heater 3 is fixedly connected to one side of the inner wall of the shell 1 for heating the air inside the shell 1 and thereby discharging moisture from the surface of the circuit module 2. The heater 3 is made of metal and includes a bottom plate 31 for connecting the heater 3 to the inner wall of the shell 1. One side of the bottom plate 31 is fixedly connected to one side of the inner wall of the shell 1, and the other side of the bottom plate 31 is fixedly connected to a heating base 311. The other side of the heating base 311 is fixedly connected to a heating tube 312, which generates heat when powered on and thereby heats the air. A pipe rack 315 is fixedly connected to the other side of the bottom plate 31 for fixing the heating tube 312. One side of the pipe rack 315 is connected to a waist hole for connecting the heating tube 312. One side of the heating tube 312 is plugged into the heating tube 312 through the waist hole. A heat conducting sheet 313 is fixedly connected to the other side of the heating base 311 for transferring the heat generated by the heating tube 312 to accelerate the temperature rise of the air inside the shell 1. One side of the heat conducting sheet 313 is connected to the pipe rack 315. The other side is fixedly connected, and the front side of the heating base 311 is fixedly connected with a terminal head 314 through a wire, which is used to electrically connect the circuit module 2 and the heater 3. The front side of the heating base 311 is electrically connected to one side of the terminal head 314 through a wire, and the bottom of the terminal head 314 is plugged into the second needle seat 22, and the bottom of the terminal head 314 is electrically connected to the second needle seat 22. There are two heaters 3, which are symmetrically distributed about the central plane of the two side surfaces of the shell 1. The front side of the inner wall of the shell 1 is connected to an exhaust fan 32 for exhausting hot air entrained with moisture. The central axis of the exhaust fan 32 coincides with the central axis of the air outlet mesh cover 14, and the back side of the exhaust fan 32 is electrically connected to the top of the circuit module 2 through a wire. The heater 3 cooperates with the exhaust fan 32 to exhaust the hot air entrained with water vapor from the inside of the shell 1, so as to prevent the circuit module 2 from being short-circuited or damaged due to water within a certain humidity range, thereby improving the reliability and safety of the equipment; The top of the circuit module 2 is fixedly connected with an electromagnetic circuit breaker 4, which is used to control the connection state of the test lead 5 and the multimeter, thereby protecting the multimeter. The electromagnetic circuit breaker 4 includes a rear touch plate 43, which is used to electrically connect the circuit module 2 and the test lead 5. The bottom of the rear touch plate 43 is fixedly connected to the first needle seat 21. The back of the rear touch plate 43 is fixedly connected with a slide tube 42, which is used to limit the displacement direction of the plastic slide rod 421. One side of the slide tube 42 is connected with a circular through hole, and the front of the slide tube 42 is connected with a circular through hole. The front of the slide tube 42 There are two circular through holes. The back of the slide tube 42 is fixedly connected with a plug 41. The plug 41 is made of metal and is used to connect the test lead 5 and the multimeter and transmit current. The plug 41 includes a front touch plate 412, which is used to electrically connect the circuit module 2 and the test lead 5. The front of the front touch plate 412 is fixedly connected to the back of the slide tube 42. The top of the front touch plate 412 is fixedly connected with a front contact 413, which is used to electrically connect the metal conductive ring 424 of the plastic slide rod 421 and the test lead 5. The front of the front contact 413 is a concave arc. The front contact 413 is fixedly connected to the circular through hole on the back of the slide tube 42, and the back of the rear contact plate 43 is fixedly connected to the rear contact 431, which is used to electrically connect the metal conductive ring 424 of the plastic slide rod 421 and the test lead 5. The surface of the rear contact 431 is fixedly connected to the circular through hole on the front of the slide tube 42. The rear contact 431 has the same appearance as the front contact 413. The rear contact 431 