Thumper circuit

A buzzer and circuit technology, applied to instruments, sound-generating devices, etc., can solve problems such as instability

Inactive Publication Date: 2016-05-18

HONG FU JIN PRECISION IND WUHAN CO LTD +1

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AI-Extracted Technical Summary

Problems solved by technology

[0002] The sound of the existing buzzer ...

Method used

The above-mentioned buzzer circuit 100 utilizes the triode Q and the constant voltage elements 12, 14 to keep the voltage of the second res...

Abstract

A thumper circuit is connected with a drive circuit and comprises a thumper and a control unit. The control unit comprises an electronic switch, a first resistor, a second resistor and a constant voltage element. A control end of the electronic switch is connected with a power supply pin of the thumper through the first resistor, and is also grounded through the constant voltage element. A first end of the electronic switch is connected with a grounding pin of the thumper. A second end of the electronic switch is grounded through the second resistor. When the thumper receives a high-level driving signal, the electronic switch is closed, and the voltage between the control end and the second end of the electronic switch is constant, so as to cooperate with the constant voltage element to provide a constant voltage for two ends of the second resistor, and the grounding pin of the thumper is grounded successively through the electronic switch and the second resistor. According to the thumper circuit of the present invention, the voltage of the second resistor is constant, so that the current flowing through the thumper is constant, thereby stabilizing the sound of the thumper during operation.

Application Domain

Sound producing devices

Technology Topic

Power flowConstant voltage +6

Image

Examples

Experimental program(1)

Example Embodiment

[0013] Below in conjunction with accompanying drawing and preferred embodiment the present invention is described in further detail:

[0014] Please refer to figure 1 , The first preferred embodiment of the buzzer circuit 100 of the present invention is connected to a driving circuit 200 , and the driving circuit 200 is used to drive the buzzer circuit 100 . The buzzer circuit 100 includes a control unit 10 and a buzzer 20 .

[0015] The control unit 10 includes a first resistor R1 , a second resistor R2 , a transistor Q and a constant voltage element 12 . The constant voltage element 12 includes two diodes D1 and D2 connected in series. The buzzer 20 includes a power pin VCC and a ground pin GND. The power supply pin VCC is connected to the driving circuit 200 . The base of the triode Q is connected to the power pin VCC of the buzzer 20 through the first resistor R1. The collector of the transistor Q is connected to the ground pin GND of the buzzer 20 . The emitter of the triode Q is grounded through the second resistor R2. The anode of the diode D1 is connected to the base of the transistor Q, the cathode of the diode D1 is connected to the anode of the diode D2, and the cathode of the diode D2 is grounded.

[0016] In this embodiment, when the power pin VCC is connected to a high-level signal and the ground pin GND is connected to a low-level signal, the buzzer 20 starts to work. The transistor Q is an NPN transistor.

[0017] When the driving circuit 200 sends out a high-level driving signal, the power pin VCC of the buzzer 20 receives the high-level driving signal. At the same time, the triode Q, diodes D1 and D2 are turned on, and the sum of the voltage across the second resistor R2 and the voltage between the base and emitter of the triode Q is the sum of the voltages across the diodes D1 and D2. The voltage between the base and the emitter of the triode Q is set as Vbe, the conduction voltage of the diodes D1 and D2 is VD, the resistance value of the resistor R is r, and the operating current of the buzzer 20 is I ( That is, the current flowing through the second resistor R2), then I=(2VD-Vbe)/r. Since the triode Q is turned on, the voltage Vbe between the base and the emitter of the triode Q is a constant value, so when the driving circuit 200 sends a high-level driving signal, the buzzer 20 The working current is constant, and the buzzer 20 makes a stable sound when it works.

[0018] In this embodiment, the constant voltage element 12 is used to keep the sum of the voltage across the second resistor R2 and the voltage between the base and emitter of the triode Q constant, so as to keep the voltage across the second resistor R2 constant.

[0019] see figure 2 , The constant voltage element 14 of the second preferred embodiment of the buzzer circuit 100 of the present invention includes several diodes D1, D2, . . . D(n-1), Dn connected in series, where n is an integer and n≧3. The anode of the diode D1 is connected to the base of the transistor Q, and the cathode of the diode D1 is connected to the anode of the diode D2. By analogy, the cathode of the diode D(n−1) is connected to the anode of the diode Dn, and the cathode of the diode Dn is grounded. Set the conduction voltage of diodes D1, D2, . . . D(n-1), Dn as VD. At this time, the working current of the buzzer 20 is I=(n*VD-Vbe)/r.

[0020] In other embodiments, the user can change the volume of the sound when the buzzer 20 is working by changing the resistance value of the second resistor R2.

[0021] It can be seen from the above description that the triode Q functions as an electronic switch. In other implementations, the triode Q can also be replaced by other electronic switches, wherein the base, collector and emitter of the triode correspond to The control terminal, the first terminal and the second terminal of the electronic switch.

[0022] The buzzer circuit 100 uses the triode Q and the constant voltage elements 12, 14 to keep the voltage of the second resistor constant, so as to keep the current flowing through the buzzer 20 constant, and then stabilize the buzzer 20 to work. time sound.

PUM

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