CN212905106U

CN212905106U - Automatic detection circuit of universal meter

Info

Publication number: CN212905106U
Application number: CN202021322491.9U
Authority: CN
Inventors: 巫伟武
Original assignee: Guangzhou Deken Electronics Co ltd
Current assignee: Guangzhou Deken Electronics Co ltd
Priority date: 2020-07-07
Filing date: 2020-07-07
Publication date: 2021-04-06
Anticipated expiration: 2030-07-07

Abstract

The embodiment of the utility model provides an universal meter automatic detection circuit, universal meter automatic detection circuit includes: the key module, the pen-shape metre module, the buzzer, the power supply module, the display screen module and the IC are respectively connected with the IC. The embodiment of the utility model provides a components and parts highly integrate, simplify overall structure design, the effective value of the object that awaits measuring of automatic test in the testing process and more convenient.

Description

Automatic detection circuit of universal meter

Technical Field

The utility model relates to an electron detects technical field, and more specifically says, involves an universal meter automatic check out circuit.

Background

Early multimeters used a dial of a magneto deflection pointer, the same as a classical galvanometer; analog multimeters are less accurate because both zeroing and accurate readings from the instrument panel are prone to drift; modern multimeters have been totally digitized, specifically referred to as digital multimeters, in which the measured signal is converted to a digital voltage and amplified by a digital preamplifier, and the value is then displayed directly by a digital display screen, thus avoiding parallax errors in the readings.

After the universal meter uses the keys, when the voltage of which is unknown is measured, the universal meter does not need to dial the wheel disc to the maximum voltage level like the prior art, and then gradually dial the gear number of the wheel disc according to the reading; the key is used, the voltage is shifted to a voltage gear, the multimeter measures the alternating voltage by default, the Direct Current (DC) can be displayed on the display screen by pressing the SELECT key, and the direct current voltage can be measured; if the capacitance is measured, the capacitance unit is continuously changed on the display screen until the capacitance unit of the proper test object stops and the reading is displayed.

SUMMERY OF THE UTILITY MODEL

In order to overcome the not enough of prior art, the utility model provides a universal meter automatic detection circuit aims at solving how to test in the testing process automatic and carry out the problem of effective value such as test current or voltage more conveniently.

The utility model provides a technical scheme that its technical problem adopted is: a multimeter automatic detection circuit, comprising: the key module, the pen-shape metre module, the buzzer, the power supply module, the display screen module and the IC are respectively connected with the IC.

In one aspect, the key module includes: switch K1, switch K2, switch K3, switch K4, switch K5, switch K6, resistor R16, resistor R18, resistor R19, capacitor C1, pad S1F, pad S1J, port 1 and port 2 of switch K6 are connected to IC port PT1.1 and port PT3.7, port 1 and port 2 of switch K5 are connected to IC port PT1.0 and port PT3.7, port 1 and port 2 of switch K4 are connected to IC port PT1.1 and port PT3.5, port 1 and port 2 of switch K3 are connected to IC port PT1.0 and port PT3.5, port 1 of switch K3 and port 1 of switch K3 are connected to IC port PT 1.1.1 and port PT1.0, pad 2 of switch K3 is connected to port PT2 of switch K3, resistor R3 is connected to VSS R72, resistor R72 is connected to VDD, resistor R72 is connected to resistor R3, resistor R72 is connected to resistor R72, the capacitor C1 is connected to the pad S1J.

