Voltage test circuit adaptive to dry batteries of multiple models

Abstract

The utility model relates to a voltage test circuit adaptive to dry batteries of multiple models. The voltage test circuit comprises a first input circuit, a second input circuit, a control unit MCU and a liquid crystal display. The output end of the first input circuit is connected with the input end of the control unit MCU, the output end of the second input circuit is connected with the input end of the control unit MCU, the output end of the control unit MCU is connected with the input end of the liquid crystal display, and the output end of the first input circuit is connected with the input end of the second input circuit; the first input circuit is used for acquiring the voltage of a 1.5 V dry battery; the second input circuit is used for acquiring the voltage of the 9V dry battery; and the control unit MCU is used for controlling the liquid crystal display to display the voltage measurement result of the 1.5 V or 9V dry battery. And high-precision voltage measurement of 1.5 V and 9V dry batteries is realized. The core value is to solve the compatibility problem of multiple types of batteries, simultaneously consider stability, safety and cost control, and is suitable for various scenes such as household electronic equipment, portable instruments and the like.

Description

TECHNICAL FIELD

[0001] The utility model relates to a voltage test circuit suitable for multiple models of dry batteries belongs to electronic measurement technical field. BACKGROUND

[0002] With the increasing popularity of electronic devices and the wide application of batteries, accurate measurement of battery capacity has become a key problem. As a representative of portable power supply, the state of dry battery capacity directly affects the use time and performance of the device. However, the current market is facing the situation of a variety of dry batteries, including various models, capacity and voltage differences, which undoubtedly brings great challenges to the accurate measurement of battery capacity.

[0003] In order to meet this diverse demand, it is particularly urgent to design a voltage test circuit that can adapt to multiple models of dry batteries. Such a circuit not only needs to have the ability to accurately measure the voltage of different models of dry batteries to accurately judge the state of the battery capacity, but also should perform well in stability, measurement accuracy and operation convenience. Such a circuit will better meet the use requirements in various application scenarios, provide more reliable capacity display for electronic device users, and thus improve the overall use experience. UTILITY MODEL CONTENT

[0004] In order to solve the problems existing in the prior art, the utility model provides a voltage test circuit suitable for multiple models of dry batteries.

[0005] The technical scheme of the utility model is as follows:

[0006] A voltage test circuit suitable for multiple models of dry batteries, comprising a first input circuit, a second input circuit, a control unit MCU and a liquid crystal display;

[0007] The output end of the first input circuit is connected with the input end of the control unit MCU, the output end of the second input circuit is connected with the input end of the control unit MCU, the output end of the control unit MCU is connected with the input end of the liquid crystal display, and the output end of the first input circuit is connected with the input end of the second input circuit;

[0008] The first input circuit is used for acquiring the voltage of 1.5V dry battery;

[0009] The second input circuit is used for acquiring the voltage of 9V dry battery;

[0010] The control unit MCU is used for controlling the liquid crystal display to display the voltage measurement result of 1.5V or 9V dry battery.

[0011] As a preferred embodiment of the utility model, the first input circuit comprises a first triode, a second triode, a first metal contact piece and a second metal contact piece;

[0012] The first metal contact piece is connected with one end of the first resistor, one end of the sixteenth resistor, the emitter of the first transistor and one end of the first inductor respectively, one end of the sixteenth resistor is connected with a 1.5V power supply, the other end of the first resistor is connected with the input end of the control unit MCU and one end of the second resistor respectively, the base of the first transistor is connected with one end of the third resistor and one end of the third capacitor respectively, the other end of the first inductor and the other end of the third capacitor are connected with the positive electrode of the second diode, the negative electrode of the second diode is connected with the input end of the second input circuit;

[0013] The second metal contact piece is connected with the other end of the second resistor, the other end of the sixteenth resistor, the other end of the third resistor and the emitter of the second transistor respectively, the other end of the third resistor is grounded, the base of the second transistor is connected with the collector of the first transistor through the fourth resistor, and the collector of the second transistor is connected with the positive electrode of the second diode;

[0014] The first metal contact piece is used for being connected with the positive electrode of a 1.5V dry battery;

[0015] The second metal contact piece is used for being connected with the negative electrode of the 1.5V dry battery.