and the front contact 413 are symmetrical about the center plane of the front and back of the slide tube 42. The back of the front contact plate 412 is fixedly connected to the conductive ring 424 of the plastic slide rod 421 and the test lead 5. The tube 411 is used to connect the test lead 5 with the multimeter and transmit current. The back of the conductive tube 411 is connected to the back of the housing 1. A protective tube cap 414 is fixedly connected to the top of the conductive tube 411 to protect the back of the conductive tube 411 and reduce the wear caused by the contact between the test lead 5 and the conductive tube 411. The number of the insert tube 41, the front contact plate 412, the front contact 413, the rear contact plate 43, the rear contact 431, and the protective tube cap 414 is two, and the central axis positions thereof coincide with the two circular through holes of the slide tube 42 respectively. A plastic slide bar 421 is slidably connected inside the slide tube 42, which is used to drive the metal conductive ring 424 to slide and cooperate with the metal conductive ring 424 to control the on and off state of the electromagnetic circuit breaker 4; an electromagnet assembly 422 is slidably connected to the surface of the plastic slide bar 421, and an electromagnetic coil is fixedly connected inside the electromagnet assembly 422, which is used to generate electromagnetic force to control the movement state of the plastic slide bar 421 after power is turned on; the bottom of the electromagnet assembly 422 is fixedly connected to the top of the circuit module 2, the bottom of the electromagnet assembly 422 is electrically connected to the top of the circuit module 2, the electromagnet assembly 422 is electrically connected to the chipset through the circuit module 2, the other side of the slide tube 42 is fixedly connected to the surface of the slide tube 42, the surface of the slide tube 42 is fixedly connected to a limiting ring, the limiting ring is located on the other side of the slide tube 42, the limiting ring of the plastic slide bar 421 is fixedly connected to one end of the spring, and the other end of the spring is fixedly connected to one end of the electromagnet assembly 422, which is used for the electromagnet assembly 422 After power failure, the auxiliary plastic slide bar 421 is reset. A metal conductive ring 424 is sleeved on the surface of the plastic slide bar 421, which is used to connect the front contact 413 and the rear contact 431 and then connect the test lead 5 and the multimeter. There are two metal conductive rings 424. The central planes of the surfaces on both sides of the metal conductive ring 424 coincide with the central planes of the two circular through holes of the slide tube 42 respectively. The other side of the plastic slide bar 421 is connected with a circular blind hole. The plastic slide bar 421 is fixedly connected with a metal rod core 425 through the blind hole, which is used to sense the electromagnetic force of the electromagnet assembly 422 and drive the plastic slide bar 421 to move. The other side of the plastic slide bar 421 is fixedly connected with a limit plate 423, which is used to limit the movement range of the plastic slide bar 421. A cross top rod 44 is fixedly connected to one side of the inner wall of the shell 1, which is used to cooperate with the limit plate 423 to limit the movement range of the plastic slide bar 421. The central axis of the cross top rod 44 coincides with the central axis of the plastic slide bar 421. A test lead 5 is plugged into the back of the shell 1 for connecting the multimeter with the device under test or the electronic and electrical components under test. The test lead 5 includes a plug 51. The plug 51 has a cylindrical appearance and is used to connect the test lead 5 with the multimeter. The front of the plug 51 is plugged into the conductive tube 411. The back of the plug 51 is fixedly connected to a pen body 52 through a wire to provide a grip for the user. The pen body 52 is made of insulating plastic to prevent the user from getting an electric shock and improve the safety of the multimeter. A circular baffle is fixedly connected to the back of the pen body 52 to prevent the user from accidentally touching other conductors and getting an electric shock. A probe 53 is fixedly connected to the back of the pen body 52 for connecting the electronic and electrical components under test. The number of the plug 51, the pen body 52, and the probe 53 is two.