In one aspect, the stylus module includes: a resistor R15, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R25, a resistor R26, a resistor R27, a resistor R28, a resistor R29, a resistor R30, a resistor R31, a resistor R32, a resistor R33, a resistor R38, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a diode D1, a diode D2, a diode D3, a diode D4, a diode D5, a thermistor RT1, a piezoresistor RV1, a triode Q3, a triode Q4, a fuse F1, a fuse F2, a pad S1B, a pad S1K, a pad S1I, a pad S1D, a pad S1H and a pad S1E; a resistor R24, a resistor R21, a resistor R23, a resistor R24, a resistor R21, a resistor R23 and a resistor R22 are sequentially connected in series, one end close to the resistor R24 is connected with an IC port PB1, one end close to the resistor R23 is connected with the ground in an analog mode, a connection point between the resistor R21 and the resistor R22 is connected with a mA current input end through a fuse F1, and a connection point between the resistor R22 and the resistor R23 is connected with a 10A current input end through a bonding pad S1B and a fuse F2; the diode D1 is connected in series with the diode D4 in an inverse direction, the diode D2 is connected in series with the diode D5 in an inverse direction, a connection point of the diode D1 and the diode D4 in the inverse direction in series is connected with the anode end of the diode D3, a connection point of the diode D2 and the diode D5 in the inverse direction in series is connected with the cathode end of the diode D3, a connection point of the diode D1 and the diode D2 is connected between the pad S1B and the fuse F2, and a connection point of the diode D4 and the diode D6 is simulated to be; one end of a resistor R25 is connected with an IC port PBO, the other end of the resistor R25 is sequentially connected with a pad S1K and a piezoresistor RV1 in series and then is analog-grounded, the pad S1I, a capacitor C2, a thermistor RT1, the piezoresistor RV1 and the pad S1H are sequentially connected in series, one end close to a pad S1I is analog-grounded, one end of the resistor R32 is connected with a voltage input end, and the other end of the resistor R32 is connected with an IC port PA 6; a collector of the triode Q4 is connected with a collector of the triode Q3, a base of the triode Q4 is connected with a base of the triode Q3, the collector of the triode Q4 is connected with a base, an emitter of the triode Q4 is connected with an IC port AGND, an emitter of the triode Q3 is sequentially connected with a resistor R33 and a resistor R15 through a bonding pad S1D, after the resistor R33 is connected with a resistor R15 in series, one end close to the resistor R33 is connected with a wire, and one end close to the resistor R15 is grounded in a simulation mode; the resistor R38 is connected to the IC port REFO and the port AGND through the pad S1E, and also connected to the COM input terminal, which is connected to the voltage input terminal near the resistor R38.

On one hand, the buzzer and the power supply module comprise: the circuit comprises a resistor R, a low-frequency low-power tube X, a capacitor C, a diode D, a power supply BAT, a buzzer BZ, a triode Q, a pin CN, a chip U and a pad S1, wherein a port A, a port A and a port GND of the chip U are respectively connected with a VSS end, a port VCC of the chip U is connected with a VDD end, a port SDA, a port SCL and a port WP are sequentially and respectively connected with an IC port SDA, a port SCL and a port PT1.3, one end of the pin CN is grounded, the other end of the pin CN is connected with an IC port PT1.3, one end of the resistor R is connected with the VDD end, and the; the positive electrode of the buzzer BZ1 is connected with a VDD end through a resistor R11, and the negative electrode of the buzzer BZ1 is connected with the collector electrode of a triode Q2; the base level of the triode Q2 is connected with the IC port BZ through a resistor R12, and the emitter level of the triode Q2 is connected with the VSS end; one end of the resistor R20 is connected with the IC port PB3, and the other end is grounded in an analog mode; two ends of the resistor R34 are respectively connected with the IC port PT2.1 and the port PT2.0, one end of the resistor R35 is connected with the ICP port T2.3, and the other end is connected with the VDD end; one end of a resistor R36 is connected with a VDD end, the other end of the resistor R36 is connected with an IC port VPP, a capacitor C7, a capacitor C8, a capacitor C10, a capacitor C11 and a capacitor C12 are sequentially connected with an IC port VLCD, a port VPP, a port VGG, a port VDDA and a port ACM respectively, meanwhile, a capacitor C7, a capacitor C8, a capacitor C10, a capacitor C11 and a capacitor C12 are connected with a VSS end, a power BAT1 is connected with a diode D6 in parallel, the positive pole of the power BAT1 is connected with the negative pole of the diode D6, the negative pole of the power BAT1 is connected with the positive pole of the diode D6, a capacitor C13 is connected with a capacitor C14.

In one aspect, the display screen module includes: resistor R9, resistor R10, light emitting diode LED1, light emitting diode LED2, display screen LCD1, and triode Q1, after light emitting diode LED1 and light emitting diode LED2 are connected in parallel, one end is connected to VDD through resistor R9, the other end is connected to the collector of triode Q1, the emitting stage of triode Q1 is connected to VSS, the base stage of triode Q1 is connected to IC port PT2.3 through resistor R10, display screen LCD1 pin 8, pin 9, pin 10, pin 11, pin 12, pin 13, pin 14, pin 15, pin 16, pin 17, pin 18, and pin 19 are respectively connected to IC port SEG3, port SEG4, port SEG5, port SEG5, port SEG6, port SEG7, port SEG8, port SEG9, port SEG10, port SEG11, port SEG12, and SEG 13.