[0016] As a preferred embodiment of the utility model, the second input circuit comprises a third metal contact piece, a fourth metal contact piece, a first diode and a voltage stabilizing chip;

[0017] The third metal contact piece is connected with one end of the fifth resistor, one end of the nineteenth resistor and the positive electrode of the first diode, one end of the nineteenth resistor is connected with a 9V power supply, and the other end of the fifth resistor is connected with the input end of the control unit MCU and one end of the sixth resistor respectively;

[0018] The negative electrode of the first diode is connected with one end of an electrolytic capacitor and the input end of the voltage stabilizing chip respectively, the negative electrode of the second diode is connected with one end of the electrolytic capacitor, the output end of the voltage stabilizing chip is connected with one end of the second capacitor and one end of the fourth capacitor respectively, and one end of the fourth capacitor is connected with a 3V power supply;

[0019] The fourth metal contact piece is connected with the other end of the sixth resistor, the other end of the nineteenth resistor, the other end of the electrolytic capacitor, the other end of the second capacitor and the other end of the fourth capacitor respectively, and the grounding end of the voltage stabilizing chip is grounded;

[0020] The third metal contact piece is used for being connected with the positive electrode of a 9V dry battery;

[0021] The fourth metal contact piece is used for being connected with the negative electrode of the 9V dry battery.

[0022] As the preferred embodiment of the utility model, the first metal contact piece, the second metal contact piece, the third metal contact piece and the fourth metal contact piece are strip-shaped.

[0023] As the preferred embodiment of the utility model, the other end of the first resistor is connected with the first data input end of the control unit MCU, and the other end of the fifth resistor is connected with the second data input end of the control unit MCU.

[0024] The power input end of the control unit MCU is connected with a 3V power supply, and the ground end of the control unit MCU is grounded.

[0025] The first control display end of the control unit MCU is connected with the first control display end of the liquid crystal display.

[0026] The second control display end of the control unit MCU is connected with the second control display end of the liquid crystal display.

[0027] The third control display end of the control unit MCU is connected with the third control display end of the liquid crystal display.

[0028] The fourth control display end of the control unit MCU is connected with the fourth control display end of the liquid crystal display.

[0029] The fifth control display end of the control unit MCU is connected with the fifth control display end of the liquid crystal display.

[0030] The sixth control display end of the control unit MCU is connected with the sixth control display end of the liquid crystal display.

[0031] The seventh control display end of the control unit MCU is connected with the seventh control display end of the liquid crystal display.

[0032] The eighth control display end of the control unit MCU is connected with the eighth control display end of the liquid crystal display.

[0033] The ninth control display end of the control unit MCU is connected with the ninth control display end of the liquid crystal display.

[0034] The tenth control display end of the control unit MCU is connected with the tenth control display end of the liquid crystal display.

[0035] The eleventh control display end of the control unit MCU is connected with the eleventh control display end of the liquid crystal display.

[0036] The twelfth control display end of the control unit MCU is connected with the twelfth control display end of the liquid crystal display.

[0037] One end of the seventh resistor is connected with a 3V power supply, and the other end of the seventh resistor is connected with the first control display end of the control unit MCU and grounded through the eighth resistor.

[0038] One end of the ninth resistor is connected with a 3V power supply, and the other end of the ninth resistor is connected with a second control display end of the control unit MCU respectively, and grounded through a tenth resistor;

[0039] One end of the eleventh resistor is connected with a 3V power supply, and the other end of the eleventh resistor is connected with a third control display end of the control unit MCU respectively, and grounded through a twelfth resistor;

[0040] One end of the thirteenth resistor is connected with a 3V power supply, and the other end of the thirteenth resistor is connected with a fourth control display end of the control unit MCU respectively, and grounded through a fourteenth resistor;

[0041] One end of the fifteenth resistor is connected with a 3V power supply, and the other end of the fifteenth resistor is connected with an eighth control display end of the control unit MCU.

