CN210627415U

CN210627415U - Multifunctional buzzer alarm

Info

Publication number: CN210627415U
Application number: CN201922146126.0U
Authority: CN
Inventors: 盛开友; 邬希; 袁博; 李虎
Original assignee: Shiyan Tianyun Automobile Electric Appliance Co ltd
Current assignee: Shiyan Tianyun Automobile Electric Appliance Co ltd
Priority date: 2019-12-04
Filing date: 2019-12-04
Publication date: 2020-05-26
Anticipated expiration: 2029-12-04

Abstract

The utility model relates to a multifunctional buzzer alarm, which comprises a shell and a circuit board arranged in the shell; the circuit board is integrated with a single chip microcomputer MCU, a differential signal alarm circuit, a lifting signal alarm circuit, a power take-off signal alarm circuit, a piezoelectric buzzer circuit and a power supply circuit; the signal input end of the single chip microcomputer MCU is respectively and electrically connected with the differential signal alarm circuit, the lifting signal alarm circuit and the power take-off signal alarm circuit; the signal output end of the single chip microcomputer MCU is electrically connected with the piezoelectric buzzer circuit; the single chip microcomputer MCU is also connected with the power circuit. The utility model has the advantages of simple and reasonable design, it is with low costs, collect multi-functionally in an organic whole, can reduce the quantity of alarm, reduce the design degree of difficulty, the range of application is all right from reporting to the multichannel warning all the way, uses the reliability high, and the extending capability is strong.

Description

Multifunctional buzzer alarm

Technical Field

The utility model relates to an alarm, concretely relates to multi-functional buzzer siren.

Background

At present, the functions of an automobile are more and more complex, drivers and passengers are generally required to be reminded of paying attention to the automobile when the automobile-mounted electronic equipment is used or breaks down, the traditional buzzer (alarm) is set for single functions, such as air pressure alarm, water temperature and water level alarm, automobile lamp alarm, lifting alarm, automobile door unclosed alarm, non-fastened safety belt alarm and the like, a plurality of alarms are repeatedly configured on the automobile, the cost is increased, and the complexity of design and manufacture is brought.

Disclosure of Invention

To the problem that exists among the above-mentioned background art, the utility model provides a structural design is simple, reasonable, and is with low costs, collects multi-functionally in an organic whole, can reduce the quantity of alarm, reduces the design degree of difficulty, and the range of application is all right from reporting to the multichannel warning all the way, uses the reliability height, the multi-functional buzzer siren that the extending capability is strong.

The technical scheme of the utility model as follows:

the multifunctional buzzer alarm comprises a shell and a circuit board arranged in the shell; the circuit board is integrated with a single chip microcomputer MCU, a differential signal alarm circuit, a lifting signal alarm circuit, a power take-off signal alarm circuit, a piezoelectric buzzer circuit and a power supply circuit; the signal input end of the single chip microcomputer MCU is respectively and electrically connected with the differential signal alarm circuit, the lifting signal alarm circuit and the power take-off signal alarm circuit; the signal output end of the single chip microcomputer MCU is electrically connected with the piezoelectric buzzer circuit; the single chip microcomputer MCU is also connected with the power circuit.

The multi-functional buzzer siren, wherein: the single chip microcomputer MCU comprises a chip U1; the model of the chip U1 is MC9S08QD 4; the chip U1 passes through pin VDD and connects power VCC, through pin VSS ground connection, connects through pin PTA0 piezoelectricity buzzer circuit connects through pin PTA1 differential signal alarm circuit, connects through pin PTA2 lift signal alarm circuit connects through pin PTA3 power take-off signal alarm circuit connects through pin PTA4 pin DTA4, connects through pin PTA5 reserve alarm circuit.