The utility model has the advantages that: through having increased button function module to replace the frequent operation of rim plate in the operation, and then reached the convenient and automatic measuring effect of universal meter.

Drawings

FIG. 1 is a block diagram of an automatic test circuit diagram module of a multimeter.

FIG. 2 is a block diagram of an automatic detection circuit diagram key of a multimeter.

FIG. 3 is a block diagram of an automatic test circuit diagram of a multimeter.

FIG. 4 is a diagram of an automatic detection circuit diagram buzzer and power supply module of the multimeter.

FIG. 5 is a block diagram of a multimeter auto-detection circuit diagram display screen.

FIG. 6 is an IC diagram of a multimeter auto-detection circuit diagram.

Detailed Description

The present invention will be further explained with reference to the drawings and examples.

The conception, the specific structure, and the technical effects produced by the present invention will be clearly and completely described below in conjunction with the embodiments and the accompanying drawings to fully understand the objects, the features, and the effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and other embodiments obtained by those skilled in the art without inventive labor based on the embodiments of the present invention all belong to the protection scope of the present invention. In addition, all the connection/connection relations referred to in the patent do not mean that the components are directly connected, but mean that a better connection structure can be formed by adding or reducing connection auxiliary components according to specific implementation conditions. The utility model discloses each technical feature in the creation can the interactive combination under the prerequisite that does not contradict conflict each other.

Refer to fig. 1 to 6

Multimeter automatic checkout circuit, the multimeter that multimeter automatic checkout circuit corresponds is applied to breakdown maintenance, teaching training, mechanical detection and scientific research institution etc. multimeter automatic checkout circuit includes: the key module 101, the stylus pen module 102, the buzzer and power supply module 103, the display screen module 104 and the IC105, wherein the key module 101, the stylus pen module 102, the buzzer and power supply module 103 and the display screen module 104 are respectively connected with the IC 105.

In the embodiment of the application, the test principle is as follows: the power supply in the buzzer and the power module 103 supplies power to the whole circuit board, which is the power supply of the whole circuit system, and ensures that the test is correctly performed in the whole test process.

The test signals are input from two test ports E-COM in the meter pen module, are subjected to voltage division by peripheral R26-R31 and then enter the IC to perform analog-to-digital conversion and function switching so as to test voltage, resistance, frequency, capacitance, diode and voltage induction,

the test signal passes through two test port input signals of C-COM, can test the electric current, the signal result that reachs gets into IC inside carries out analog-to-digital conversion and enters into the display screen, show on the display screen and show corresponding reading, K1-K6 in the button module all is in the off-state, when pressing the button, K in the corresponding button module will be put through in the twinkling of an eye, IC is inside will give the instruction, accomplish corresponding test, through having increased button function module, thereby replaced the frequent operation of rim plate in the operation, and then reach universal meter automatic measure's effect.

In one aspect, the key module 101 includes: switch K1, switch K2, switch K3, switch K4, switch K5, switch K6, resistor R16, resistor R18, resistor R19, capacitor C1, pad S1F, pad S1J, port 1 and port 2 of switch K6 are connected to IC port PT1.1 and port PT3.7, port 1 and port 2 of switch K5 are connected to IC port PT1.0 and port PT3.7, port 1 and port 2 of switch K4 are connected to IC port PT1.1 and port PT3.5, port 1 and port 2 of switch K3 are connected to IC port PT1.0 and port PT3.5, port 1 of switch K3 and port 1 of switch K3 are connected to IC port PT 1.1.1 and port PT1.0, pad 2 of switch K3 are connected to port PT2 of switch K3, resistor R3 is connected to VSS R72, resistor R3, resistor R72 and capacitor C3, the capacitor C1 is connected to the pad S1J.

In the embodiment of the application, the key function module is added, and the multimeter test current, voltage, capacitance, resistance and the like are controlled by controlling the switch K1, the switch K2, the switch K3, the switch K4, the switch K5 and the switch K6 to be switched on and off, so that the switches K1, the switch K2, the switch K3, the switch K4, the switch K5 and the switch K6 are automatically controlled to test the effective values of the corresponding quantity, and the effect of quickly testing the corresponding quantity is further achieved.