[0042] The utility model has the following beneficial effects:

[0043] The utility model discloses a high-precision voltage measurement for 1.5V and 9V dry batteries through the fine design of the first input circuit and the second input circuit, the intelligent processing of the control unit MCU and the dynamic drive of the liquid crystal display, which solves the compatibility problem of multiple models of batteries, and takes into account stability, safety and cost control, and is suitable for various scenes such as household electronic equipment and portable instruments. The 1.5V and 9V input circuits are completely separated, avoiding signal crosstalk caused by voltage range difference. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 It is the module connection drawing of the utility model.

[0045] Figure 2 It is the circuit connection drawing of the first input circuit and the second input circuit of the utility model.

[0046] Figure 3 It is the circuit connection drawing of the control unit MCU and the liquid crystal display of the utility model. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0048] It should be understood that the step numbers used in the text are only for the convenience of description, and are not limited to the execution sequence of the steps.

[0049] It is to be understood that the terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used in this specification and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0050] The terms "comprises", "comprising", "includes", "including", "contains", "containing" or variations thereof do not have a limiting meaning when used in connection with describing the features, integers, steps or components of the present application.

[0051] The term "and / or" means any combination of one or more of the associated listed items and includes all possible combinations.

[0052] Embodiment one:

[0053] In this embodiment, the voltage stabilizing chip is U3 shown in the figure, and the model is 7530. Figure 2

[0054] The first triode is Q1 shown in the figure, and the model is 9012. Figure 2

[0055] The second triode is Q2 shown in the figure, and the model is 9013. Figure 2

[0056] The control unit MCU is U1 shown in the figure, and the model is NY8B062E single-chip microcomputer. Figure 3

[0057] The liquid crystal display is LCD shown in the figure, and satisfies 1 / 4 duty ratio, 1 / 2 bias, and TN positive display liquid crystal. Figure 3

[0058] The first resistor is R1 shown in the figure, the second resistor is R2 shown in the figure, the sixteenth resistor is R16 shown in the figure, the third resistor is R3 shown in the figure, the fourth resistor is R4 shown in the figure, the third capacitor is C3 shown in the figure, the first inductor is L1 shown in the figure, the second diode is D2 shown in the figure, the fifth resistor is R5 shown in the figure, the sixth resistor is R6 shown in the figure, the nineteenth resistor is R19 shown in the figure, the first diode is D1 shown in the figure, and the electrolytic capacitor is shown in the figure. Figure 2 Figure 2 Figure 2 Figure 2 Figure 2 Figure 2 Figure 2 Figure 2 Figure 2 Figure 2 Figure 2 Figure 2 Figure 3 ​​​​​​​​​​​​​​​​​C1, the second capacitor is shown as Figure 3 C2, the fourth capacitor is shown as Figure 3 C4, the fifth capacitor is shown as

[0059] R7, the eighth resistor is shown as Figure 3 R8, the ninth resistor is shown as Figure 3 R9, the tenth resistor is shown as Figure 3 R10, the eleventh resistor is shown as Figure 3 R11, the twelfth resistor is shown as Figure 3 R12, the thirteenth resistor is shown as Figure 3 R13, the fourteenth resistor is shown as Figure 3 R14, the fifteenth resistor is shown as Figure 3 R15, the sixteenth resistor is shown as Figure 3

[0060] U1, the first control display end of the control unit MCU is shown as Figure 3 U1, the second control display end of the control unit MCU is shown as Figure 3 U1, the third control display end of the control unit MCU is shown as Figure 3 U1, the fourth control display end of the control unit MCU is shown as Figure 3 U1, the fifth control display end of the control unit MCU is shown as Figure 3 U1, the sixth control display end of the control unit MCU is shown as Figure 3 U1, the seventh control display end of the control unit MCU is shown as Figure 3 U1, the eighth control display end of the control unit MCU is shown as Figure 3 U1, the ninth control display end of the control unit MCU is shown as Figure 3 U1, the tenth control display end of the control unit MCU is shown as Figure 3 U1, the eleventh control display end of the control unit MCU is shown as Figure 3 U1, the twelfth control display end of the control unit MCU is shown as Figure 3 U1, the power input end of the control unit MCU is shown as Figure 3 U1, the ground end of the control unit MCU is shown as Figure 3 U1, the first data input end of the control unit MCU is shown as Figure 3 U1, the second data input end of the control unit MCU is shown as Figure 1 U1, the third data input end of the control unit MCU is shown as​