The multi-functional buzzer siren, wherein: the differential signal alarm circuit is formed by connecting a triode Q3, a resistor R6, a resistor R7, a resistor R13, a capacitor C7, a switch S3 and a differential terminal J8; the triode Q3 is an NPN type triode; the collector of the triode Q3 is connected with the pin PTA1 of the chip U1, and the emitter is grounded; one end of the resistor R6 is connected with a power supply VCC, and the other end of the resistor R6 is connected with the collector of the triode Q3; one end of the capacitor C7 is grounded, and the other end of the capacitor C7 is connected with the base electrode of the triode Q3; one end of the resistor R13 is connected with the base electrode of the triode Q3, and the other end of the resistor R13 is grounded; one end of the resistor R7 is connected with the base of the triode Q3, and the other end is connected with the switch S3 and is connected with a +24V power supply through the switch S3; the differential terminal J8 is connected between the resistor R7 and the switch S3.

The multi-functional buzzer siren, wherein: the lifting signal alarm circuit is formed by connecting a triode Q4, a resistor R8, a resistor R9, a resistor R14, a capacitor C8, a switch S1, a capacitor C8 and a lifting terminal J2; the triode Q4 is an NPN type triode; the collector of the triode Q4 is connected with the pin PTA2 of the chip U1, and the emitter is grounded; one end of the resistor R8 is connected with a power supply VCC, and the other end of the resistor R8 is connected with the collector of the triode Q4; one end of the capacitor C8 is grounded, and the other end of the capacitor C8 is connected with the base electrode of the triode Q4; one end of the resistor R14 is grounded, and the other end of the resistor R14 is connected with the base electrode of the triode Q4; one end of the resistor R9 is connected with the base of the triode Q4, and the other end is connected with the switch S1 and is connected with a +24V power supply through the switch S1; the lift terminal J2 is connected between the resistor R9 and the switch S1.

The multi-functional buzzer siren, wherein: the power takeoff signal alarm circuit is formed by connecting a triode Q1, a resistor R2, a resistor R3, a resistor R11, a capacitor C5, a switch S2 and a power takeoff terminal J3; the triode Q1 is an NPN type triode; the collector of the triode Q1 is connected with the pin PTA3 of the chip U1, and the emitter is grounded; one end of the resistor R2 is connected with a power supply VCC, and the other end of the resistor R2 is connected with the collector of the triode Q1; one end of the capacitor C5 is grounded, and the other end of the capacitor C5 is connected with the base electrode of the triode Q1; one end of the resistor R11 is grounded, and the other end of the resistor R11 is connected with the base electrode of the triode Q1; one end of the resistor R3 is connected with the base of the triode Q1, and the other end is connected with the switch S2 and is connected with a +24V power supply through the switch S2; the power take-off terminal J3 is connected between the resistor R3 and the switch S2.

The multi-functional buzzer siren, wherein: the piezoelectric buzzer circuit is formed by connecting a triode Q5, an inductor L, a resistor R15, a resistor R10, a diode D1, a diode D2 and a buzzer BLZZER; the triode Q5 is an NPN type triode; one end of the resistor R15 is connected with a 24V power supply, and the other end of the resistor R15 is connected with the inductor L and is connected with the collector of the triode Q5 through the inductor L; one end of the resistor R10 is connected with the base electrode of the triode Q5, and the other end of the resistor R10 is connected with the cathode end of the diode D2; the anode end of the diode D2 is connected with a pin PTA0 of the chip U1; the emitter of the triode Q5 is grounded; the buzzer BLZZER adopts a piezoelectric buzzer or a piezoelectric ceramic buzzer, one end of the buzzer is connected with a 24V power supply, and the other end of the buzzer is connected with a collector of the triode Q5; the anode end of the diode D3 is grounded, and the cathode end is connected with the collector electrode of the triode Q5.