[0017] Working principle: The user holds the housing 1 of the multimeter, and the palm of the user contacts and compacts the irregular surface of the anti-slip patch 11. Because the part in contact with the palm is the irregular surface part of the anti-slip patch 11, the irregular surface and the palm have a larger contact area, which increases the force-bearing area and reduces the probability of the multimeter slipping off. Because the irregular surface of the anti-slip patch 11 is covered with frosted particles, the friction coefficient between the palm and the irregular surface is large, which further increases the friction between the palm and the anti-slip patch 11, and further reduces the probability of the multimeter slipping off. When the shift knob 13 is rotated from the closed position to other working positions, the chipset of the circuit module 2 receives the signal of the shift knob 13, connects the battery of the circuit module 2, starts the multimeter, and starts the humidity-sensitive resistor 23 at the same time. The resistance of the humidity-sensitive resistor 23 decreases as the humidity in the housing 1 increases. When the humidity inside the housing 1 causes moisture to adhere to the surface of the circuit module 2, the chipset detects the current value signal transmitted by the humidity-sensitive resistor 23, and determines that the humidity inside the housing 1 is relatively high. The chip set controls the heater 3 to start through the second needle seat 22, and the heater 3 is energized. When the heating tube 312 is powered on, heat is generated. A part of the generated heat is transferred to the air inside the housing 1 through the heat conducting sheet 313. The air inside the housing 1 is heated up, accelerating the volatilization of moisture on the surface of the circuit module 2 with the hot air. At the same time, the exhaust fan 32 is started to discharge the air inside the housing 1 together with the volatilized moisture. While the hot air and moisture are discharged, the outside air enters the housing 1 through the air inlet mesh cover 15 to balance the air pressure inside the housing 1. Impurities and moisture in the outside air are blocked or adsorbed after passing through the air inlet mesh cover 15, thereby reducing the moisture content inside the housing 1. Another part of the heat is transferred to both sides of the housing 1 through the bottom plate 31, and then transferred to the anti-slip patch 11. The overheated air in the through hole is discharged through the through hole. The hot air discharged from the anti-slip patch 11 accelerates the volatilization of moisture on the surface of the anti-slip patch 11, further increasing the friction between the palm and the anti-slip patch 11, and further reducing the probability of the multimeter slipping. When the shift knob 13 is in the working gear, when the parameter value calculated by the chipset of the circuit module 2 is greater than the range of its corresponding gear or the resistance value continuously measured in the resistance gear is 0, the chipset determines that the measurement circuit of the multimeter is in an abnormal condition, and the chipset controls the electromagnet assembly 422 to start, and the electromagnet assembly 422 generates an electromagnetic force to drive the metal rod core 425, and the metal rod core 425 drives the plastic slide bar 421 to move along the slide tube 42, and at the same time squeezes the spring, and the metal conductive ring 424 is separated from the front contact 413 and the rear contact 431, thereby causing the test lead 5 to be disconnected from the multimeter, preventing The abnormal situation is prevented from damaging the circuit module 2. At the same time, the chipset transmits a signal to the screen 12. The screen 12 displays the abnormal situation to remind the user to check in time. After the user eliminates the abnormal situation, the shift knob 13 is turned to the closed gear and then turned to the working gear to restart. The multimeter is powered off, the electromagnet assembly 422 is powered off, and the plastic slide bar 421 slides and resets under the action of the spring. The probe 5 is reconnected to the multimeter. The chipset detects the circuit state. If the measured circuit state is normal, the electromagnet assembly 422 is no longer started. If there is still an abnormality, the electromagnet assembly 422 is started and the above process is repeated to protect the multimeter. When the shift knob 13 is in the working position, after the heater 3 is started, when the current transmitted by the humidistat 23 detected by the chipset continues to exceed the current value corresponding to the normal humidity range, the chipset determines that the humidity in the shell 1 is too high, and the chipset transmits a signal to the screen 12. The screen 12 shows that the internal humidity is too high. After three seconds, the chipset cuts off the electrical connection between the battery and the circuit module 2, and the device is shut down. After the user cleans the moisture inside the shell 1 and reduces the humidity inside the shell 1, the user turns the shift knob 13 to the off position and then to the working position to restart. The chipset continues to detect the current value transmitted by the humidistat 23. If the transmitted current value is within the normal range, the working process is continued to be started. If the current value is higher than the current value within the normal range, the aforementioned process is continued to protect the multimeter to prevent accidental touch and damage to the multimeter due to moisture adhering to the circuit module 2.