[0061] a first control display end of the liquid crystal display is a COM1 port of the LCD shown in the figure, ​ a second control display end of the liquid crystal display is a COM2 port of the LCD shown in the figure, ​ a third control display end of the liquid crystal display is a COM3 port of the LCD shown in the figure, ​ a fourth control display end of the liquid crystal display is a COM4 port of the LCD shown in the figure, ​ a fifth control display end of the liquid crystal display is a SEG1 port of the LCD shown in the figure, ​ a sixth control display end of the liquid crystal display is a SEG2 port of the LCD shown in the figure, ​ a seventh control display end of the liquid crystal display is a SEG3 port of the LCD shown in the figure, ​ an eighth control display end of the liquid crystal display is a SEG4 port of the LCD shown in the figure, ​ a ninth control display end of the liquid crystal display is a SEG5 port of the LCD shown in the figure, ​ a tenth control display end of the liquid crystal display is a SEG6 port of the LCD shown in the figure, ​ an eleventh control display end of the liquid crystal display is a SEG7 port of the LCD shown in the figure, ​ a twelfth control display end of the liquid crystal display is a SEG8 port of the LCD shown in the figure. ​

[0062] Referring to ​ a voltage testing circuit suitable for multiple models of dry batteries, comprising a first input circuit, a second input circuit, a control unit MCU and a liquid crystal display,

[0063] an output end of the first input circuit is connected with an input end of the control unit MCU, an output end of the second input circuit is connected with an input end of the control unit MCU, an output end of the control unit MCU is connected with an input end of the liquid crystal display, and an output end of the first input circuit is connected with an input end of the second input circuit;

[0064] the first input circuit is used for acquiring the voltage of the 1.5V dry battery;

[0065] the second input circuit is used for acquiring the voltage of the 9V dry battery;

[0066] the control unit MCU is used for controlling the liquid crystal display to display the voltage measurement result of the 1.5V or 9V dry battery.

[0067] As a preferred embodiment of the utility model, the first input circuit comprises a first triode, a second triode, a first metal contact sheet and a second metal contact sheet;

[0068] ​The first metal contact piece is connected with one end of the first resistor, one end of the sixteenth resistor, the emitter of the first triode and one end of the first inductor respectively, one end of the sixteenth resistor is connected with a 1.5V power supply, the other end of the first resistor is connected with the input end of the control unit MCU and one end of the second resistor respectively, the base of the first triode is connected with one end of the third resistor and one end of the third capacitor respectively, the other end of the first inductor and the other end of the third capacitor are connected with the positive electrode of the second diode, and the negative electrode of the second diode is connected with the input end of the second input circuit;

[0069] The second metal contact piece is connected with the other end of the second resistor, the other end of the sixteenth resistor, the other end of the third resistor and the emitter of the second triode respectively, the other end of the third resistor is grounded, the base of the second triode is connected with the collector of the first triode through the fourth resistor, and the collector of the second triode is connected with the positive electrode of the second diode;

[0070] The first metal contact piece is used for being connected with the positive electrode of a 1.5V dry battery;

[0071] The second metal contact piece is used for being connected with the negative electrode of the 1.5V dry battery.

[0072] As the preferred embodiment of the utility model, the second input circuit comprises a third metal contact piece, a fourth metal contact piece, a first diode and a voltage stabilizing chip;

[0073] The third metal contact piece is connected with one end of the fifth resistor, one end of the nineteenth resistor and the positive electrode of the first diode, one end of the nineteenth resistor is connected with a 9V power supply, and the other end of the fifth resistor is connected with the input end of the control unit MCU and one end of the sixth resistor respectively;

[0074] The negative electrode of the first diode is connected with one end of an electrolytic capacitor and the input end of the voltage stabilizing chip respectively, the negative electrode of the second diode is connected with one end of the electrolytic capacitor, the output end of the voltage stabilizing chip is connected with one end of the second capacitor and one end of the fourth capacitor respectively, and one end of the fourth capacitor is connected with a 3V power supply;

[0075] The fourth metal contact piece is connected with the other end of the sixth resistor, the other end of the nineteenth resistor, the other end of the electrolytic capacitor, the other end of the second capacitor and the other end of the fourth capacitor respectively, and the grounding end of the voltage stabilizing chip is grounded;

[0076] The third metal contact piece is used for being connected with the positive electrode of a 9V dry battery;

[0077] The fourth metal contact piece is used for being connected with the negative electrode of the 9V dry battery.