The multi-functional buzzer siren, wherein: a standby alarm circuit is integrated on the circuit board; the standby alarm circuit is formed by connecting a triode Q2, a resistor R4, a resistor R5, a resistor R12, a capacitor C6, a switch S4 and a standby terminal J10; the triode Q2 is an NPN type triode; the collector of the triode Q2 is connected with the pin PTA5 of the chip U1, and the emitter is grounded; one end of the resistor R4 is connected with a power supply VCC, and the other end of the resistor R4 is connected with the collector of the triode Q2; one end of the capacitor C6 is grounded, and the other end of the capacitor C6 is connected with the base electrode of the triode Q2; one end of the resistor R12 is grounded, and the other end of the resistor R12 is connected with the base electrode of the triode Q2; one end of the resistor R5 is connected with the base of the triode Q2, and the other end is connected with the switch S4 and is connected with a +24V power supply through the switch S4; the backup terminal J10 is connected between the resistor R5 and the switch S4.

The multi-functional buzzer siren, wherein: the power supply circuit is formed by connecting a chip U2, an inductor L1, a resistor R1, a diode D1, a bidirectional transient suppression diode ZD1, capacitors C1 and C3, a polar capacitor C2, a power supply terminal J1 and a ground terminal J12; the model of the chip U2 is 78L 05; the power supply terminal J1 is connected with a +24V power supply, and the ground terminal J12 is grounded; the anode end of the diode D1 is connected with a +24V power supply, and the cathode end of the diode D1 is connected with the resistor R1 and is connected to the pin Vin of the chip U2 through the resistor R1; one end of the capacitor C1 is connected with a pin Vin of the chip U2, and the other end of the capacitor C1 is grounded; one end of the inductor L1 is connected with a +5V power supply pin of the chip U2, and the other end of the inductor L1 is connected with a power supply VCC; the positive end of the polar capacitor C2 is connected with a power supply VCC, and the negative end is grounded; one end of the capacitor C3 is grounded, and the other end of the capacitor C3 is connected with a power supply VCC; one end of the bidirectional transient suppression diode ZD1 is grounded, and the other end of the bidirectional transient suppression diode ZD1 is connected with a power supply VCC.

Has the advantages that:

the utility model has the advantages of simple and reasonable design, it is with low costs, collect multi-functionally in an organic whole, can reduce the quantity of alarm, reduce the design degree of difficulty, the range of application is all the way reported to the police to the multiplex all can, also can realize audio alert, and the expansion ability is strong. At the same time. According to the invention, various alarms are integrated in one product, so that the number of electric parts on the vehicle is effectively reduced, the failure rate is reduced, and the cost is reduced; the piezoelectric buzzer circuit adopts the piezoelectric buzzer to sound, and has high reliability, light weight and strong weather environment change resistance; the single-chip microcomputer MCU can input multi-channel signals, input signals are not interfered with each other, output (alarm sound) can be set to be in multiple sounding modes, after the multi-channel alarm signal voltage is sequentially connected into the alarm, whether the signals are effective or not is judged through the single-chip microcomputer MCU, when a certain channel of signals are judged to be effective, corresponding buzzing signals are output, the sounding circuit is driven, the alarm sends different warning sounds, and alarm reasons are flexibly and easily distinguished.

Drawings

FIG. 1 is a schematic structural view of the multifunctional buzzer alarm of the present invention;

FIG. 2 is a front view of the multifunctional buzzer alarm of the present invention;

FIG. 3 is a top view of the multifunctional buzzer alarm of the present invention;

FIG. 4 is a left side view of the multifunctional buzzer alarm of the present invention;

FIG. 5 is a circuit diagram of the circuit board of the multifunctional buzzer alarm of the present invention;

fig. 6 is a working principle diagram of the multifunctional buzzer alarm of the utility model.

Detailed Description

As shown in fig. 1 to 4, the utility model discloses a multifunctional buzzer siren, including shell 1 and circuit board.

The shell 1 is a rectangular shell structure, the front surface of the shell is provided with a plug interface 11 in a matching way, the top surface is provided with a buzzer sound outlet hole 12, and the bottom side of the rear part is fixedly provided with a connecting bracket 13; the socket 11 is also provided with a cover plate in a matching way.