[0018] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A digital multimeter with an error-proof function, comprising a housing (1), characterized in that: The shell (1) has a hollow structure inside, an anti-slip patch (11) is fixedly connected to one side of the shell (1), a threaded column (16) is fixedly connected to the bottom of the inner wall of the shell (1), a circuit module (2) is fixedly connected to the top of the threaded column (16), a first needle seat (21) is fixedly connected to the top of the circuit module (2), a second needle seat (22) is fixedly connected to the top of the circuit module (2), a heater (3) is fixedly connected to one side of the inner wall of the shell (1), an electromagnetic circuit breaker (4) is fixedly connected to the top of the circuit module (2), the electromagnetic circuit breaker (4) comprises a rear touch plate (43), the bottom of the rear touch plate (43) is fixedly connected to the first needle seat (21), the back of the rear touch plate (43) is fixedly connected to a slide tube (42), and a test lead (5) is plugged into the back of the shell (1).

2. A digital multimeter with error prevention function according to claim 1, characterized in that: The front of the shell (1) is connected to an air outlet mesh cover (14), the back of the shell (1) is connected to an air inlet mesh cover (15), the top of the shell (1) is fixedly connected to a screen (12), the bottom of the screen (12) is electrically connected to the top of the circuit module (2) via a flat cable, the top of the shell (1) is rotatably connected to a shift knob (13), the bottom of the shift knob (13) is electrically connected to the top of the circuit module (2) via a wire, and the number of the threaded columns (16) is four, which are evenly distributed at the four corners of the bottom of the inner wall of the shell (1).

3. A digital multimeter with error prevention function according to claim 1, characterized in that: The number of the anti-slip patches (11) is two, and they are symmetrically distributed about the central plane of the two side surfaces of the shell (1); one side of the shell (1) is an irregular surface; the top of the shell (1) is connected to an elliptical through hole, the number of the elliptical through holes is three; the irregular surfaces corresponding to the elliptical through holes of the shell (1) are connected to circular hole groups, the number of the circular hole groups is three, two of which have sixteen circular holes each, and the other has eight circular holes, and the circular hole groups are connected to the elliptical holes.

4. A digital multimeter with error prevention function according to claim 2, characterized in that: The top of the circuit module (2) is electrically connected to a chipset, the top of the circuit module (2) is electrically connected to a battery, the battery is a 9V square stacked battery, the top of the circuit module (2) is fixedly connected to a humidity-sensitive resistor (23), the bottom of the first needle seat (21) is electrically connected to the top of the circuit module (2), the bottom of the second needle seat (22) is electrically connected to the top of the circuit module (2), the humidity-sensitive resistor (23) is electrically connected to the circuit module (2), and the screen (12), the shift knob (13), the first needle seat (21), the second needle seat (22), and the humidity-sensitive resistor (23) are electrically connected to the chipset via the circuit module (2).

5. A digital multimeter with error prevention function according to claim 1, characterized in that: The heater (3) comprises a bottom plate (31), one side of the bottom plate (31) is fixedly connected to one side of the inner wall of the shell (1), the other side of the bottom plate (31) is fixedly connected to a heating base (311), the other side of the heating base (311) is fixedly connected to a heating tube (312), the other side of the bottom plate (31) is fixedly connected to a pipe rack (315), one side of the pipe rack (315) is connected to a waist hole, one side of the heating tube (312) is plugged into the heating tube (312) through the waist hole, the other side of the heating base (311) is fixedly connected to a heat conducting plate (313), one side of the heat conducting plate (313) is fixedly connected to the other side of the pipe rack (315), and the heating The front side of the base (311) is fixedly connected to a terminal head (314) via a wire, the front side of the heating base (311) is electrically connected to one side of the terminal head (314) via a wire, the bottom side of the terminal head (314) is plugged into a second needle seat (22), the bottom side of the terminal head (314) is electrically connected to the second needle seat (22), the number of the heaters (3) is two, and they are symmetrically distributed about the central plane of the two side surfaces of the shell (1), the front side of the inner wall of the shell (1) is connected to an exhaust fan (32), the central axis of the exhaust fan (32) coincides with the central axis of the air outlet mesh cover (14), and the back side of the exhaust fan (32) is electrically connected to the top of the circuit module (2) via a wire.