[0078] As the preferred embodiment of the utility model, the first metal contact piece, the second metal contact piece, the third metal contact piece and the fourth metal contact piece are strip-shaped.

[0079] The strip-shaped piece can increase the conductivity, and can increase the sensitivity and accuracy of measurement.

[0080] As the preferred embodiment of the utility model, the other end of the first resistor is connected with the first data input end of the control unit MCU, and the other end of the fifth resistor is connected with the second data input end of the control unit MCU.

[0081] The power input end of the control unit MCU is connected with a 3V power supply, and the grounding end of the control unit MCU is grounded.

[0082] The first control display end of the control unit MCU is connected with the first control display end of the liquid crystal display.

[0083] The second control display end of the control unit MCU is connected with the second control display end of the liquid crystal display.

[0084] The third control display end of the control unit MCU is connected with the third control display end of the liquid crystal display.

[0085] The fourth control display end of the control unit MCU is connected with the fourth control display end of the liquid crystal display.

[0086] The fifth control display end of the control unit MCU is connected with the fifth control display end of the liquid crystal display.

[0087] The sixth control display end of the control unit MCU is connected with the sixth control display end of the liquid crystal display.

[0088] The seventh control display end of the control unit MCU is connected with the seventh control display end of the liquid crystal display.

[0089] The eighth control display end of the control unit MCU is connected with the eighth control display end of the liquid crystal display.

[0090] The ninth control display end of the control unit MCU is connected with the ninth control display end of the liquid crystal display.

[0091] The tenth control display end of the control unit MCU is connected with the tenth control display end of the liquid crystal display.

[0092] The eleventh control display end of the control unit MCU is connected with the eleventh control display end of the liquid crystal display.

[0093] The twelfth control display end of the control unit MCU is connected with the twelfth control display end of the liquid crystal display.

[0094] One end of the seventh resistor is connected to a 3V power supply, and the other end of the seventh resistor is connected to a first control display end of a control unit MCU, and grounded through an eighth resistor;

[0095] One end of the ninth resistor is connected to a 3V power supply, and the other end of the ninth resistor is connected to a second control display end of a control unit MCU, and grounded through a tenth resistor;

[0096] One end of the eleventh resistor is connected to a 3V power supply, and the other end of the eleventh resistor is connected to a third control display end of a control unit MCU, and grounded through a twelfth resistor;

[0097] One end of the thirteenth resistor is connected to a 3V power supply, and the other end of the thirteenth resistor is connected to a fourth control display end of a control unit MCU, and grounded through a fourteenth resistor;

[0098] One end of the fifteenth resistor is connected to a 3V power supply, and the other end of the fifteenth resistor is connected to an eighth control display end of a control unit MCU.

[0099] The output end of the micro control unit MCU is connected to a liquid crystal display screen LCD, directly displaying a test voltage and indicating a battery state (such as GOOD, LOW, Replace); when the voltage is greater than 7.8V, the liquid crystal indicates that the battery state is GOOD; when the voltage is 7.8-6.3V, the liquid crystal indicates that the battery state is LOW; when the voltage is less than 6.3V, the liquid crystal indicates that the battery state is Replace; GOOD represents good, LOW represents lower, and Replace represents too low.

[0100] In at least one embodiment, the resistance R1 is 10KΩ; R2, R6 is 20KΩ; R3 is 100KΩ; R4 is 100Ω; R5 is 115KΩ; R16 is 33Ω, and R19 is 1.2KΩ.

[0101] In at least one embodiment, the electrolytic capacitor C1 is 10u.

[0102] In at least one embodiment, the capacitor C2 is 100n, and C3 is 300p.

[0103] In at least one embodiment, the diodes D1 and D2 are IN4148.

[0104] In at least one embodiment, the inductor L1 is 300uH.