In one aspect, the stylus module 102 includes: a resistor R15, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R25, a resistor R26, a resistor R27, a resistor R28, a resistor R29, a resistor R30, a resistor R31, a resistor R32, a resistor R33, a resistor R38, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a diode D1, a diode D2, a diode D3, a diode D4, a diode D5, a thermistor RT1, a piezoresistor RV1, a triode Q3, a triode Q4, a fuse F1, a fuse F2, a pad S1B, a pad S1K, a pad S1I, a pad S1D, a pad S1H and a pad S1E; a resistor R24, a resistor R21, a resistor R23, a resistor R24, a resistor R21, a resistor R23 and a resistor R22 are sequentially connected in series, one end close to the resistor R24 is connected with an IC port PB1, one end close to the resistor R23 is connected with the ground in an analog mode, a connection point between the resistor R21 and the resistor R22 is connected with a mA current input end through a fuse F1, and a connection point between the resistor R22 and the resistor R23 is connected with a 10A current input end through a bonding pad S1B and a fuse F2; the diode D1 is connected in series with the diode D4 in an inverse direction, the diode D2 is connected in series with the diode D5 in an inverse direction, a connection point of the diode D1 and the diode D4 in the inverse direction in series is connected with the anode end of the diode D3, a connection point of the diode D2 and the diode D5 in the inverse direction in series is connected with the cathode end of the diode D3, a connection point of the diode D1 and the diode D2 is connected between the pad S1B and the fuse F2, and a connection point of the diode D4 and the diode D6 is simulated to be; one end of a resistor R25 is connected with an IC port PBO, the other end of the resistor R25 is sequentially connected with a pad S1K and a piezoresistor RV1 in series and then is analog-grounded, the pad S1I, a capacitor C2, a thermistor RT1, the piezoresistor RV1 and the pad S1H are sequentially connected in series, one end close to a pad S1I is analog-grounded, one end of the resistor R32 is connected with a voltage input end, and the other end of the resistor R32 is connected with an IC port PA 6; a collector of the triode Q4 is connected with a collector of the triode Q3, a base of the triode Q4 is connected with a base of the triode Q3, the collector of the triode Q4 is connected with a base, an emitter of the triode Q4 is connected with an IC port AGND, an emitter of the triode Q3 is sequentially connected with a resistor R33 and a resistor R15 through a bonding pad S1D, after the resistor R33 is connected with a resistor R15 in series, one end close to the resistor R33 is connected with a wire, and one end close to the resistor R15 is grounded in a simulation mode; the resistor R38 is connected to the IC port REFO and the port AGND through the pad S1E, and also connected to the COM input terminal, which is connected to the voltage input terminal near the resistor R38.

On the one hand, the buzzer and power supply module 103 includes: the circuit comprises a resistor R, a low-frequency low-power tube X, a capacitor C, a diode D, a power supply BAT, a buzzer BZ, a triode Q, a pin CN, a chip U and a pad S1, wherein a port A, a port A and a port GND of the chip U are respectively connected with a VSS end, a port VCC of the chip U is connected with a VDD end, a port SDA, a port SCL and a port WP are sequentially and respectively connected with an IC port SDA, a port SCL and a port PT1.3, one end of the pin CN is grounded, the other end of the pin CN is connected with an IC port PT1.3, one end of the resistor R is connected with the VDD end, and the; the positive electrode of the buzzer BZ1 is connected with a VDD end through a resistor R11, and the negative electrode of the buzzer BZ1 is connected with the collector electrode of a triode Q2; the base level of the triode Q2 is connected with the IC port BZ through a resistor R12, and the emitter level of the triode Q2 is connected with the VSS end; one end of the resistor R20 is connected with the IC port PB3, and the other end is grounded in an analog mode; two ends of the resistor R34 are respectively connected with the IC port PT2.1 and the port PT2.0, one end of the resistor R35 is connected with the ICP port T2.3, and the other end is connected with the VDD end; one end of a resistor R36 is connected with a VDD end, the other end of the resistor R36 is connected with an IC port VPP, a capacitor C7, a capacitor C8, a capacitor C10, a capacitor C11 and a capacitor C12 are sequentially connected with an IC port VLCD, a port VPP, a port VGG, a port VDDA and a port ACM respectively, meanwhile, a capacitor C7, a capacitor C8, a capacitor C10, a capacitor C11 and a capacitor C12 are connected with a VSS end, a power BAT1 is connected with a diode D6 in parallel, the positive pole of the power BAT1 is connected with the negative pole of the diode D6, the negative pole of the power BAT1 is connected with the positive pole of the diode D6, a capacitor C13 is connected with a capacitor C14.