As shown in FIG. 5, the circuit board is installed inside the housing 1 in a matching manner, and is integrated with a single chip microcomputer MCU, a differential signal alarm circuit, a lifting signal alarm circuit, a power takeoff signal alarm circuit, a piezoelectric buzzer circuit, a standby alarm circuit and a power supply circuit.

The signal input end of the single chip microcomputer MCU is respectively and electrically connected with a lifting signal alarm circuit, a power take-off signal alarm circuit, a differential signal alarm circuit and a standby alarm circuit; the signal output end of the singlechip MCU is electrically connected with the piezoelectric buzzer circuit; the MCU is also connected with a power circuit.

As shown in fig. 5, the MCU includes a chip U1; the model of this chip U1 is flying seacalr MC9S08QD4, it connects power VCC through pin VDD, through pin VSS ground connection, connect the piezoelectricity bee calling organ circuit through pin PTA0, connect differential signal alarm circuit through pin PTA1, connect the alarm circuit of lift signal through pin PTA2, connect the alarm circuit of power takeoff signal through pin PTA3, connect pin DTA4 through pin PTA4, connect reserve alarm circuit through pin PTA 5.

As shown in FIG. 5, the differential signal alarm circuit is formed by connecting a triode Q3, a resistor R6, a resistor R7, a resistor R13, a capacitor C7, a switch S3 and a differential terminal J8. Wherein, the collector of the triode Q3 is connected with the pin PTA1 of the chip U1 of the MCU, and the emitter is grounded; one end of the resistor R6 is connected with a power supply VCC, and the other end is connected with the collector of the triode Q3; one end of the capacitor C7 is grounded, and the other end is connected with the base electrode of the triode Q3; one end of the resistor R13 is connected with the base electrode of the triode Q3, and the other end is grounded; one end of the resistor R7 is connected with the base electrode of the triode Q3, and the other end is connected with the switch S3 and is connected with a +24V power supply through the switch S3; the differential terminal J8 is connected between the resistor R7 and the switch S3; the differential terminal J8 is used for accessing a differential working signal, triggering a corresponding IO port of the MCU to become a high level, and outputting a corresponding alarm signal after processing an internal program of the MCU.

As shown in fig. 5, the lift signal alarm circuit is formed by connecting a transistor Q4, a resistor R8, a resistor R9, a resistor R14, a capacitor C8, a switch S1, a capacitor C8 and a lift terminal J2. Wherein, the collector of the triode Q4 is connected with the pin PTA2 of the chip U1 of the MCU, and the emitter is grounded; one end of the resistor R8 is connected with a power supply VCC, and the other end is connected with the collector of the triode Q4; one end of the capacitor C8 is grounded, and the other end is connected with the base electrode of the triode Q4; one end of the resistor R14 is grounded, and the other end is connected with the base electrode of the triode Q4; one end of the resistor R9 is connected with the base electrode of the triode Q4, and the other end is connected with the switch S1 and is connected with a +24V power supply through the switch S1; the lifting terminal J2 is connected between the resistor R9 and the switch S1; the lifting terminal J2 is used for being connected with a working signal of the lifter, triggering a corresponding IO port of the MCU to become high level, and outputting a corresponding alarm signal after the internal program of the MCU is processed.