[0105] First input circuit original explanation:

[0106] 1.5V battery is connected to the circuit through the first and second metal contact pieces, and the voltage signal is biased by the sixteenth resistor (R16). The first and second resistors (R1 and R2) divide the voltage and input the first data input end (PA4) of the MCU.

[0107] The base of the first transistor (Q1) is controlled by the third resistor (R3) and the third capacitor (C3), and works with the second transistor (Q2) to dynamically adjust the signal amplification factor.

[0108] The first inductor (L1) and the third capacitor (C3) form a low-pass filter to suppress high-frequency interference in the signal.

[0109] The anode of the second diode (D2) is connected to the first inductor (L1) to prevent current from flowing back when the battery is reversed.

[0110] Second input circuit original explanation:

[0111] The 9V battery voltage is input through the third metal contact piece, rectified by the first diode (D1), and then enters the voltage stabilizing chip (U3) to output a stable 3V voltage for the MCU.

[0112] The electrolytic capacitor (C1) and the second capacitor (C2) filter out low-frequency noise at the input, and the fourth capacitor (C4) further stabilizes the 3V output.

[0113] The fifth resistor (R5) and the sixth resistor (R6) form a voltage dividing network to scale down the 9V battery voltage to the range of 0-3V, which is input to the second data input end (PA3) of the MCU.

[0114] Control unit MCU and liquid crystal display screen original explanation:

[0115] Signal processing flow:

[0116] The MCU receives signals from the 1.5V and 9V circuits through the first and second data input ends (PA4 and PA3), respectively.

[0117] If a 1.5V dry battery is measured, the display value of the liquid crystal display screen is 1.5 times the voltage value obtained by the first data input end of the control unit MCU;

[0118] If a 9V dry battery is measured, the display value of the liquid crystal display screen is 6.75 times the voltage value obtained by the second data input end of the control unit MCU;

[0119] Display driver design:

[0120] The MCU drives the liquid crystal display in a multiplexing manner through the first to twelfth control display ends (COM1-COM4, SEG1-SEG8).

[0121] The seventh resistor (R7) to the fifteenth resistor (R15) and a ground resistor (e.g., the eighth resistor (R8)) form a current-limiting voltage-division network, ensuring that each segment of the LCD uniformly lights up and is not overloaded.

[0122] In the embodiments of the present application, "at least one" means one or more, and "multiple" means two or more. The "and / or" describes the association relationship of the associated objects, indicating that there can be three relationships, for example, A and / or B, which can represent the cases of A alone, A and B together, and B alone. Wherein A and B can be singular or plural. The character " / " generally represents that the associated objects before and after are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, at least one of a, b and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0123] The above is only an embodiment of the present application, and does not limit the patent range of the present application. Any equivalent structure or equivalent process transformation using the content of the present application specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection range of the present application.

Claims

1. A voltage testing circuit for adapting to a plurality of dry cell models, characterized by, The first input circuit, the second input circuit, the control unit MCU and the liquid crystal display are connected; The output end of the first input circuit is connected with the input end of the control unit MCU, the output end of the second input circuit is connected with the input end of the control unit MCU, the output end of the control unit MCU is connected with the input end of the liquid crystal display, and the output end of the first input circuit is connected with the input end of the second input circuit; The first input circuit is used for acquiring the voltage of the 1.5V dry battery; The second input circuit is used for acquiring the voltage of the 9V dry battery; The control unit MCU is used for controlling the liquid crystal display to display the voltage measurement result of the 1.5V or 9V dry battery.

2. The voltage testing circuit for adapting to a plurality of dry cell sizes according to claim 1, wherein, The first input circuit comprises a first triode, a second triode, a first metal contact sheet and a second metal contact sheet; The first metal contact sheet is connected with one end of a first resistor, one end of a sixteenth resistor, an emitter of the first triode and one end of a first inductor respectively, one end of the sixteenth resistor is connected with a 1.5V power supply, the other end of the first resistor is connected with the input end of the control unit MCU and one end of a second resistor respectively, the base of the first triode is connected with one end of a third resistor and one end of a third capacitor respectively, the other end of the first inductor and the other end of the third capacitor are connected with the positive electrode of a second diode, and the negative electrode of the second diode is connected with the input end of the second input circuit; The second metal contact sheet is connected with the other end of the second resistor, the other end of the sixteenth resistor, the other end of the third resistor and the emitter of the second triode respectively, the other end of the third resistor is grounded, the base of the second triode is connected with the collector of the first triode through a fourth resistor, and the collector of the second triode is connected with the positive electrode of the second diode; The first metal contact sheet is used for being connected with the positive electrode of the 1.5V dry battery; The second metal contact sheet is used for being connected with the negative electrode of the 1.5V dry battery.