In the examples of the present application. Buzzer and power module press HOLD key more than 2 seconds under the dark surrounds, can light screen backlight, are convenient for detect under night or the darker condition of light.

In one aspect, the display module 104 includes: resistor R9, resistor R10, light emitting diode LED1, light emitting diode LED2, display screen LCD1, and triode Q1, after light emitting diode LED1 and light emitting diode LED2 are connected in parallel, one end is connected to VDD through resistor R9, the other end is connected to the collector of triode Q1, the emitting stage of triode Q1 is connected to VSS, the base stage of triode Q1 is connected to IC port PT2.3 through resistor R10, display screen LCD1 pin 8, pin 9, pin 10, pin 11, pin 12, pin 13, pin 14, pin 15, pin 16, pin 17, pin 18, and pin 19 are respectively connected to IC port SEG3, port SEG4, port SEG5, port SEG5, port SEG6, port SEG7, port SEG8, port SEG9, port SEG10, port SEG11, port SEG12, and SEG 13.

While the preferred embodiments of the present invention have been described, the present invention is not limited to the above embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and such equivalent modifications or substitutions are intended to be included within the scope of the present invention as defined by the appended claims.

Claims

1. A multimeter automatic detection circuit, comprising: the key module, the pen-shape metre module, the buzzer, the power supply module, the display screen module and the IC are respectively connected with the IC.

2. The multimeter automatic detection circuit according to claim 1, wherein the key module comprises: switch K1, switch K2, switch K3, switch K4, switch K5, switch K6, resistor R16, resistor R18, resistor R19, capacitor C1, pad S1F, pad S1J, port 1 of switch K6, the port 2 is connected with an IC port PT1.1 and a port PT3.7 respectively, the port 1 and the port 2 of the switch K5 are connected with an IC port PT1.0 and a port PT3.7 respectively, the port 1 and the port 2 of the switch K4 are connected with an IC port PT1.1 and a port PT3.5 respectively, the port 1 and the port 2 of the switch K3 are connected with an IC port PT1.0 and a port PT3.5 respectively, the port 1 of the switch K2 and the port 1 of the switch K1 are connected with an IC port PT1.1 and a port PT1.0 respectively in sequence, the port 2 of the switch K2 is connected with a port 2 of a switch K1, one end of the resistor R19 and the resistor R16 after being connected in series is connected with a VSS end, the other end of the IC port PT3.6, a connection point between the resistor R19 and a resistor R16 is connected with a capacitor C1 and a resistor R18 respectively, the resistor R18 is connected with a pad S1 36.