As shown in fig. 5, the power takeoff signal alarm circuit is formed by connecting a triode Q1, a resistor R2, a resistor R3, a resistor R11, a capacitor C5, a switch S2 and a power takeoff terminal J3. Wherein, the collector of the triode Q1 is connected with the pin PTA3 of the chip U1 of the MCU, and the emitter is grounded; one end of the resistor R2 is connected with a power supply VCC, and the other end is connected with the collector of the triode Q1; one end of the capacitor C5 is grounded, and the other end is connected with the base electrode of the triode Q1; one end of the resistor R11 is grounded, and the other end is connected with the base electrode of the triode Q1; one end of the resistor R3 is connected with the base electrode of the triode Q1, and the other end is connected with the switch S2 and is connected with a +24V power supply through the switch S2; the power take-off terminal J3 is connected between the resistor R3 and the switch S2; the power takeoff terminal J3 is used for accessing a power takeoff working signal, triggering a corresponding IO port of the single chip microcomputer MCU to become a high level, and outputting a corresponding alarm signal after processing an internal program of the single chip microcomputer MCU.

As shown in fig. 5, the piezoelectric BUZZER circuit is formed by connecting a triode Q5, an inductor L, a resistor R15, a resistor R10, a diode D1, a diode D2 and a BUZZER. One end of the resistor R15 is connected with a 24V power supply, and the other end is connected with an inductor L and is connected with the collector of the triode Q5 through the inductor L; one end of the resistor R10 is connected with the base electrode of the triode Q5, and the other end is connected with the cathode end of the diode D2; the anode end of the diode D2 is connected with a pin PTA0 of a chip U1 of the MCU; the emitter of the transistor Q5 is grounded; the buzzer BLZZER adopts a piezoelectric ceramic buzzer, one end of the buzzer is connected with a 24V power supply, and the other end of the buzzer is connected with a collector of a triode Q5; the anode terminal of the diode D3 is grounded, and the cathode terminal is connected to the collector of the transistor Q5. When the input end of the MCU has a signal, the level of the IO port of the MCU changes from high to low, a corresponding PWM square wave is output at the OUT end, and after the PWM square wave is switched on and switched off by the triode Q5, an alarm prompt sound with specific frequency is sent OUT on the buzzer BLZZER.

As shown in fig. 5, the standby alarm circuit is formed by connecting a transistor Q2, a resistor R4, a resistor R5, a resistor R12, a capacitor C6, a switch S4 and a standby terminal J10. Wherein, the collector of the triode Q2 is connected with the pin PTA5 of the chip U1 of the MCU, and the emitter is grounded; one end of the resistor R4 is connected with a power supply VCC, and the other end is connected with the collector of the triode Q2; one end of the capacitor C6 is grounded, and the other end is connected with the base electrode of the triode Q2; one end of the resistor R12 is grounded, and the other end is connected with the base electrode of the triode Q2; one end of the resistor R5 is connected with the base electrode of the triode Q2, and the other end is connected with the switch S4 and is connected with a +24V power supply through the switch S4; the spare terminal J10 is connected between the resistor R5 and the switch S4; this reserve terminal J10 is used for inserting reserve components and parts working signal, triggers the corresponding IO mouth of singlechip MCU and becomes the high level, and corresponding alarm signal is exported after singlechip MCU internal program handles.

As shown in fig. 5, the power supply circuit includes a chip U2, an inductor L1, a resistor R1, a diode D1, a bidirectional transient suppression diode ZD1, capacitors C1 and C3, a polar capacitor C2, a power supply terminal J1, and a ground terminal J12. Wherein the model of the chip U2 is 78L 05; the power supply terminal J1 is connected to a +24V power supply, and the ground terminal J12 is grounded; the anode end of the diode D1 is connected with a +24V power supply, and the cathode end is connected with the resistor R1 and is connected to a pin Vin of a chip U2 through a resistor R1; one end of the capacitor C1 is connected with a pin Vin of the chip U2, and the other end is grounded; one end of the inductor L1 is connected with the +5V power supply pin of the chip U2, and the other end is connected with a power supply VCC; the positive terminal of the polar capacitor C2 is connected with a power supply VCC, and the negative terminal is grounded; one end of the capacitor C3 is grounded, and the other end is connected with a power supply VCC; one end of the bidirectional transient suppression diode ZD1 is grounded, and the other end is connected with a power supply VCC. The working principle of the multifunctional buzzer alarm is shown in figure 6.