3. The voltage testing circuit for adapting to a plurality of dry cell sizes according to claim 2, wherein, The second input circuit comprises a third metal contact sheet, a fourth metal contact sheet, a first diode and a voltage stabilizing chip; The third metal contact sheet is connected with one end of a fifth resistor, one end of a nineteenth resistor and the positive electrode of the first diode, one end of the nineteenth resistor is connected with a 9V power supply, and the other end of the fifth resistor is connected with the input end of the control unit MCU and one end of a sixth resistor respectively; The negative electrode of the first diode is connected with one end of an electrolytic capacitor and the input end of the voltage stabilizing chip respectively, the negative electrode of the second diode is connected with one end of the electrolytic capacitor, the output end of the voltage stabilizing chip is connected with one end of a second capacitor and one end of a fourth capacitor respectively, and one end of the fourth capacitor is connected with a 3V power supply; The fourth metal contact sheet is connected with the other end of the sixth resistor, the other end of the nineteenth resistor, the other end of the electrolytic capacitor, the other end of the second capacitor and the other end of the fourth capacitor respectively, and the grounding end of the voltage stabilizing chip is grounded; The third metal contact sheet is used for being connected with the positive electrode of the 9V dry battery; The fourth metal contact sheet is used for being connected with the negative electrode of the 9V dry battery.

4. The voltage testing circuit for adapting to a plurality of dry cell sizes according to claim 3, wherein, The first metal contact sheet, the second metal contact sheet, the third metal contact sheet and the fourth metal contact sheet are in the shape of a strip.

5. The multi-size dry cell adapted voltage testing circuit according to claim 3, wherein, The other end of the first resistor is connected with the first data input end of the control unit MCU, and the other end of the fifth resistor is connected with the second data input end of the control unit MCU; The power input end of the control unit MCU is connected with a 3V power supply, and the ground end of the control unit MCU is grounded; The first control display end of the control unit MCU is connected with the first control display end of the liquid crystal display; The second control display end of the control unit MCU is connected with the second control display end of the liquid crystal display; The third control display end of the control unit MCU is connected with the third control display end of the liquid crystal display; The fourth control display end of the control unit MCU is connected with the fourth control display end of the liquid crystal display; The fifth control display end of the control unit MCU is connected with the fifth control display end of the liquid crystal display; The sixth control display end of the control unit MCU is connected with the sixth control display end of the liquid crystal display; The seventh control display end of the control unit MCU is connected with the seventh control display end of the liquid crystal display; The eighth control display end of the control unit MCU is connected with the eighth control display end of the liquid crystal display; The ninth control display end of the control unit MCU is connected with the ninth control display end of the liquid crystal display; The tenth control display end of the control unit MCU is connected with the tenth control display end of the liquid crystal display; The eleventh control display end of the control unit MCU is connected with the eleventh control display end of the liquid crystal display; The twelfth control display end of the control unit MCU is connected with the twelfth control display end of the liquid crystal display; One end of the seventh resistor is connected with the 3V power supply, and the other end of the seventh resistor is connected with the first control display end of the control unit MCU and grounded through the eighth resistor; One end of the ninth resistor is connected with the 3V power supply, and the other end of the ninth resistor is connected with the second control display end of the control unit MCU and grounded through the tenth resistor; One end of the eleventh resistor is connected with the 3V power supply, and the other end of the eleventh resistor is connected with the third control display end of the control unit MCU and grounded through the twelfth resistor; One end of the thirteenth resistor is connected with the 3V power supply, and the other end of the thirteenth resistor is connected with the fourth control display end of the control unit MCU and grounded through the fourteenth resistor; One end of the fifteenth resistor is connected with the 3V power supply, and the other end of the fifteenth resistor is connected with the eighth control display end of the control unit MCU.

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