3. The multimeter automatic detection circuit of claim 1, wherein the stylus module comprises: a resistor R15, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R25, a resistor R26, a resistor R27, a resistor R28, a resistor R29, a resistor R30, a resistor R31, a resistor R32, a resistor R33, a resistor R38, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a diode D1, a diode D2, a diode D3, a diode D4, a diode D5, a thermistor RT1, a piezoresistor RV1, a triode Q3, a triode Q4, a fuse F1, a fuse F2, a pad S1B, a pad S1K, a pad S1I, a pad S1D, a pad S1H and a pad S1E; a resistor R24, a resistor R21, a resistor R23, a resistor R24, a resistor R21, a resistor R23 and a resistor R22 are sequentially connected in series, one end close to the resistor R24 is connected with an IC port PB1, one end close to the resistor R23 is connected with the ground in an analog mode, a connection point between the resistor R21 and the resistor R22 is connected with a mA current input end through a fuse F1, and a connection point between the resistor R22 and the resistor R23 is connected with a 10A current input end through a bonding pad S1B and a fuse F2; the diode D1 is connected in series with the diode D4 in an inverse direction, the diode D2 is connected in series with the diode D5 in an inverse direction, a connection point of the diode D1 and the diode D4 in the inverse direction in series is connected with the anode end of the diode D3, a connection point of the diode D2 and the diode D5 in the inverse direction in series is connected with the cathode end of the diode D3, a connection point of the diode D1 and the diode D2 is connected between the pad S1B and the fuse F2, and a connection point of the diode D4 and the diode D6 is simulated to be; one end of a resistor R25 is connected with an IC port PBO, the other end of the resistor R25 is sequentially connected with a pad S1K and a piezoresistor RV1 in series and then is analog-grounded, the pad S1I, a capacitor C2, a thermistor RT1, the piezoresistor RV1 and the pad S1H are sequentially connected in series, one end close to a pad S1I is analog-grounded, one end of the resistor R32 is connected with a voltage input end, and the other end of the resistor R32 is connected with an IC port PA 6; a collector of the triode Q4 is connected with a collector of the triode Q3, a base of the triode Q4 is connected with a base of the triode Q3, the collector of the triode Q4 is connected with a base, an emitter of the triode Q4 is connected with an IC port AGND, an emitter of the triode Q3 is sequentially connected with a resistor R33 and a resistor R15 through a bonding pad S1D, after the resistor R33 is connected with a resistor R15 in series, one end close to the resistor R33 is connected with a wire, and one end close to the resistor R15 is grounded in a simulation mode; the resistor R38 is connected to the IC port REFO and the port AGND through the pad S1E, and also connected to the COM input terminal, which is connected to the voltage input terminal near the resistor R38.

4. The multimeter automatic detection circuit according to claim 1, wherein the buzzer and power supply module comprises: the circuit comprises a resistor R, a low-frequency low-power tube X, a capacitor C, a diode D, a power supply BAT, a buzzer BZ, a triode Q, a pin CN, a chip U and a pad S1, wherein a port A, a port A and a port GND of the chip U are respectively connected with a VSS end, a port VCC of the chip U is connected with a VDD end, a port SDA, a port SCL and a port WP are sequentially and respectively connected with an IC port SDA, a port SCL and a port PT1.3, one end of the pin CN is grounded, the other end of the pin CN is connected with an IC port PT1.3, one end of the resistor R is connected with the VDD end, and the; the positive electrode of the buzzer BZ1 is connected with a VDD end through a resistor R11, and the negative electrode of the buzzer BZ1 is connected with the collector electrode of a triode Q2; the base level of the triode Q2 is connected with the IC port BZ through a resistor R12, and the emitter level of the triode Q2 is connected with the VSS end; one end of the resistor R20 is connected with the IC port PB3, and the other end is grounded in an analog mode; two ends of the resistor R34 are respectively connected with the IC port PT2.1 and the port PT2.0, one end of the resistor R35 is connected with the ICP port T2.3, and the other end is connected with the VDD end; one end of a resistor R36 is connected with a VDD end, the other end of the resistor R36 is connected with an IC port VPP, a capacitor C7, a capacitor C8, a capacitor C10, a capacitor C11 and a capacitor C12 are sequentially connected with an IC port VLCD, a port VPP, a port VGG, a port VDDA and a port ACM respectively, meanwhile, a capacitor C7, a capacitor C8, a capacitor C10, a capacitor C11 and a capacitor C12 are connected with a VSS end, a power BAT1 is connected with a diode D6 in parallel, the positive pole of the power BAT1 is connected with the negative pole of the diode D6, the negative pole of the power BAT1 is connected with the positive pole of the diode D6, a capacitor C13 is connected with a capacitor C14.

5. The multimeter automatic detection circuit of claim 1, wherein the display screen module comprises: resistor R9, resistor R10, light emitting diode LED1, light emitting diode LED2, display screen LCD1, and triode Q1, after light emitting diode LED1 and light emitting diode LED2 are connected in parallel, one end is connected to VDD through resistor R9, the other end is connected to the collector of triode Q1, the emitting stage of triode Q1 is connected to VSS, the base stage of triode Q1 is connected to IC port PT2.3 through resistor R10, display screen LCD1 pin 8, pin 9, pin 10, pin 11, pin 12, pin 13, pin 14, pin 15, pin 16, pin 17, pin 18, and pin 19 are respectively connected to IC port SEG3, port SEG4, port SEG5, port SEG5, port SEG6, port SEG7, port SEG8, port SEG9, port SEG10, port SEG11, port SEG12, and SEG 13.