The utility model has the advantages of simple and reasonable design, it is with low costs, collect multi-functionally in an organic whole, can reduce the quantity of alarm, reduce the design degree of difficulty, the range of application is all right from reporting to the multichannel warning all the way, uses the reliability high, and the extending capability is strong.

Claims

1. A multifunctional buzzer alarm comprises a shell and a circuit board arranged in the shell; the method is characterized in that: the circuit board is integrated with a single chip microcomputer MCU, a differential signal alarm circuit, a lifting signal alarm circuit, a power take-off signal alarm circuit, a piezoelectric buzzer circuit and a power supply circuit; the signal input end of the single chip microcomputer MCU is respectively and electrically connected with the differential signal alarm circuit, the lifting signal alarm circuit and the power take-off signal alarm circuit; the signal output end of the single chip microcomputer MCU is electrically connected with the piezoelectric buzzer circuit; the single chip microcomputer MCU is also connected with the power circuit.

2. A multi-functional buzzer alarm as claimed in claim 1, characterised in that: the single chip microcomputer MCU comprises a chip U1; the model of the chip U1 is MC9S08QD 4; the chip U1 passes through pin VDD and connects power VCC, through pin VSS ground connection, connects through pin PTA0 piezoelectricity buzzer circuit connects through pin PTA1 differential signal alarm circuit, connects through pin PTA2 lift signal alarm circuit connects through pin PTA3 power take-off signal alarm circuit connects through pin PTA4 pin DTA 4.

3. A multi-functional buzzer alarm as claimed in claim 2, characterised in that: the differential signal alarm circuit is formed by connecting a triode Q3, a resistor R6, a resistor R7, a resistor R13, a capacitor C7, a switch S3 and a differential terminal J8; the triode Q3 is an NPN type triode;

the collector of the triode Q3 is connected with the pin PTA1 of the chip U1, and the emitter is grounded; one end of the resistor R6 is connected with a power supply VCC, and the other end of the resistor R6 is connected with the collector of the triode Q3; one end of the capacitor C7 is grounded, and the other end of the capacitor C7 is connected with the base electrode of the triode Q3; one end of the resistor R13 is connected with the base electrode of the triode Q3, and the other end of the resistor R13 is grounded; one end of the resistor R7 is connected with the base of the triode Q3, and the other end is connected with the switch S3 and is connected with a +24V power supply through the switch S3; the differential terminal J8 is connected between the resistor R7 and the switch S3.

4. A multi-functional buzzer alarm as claimed in claim 2, characterised in that: the lifting signal alarm circuit is formed by connecting a triode Q4, a resistor R8, a resistor R9, a resistor R14, a capacitor C8, a switch S1, a capacitor C8 and a lifting terminal J2; the triode Q4 is an NPN type triode;

the collector of the triode Q4 is connected with the pin PTA2 of the chip U1, and the emitter is grounded; one end of the resistor R8 is connected with a power supply VCC, and the other end of the resistor R8 is connected with the collector of the triode Q4; one end of the capacitor C8 is grounded, and the other end of the capacitor C8 is connected with the base electrode of the triode Q4; one end of the resistor R14 is grounded, and the other end of the resistor R14 is connected with the base electrode of the triode Q4; one end of the resistor R9 is connected with the base of the triode Q4, and the other end is connected with the switch S1 and is connected with a +24V power supply through the switch S1; the lift terminal J2 is connected between the resistor R9 and the switch S1.