6. A digital multimeter with error prevention function according to claim 1, characterized in that: A circular through hole is connected to one side of the slide tube (42); a circular through hole is connected to the front side of the slide tube (42); the number of the circular through holes on the front side of the slide tube (42) is two; a plug tube (41) is fixedly connected to the back side of the slide tube (42); the plug tube (41) comprises a front touch plate (412); the front side of the front touch plate (412) is fixedly connected to the back side of the slide tube (42); a front contact (413) is fixedly connected to the top of the front touch plate (412); the front side of the front contact (413) is a concave arc surface; the front contact (413) is fixedly connected to the circular through hole on the back side of the slide tube (42); the back side of the rear touch plate (43) is fixedly connected to the rear contact (431); the surface of the rear contact (431) is connected to the slide tube ( The front contact (42) is fixedly connected to the circular through hole on the front side, the rear contact (431) is consistent with the front contact (413) in appearance, the rear contact (431) and the front contact (413) are symmetrical about the center plane of the front and back sides of the slide tube (42), the back side of the front contact plate (412) is fixedly connected to a conductive tube (411), the back side of the conductive tube (411) is connected to the back side of the shell (1), the top of the conductive tube (411) is fixedly connected to a protective tube cap (414), the number of the insert tube (41), the front contact plate (412), the front contact (413), the rear contact plate (43), the rear contact (431), and the protective tube cap (414) is two, and the central axis positions thereof respectively coincide with the two circular through holes of the slide tube (42).

7. A digital multimeter with error prevention function according to claim 6, characterized in that: The sliding tube (42) is slidably connected to a plastic sliding rod (421) inside, and the surface of the plastic sliding rod (421) is slidably connected to an electromagnet assembly (422), and the electromagnet assembly (422) is fixedly connected to an electromagnetic coil inside. The bottom of the electromagnet assembly (422) is fixedly connected to the top of the circuit module (2), and the bottom of the electromagnet assembly (422) is electrically connected to the top of the circuit module (2). The electromagnet assembly (422) is electrically connected to the chipset through the circuit module (2). The other side of the sliding tube (42) is fixedly connected to the surface of the sliding tube (42), and the surface of the sliding tube (42) is fixedly connected to a limiting ring, which is located on the other side of the sliding tube (42). The limiting ring of the plastic sliding rod (421) is fixed to one end of the spring. The plastic slide bar (421) is connected to the outer surface of the slide bar (421), the other end of the spring is fixedly connected to one end of the electromagnet assembly (422), a metal conductive ring (424) is sleeved on the surface of the plastic slide bar (421), the number of the metal conductive rings (424) is two, the center planes of the two side surfaces of the metal conductive rings (424) respectively coincide with the center planes of the two circular through holes of the slide tube (42), the other side of the plastic slide bar (421) is connected to a circular blind hole, the plastic slide bar (421) is fixedly connected to a metal rod core (425) through the blind hole, the other side of the plastic slide bar (421) is fixedly connected to a limit plate (423), and one side of the inner wall of the housing (1) is fixedly connected to a cross top rod (44), the center axis of the cross top rod (44) coincides with the center axis of the plastic slide bar (421).

8. A digital multimeter with error prevention function according to claim 7, characterized in that: The test pen (5) comprises a plug (51), the front face of the plug (51) being plugged into a conductive tube (411), the back face of the plug (51) being fixedly connected to a pen body (52) via a wire, the back face of the pen body (52) being fixedly connected to a circular baffle, the back face of the pen body (52) being fixedly connected to a probe (53), and the number of the plug (51), the pen body (52), and the probe (53) being two.

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