5. A multi-functional buzzer alarm as claimed in claim 2, characterised in that: the power takeoff signal alarm circuit is formed by connecting a triode Q1, a resistor R2, a resistor R3, a resistor R11, a capacitor C5, a switch S2 and a power takeoff terminal J3; the triode Q1 is an NPN type triode;

the collector of the triode Q1 is connected with the pin PTA3 of the chip U1, and the emitter is grounded; one end of the resistor R2 is connected with a power supply VCC, and the other end of the resistor R2 is connected with the collector of the triode Q1; one end of the capacitor C5 is grounded, and the other end of the capacitor C5 is connected with the base electrode of the triode Q1; one end of the resistor R11 is grounded, and the other end of the resistor R11 is connected with the base electrode of the triode Q1; one end of the resistor R3 is connected with the base of the triode Q1, and the other end is connected with the switch S2 and is connected with a +24V power supply through the switch S2; the power take-off terminal J3 is connected between the resistor R3 and the switch S2.

6. A multi-functional buzzer alarm as claimed in claim 2, characterised in that: the piezoelectric buzzer circuit is formed by connecting a triode Q5, an inductor L, a resistor R15, a resistor R10, a diode D1, a diode D2 and a buzzer BLZZER; the triode Q5 is an NPN type triode;

one end of the resistor R15 is connected with a 24V power supply, and the other end of the resistor R15 is connected with the inductor L and is connected with the collector of the triode Q5 through the inductor L; one end of the resistor R10 is connected with the base electrode of the triode Q5, and the other end of the resistor R10 is connected with the cathode end of the diode D2; the anode end of the diode D2 is connected with a pin PTA0 of the chip U1; the emitter of the triode Q5 is grounded; the buzzer BLZZER adopts a piezoelectric buzzer or a piezoelectric ceramic buzzer, one end of the buzzer is connected with a 24V power supply, and the other end of the buzzer is connected with a collector of the triode Q5; the anode end of the diode D3 is grounded, and the cathode end is connected with the collector electrode of the triode Q5.

7. A multi-functional buzzer alarm as claimed in claim 2, characterised in that: a standby alarm circuit is integrated on the circuit board; the standby alarm circuit is formed by connecting a triode Q2, a resistor R4, a resistor R5, a resistor R12, a capacitor C6, a switch S4 and a standby terminal J10; the triode Q2 is an NPN type triode;

the collector of the triode Q2 is connected with the pin PTA5 of the chip U1, and the emitter is grounded; one end of the resistor R4 is connected with a power supply VCC, and the other end of the resistor R4 is connected with the collector of the triode Q2; one end of the capacitor C6 is grounded, and the other end of the capacitor C6 is connected with the base electrode of the triode Q2; one end of the resistor R12 is grounded, and the other end of the resistor R12 is connected with the base electrode of the triode Q2; one end of the resistor R5 is connected with the base of the triode Q2, and the other end is connected with the switch S4 and is connected with a +24V power supply through the switch S4; the backup terminal J10 is connected between the resistor R5 and the switch S4.

8. A multi-functional buzzer alarm as claimed in claim 1, characterised in that: the power supply circuit is formed by connecting a chip U2, an inductor L1, a resistor R1, a diode D1, a bidirectional transient suppression diode ZD1, capacitors C1 and C3, a polar capacitor C2, a power supply terminal J1 and a ground terminal J12; the model of the chip U2 is 78L 05;

the power supply terminal J1 is connected with a +24V power supply, and the ground terminal J12 is grounded; the anode end of the diode D1 is connected with a +24V power supply, and the cathode end of the diode D1 is connected with the resistor R1 and is connected to the pin Vin of the chip U2 through the resistor R1; one end of the capacitor C1 is connected with a pin Vin of the chip U2, and the other end of the capacitor C1 is grounded; one end of the inductor L1 is connected with a +5V power supply pin of the chip U2, and the other end of the inductor L1 is connected with a power supply VCC; the positive end of the polar capacitor C2 is connected with a power supply VCC, and the negative end is grounded; one end of the capacitor C3 is grounded, and the other end of the capacitor C3 is connected with a power supply VCC; one end of the bidirectional transient suppression diode ZD1 is grounded, and the other end of the bidirectional transient suppression diode ZD1 is connected with a power supply VCC.