CN115798442A

CN115798442A - System and method for voice prompt when power is on

Info

Publication number: CN115798442A
Application number: CN202211413218.0A
Authority: CN
Inventors: 瞿杰
Original assignee: Shenzhen Xiaozhai Technology Co ltd
Current assignee: Shenzhen Xiaozhai Technology Co ltd
Priority date: 2022-11-11
Filing date: 2022-11-11
Publication date: 2023-03-14

Abstract

The invention relates to the technical field of sound prompt, and discloses a system and a method for sound prompt when a power supply is switched on, after a circuit is powered on, current flows from a resistor R1 and a capacitor C1 to a negative electrode of the power supply, the collector junction voltage Vbc of a triode Q1 is not enough to be reversely biased by a collector, the triode Q1 is cut off, and a buzzer is silent; the resistor R1 continuously charges the capacitor C1, the base voltage of the triode Q1 gradually rises, the collector of the triode Q1 is reversely biased, the emitter is positively biased, the triode Q1 enters an amplification state, the collector current Ic of the triode Q1 is multiplied from small to large, and the sound of the buzzer is multiplied from small to large; after the capacitor C1 is charged, the voltage rises continuously, so that the emitter base voltage Veb is insufficient, the emitter junction is biased positively, the triode Q1 is cut off, and the buzzer has no sound. The invention utilizes the resistor-capacitor component added on the base electrode of the triode to ensure that the PNP triode is changed and cut off in the amplifying area after being electrified, and drives the buzzer to realize that the sound is changed from small to big and then stops sounding.

Description

System and method for voice prompt when power is on

Technical Field

The invention relates to the technical field of buzzers, in particular to a system and a method for prompting by sound when a power supply is switched on.

Background

The buzzer is an electronic buzzer with an integrated structure, adopts direct current voltage for power supply, and is widely applied to electronic products such as computers, printers, copiers, alarms, electronic toys, automobile electronic equipment, telephones, timers and the like as a sounding device; in an electronic product which needs to make a simple prompt sound, a buzzer is also a relatively common device, and the common buzzers have two types: (1) and an active buzzer: an oscillating circuit is arranged in the circuit, and can continuously sound when direct current is supplied; (2) and a passive buzzer: the internal part of the device is not provided with an oscillating circuit, and a power supply with a certain frequency is required to be provided for sounding.

The RC circuit is a resistance-capacitance circuit, the primary RC circuit consists of a resistor and a capacitor, the RC circuit is widely applied to analog circuits and pulse digital circuits and is also suitable for driving a buzzer, and when the circuit which only produces sound in a short time is needed to be switched on, the circuit is often realized by adopting a passive buzzer and a controllable oscillating circuit, for example, an oscillating signal is output in a short time through a single chip microcomputer. The active buzzer can sound continuously because the oscillating circuit in the buzzer is uncontrollable.

When the power supply needs to be switched on, only a short-time sounding prompt is needed, the passive buzzer is driven in a universal way, and the passive buzzer is low in cost. However, the disadvantage is that the sound has no fade-in effect (fade-in effect means that the sound changes from small to large and from weak to strong, hereinafter referred to as fade-in effect), and when the sound producing part is relatively close to the human ear, the suddenly appearing sound appears very hard and not soft, and the experience feeling is very poor.

Therefore, a circuit which can generate a sound which stops after a fade-in effect through a buzzer when a power supply is switched on is an urgent problem to be solved; therefore, a system and a method for voice prompt when the power is switched on are provided.

Disclosure of Invention

The present invention is directed to a system and method for providing a voice prompt when a power is turned on, so as to solve the problems of the background art.

In order to solve the technical problems, the invention is realized by the following technical scheme:

in a first aspect, the application provides a system for voice prompt when a power supply is switched on, comprising an RC circuit and an active buzzer electrically connected with the RC circuit, wherein the RC circuit comprises a resistor R1, a capacitor C1, a resistor R2 and a triode Q1; the first end of the resistor R1 is used for being electrically connected with the positive electrode of a power supply, the first end of the capacitor C1 is used for being electrically connected with the second end of the resistor R1, and the second end of the capacitor C1 is used for being electrically connected with the negative electrode of the power supply; the triode Q1 is electrically connected with the first end of the resistor R1, the triode Q1 is also electrically connected with the first end of the active buzzer, and the second end of the active buzzer is electrically connected with the second end of the capacitor C1; the first end of the resistor R2 is electrically connected with the second end of the resistor R1, and the second end of the resistor R2 is electrically connected with the triode Q1.

Further, the RC circuit further comprises a third resistor; the first end of the third resistor is electrically connected to the first end of the capacitor C1, and the second end of the third resistor is electrically connected to the second end of the capacitor C1.

Further, the RC circuit further includes a second capacitor connected in parallel with the capacitor C1.

In a second aspect, the present application provides a method for audible prompting when a power supply is turned on, which is implemented by the aforementioned system for audible prompting when a power supply is turned on, and specifically includes the following steps:

s1: when the circuit is powered on, the current flows from the resistor R1 and the capacitor C1 to the negative electrode of a power supply, the base voltage Vb = the collector voltage Vc < the emitter voltage Ve at the moment of powering on the triode Q1, the collector junction voltage Vbc of the triode Q1 is not enough for the reverse bias of the collector, the triode Q1 is cut off, and the buzzer is silent;

s2: the resistor R1 continuously charges the capacitor C1, the base voltage of the triode Q1 gradually rises, the collector voltage Vc of the triode Q1 is less than the base voltage Vb and less than the emitter voltage Ve, the collector of the triode Q1 is reversely biased, the emitter is positively biased, the triode Q1 enters an amplification state, the collector current Ic of the triode Q1 is multiplied from small to large, and the sound of the buzzer is multiplied from small to large;

s3: after the capacitor C1 is charged, the voltage continuously rises, so that the emitter base voltage Veb is insufficient, the emitter junction is positively biased, the triode Q1 is cut off, and the buzzer has no sound.

In S1, because the voltages at two ends of the capacitor C1 cannot be suddenly changed, the capacitor C1 is regarded as a short-circuit state at the moment of electrifying, and the current limited by the resistor R1 is completely transmitted to the cathode of the power supply through the capacitor C1.

In S2, as the electric quantity of the capacitor C1 is increased, the current is reduced, the base current Ib of the triode Q1 is increased, and the collector current Ic of the triode Q1 is multiplied by small increase.

The invention has the following beneficial effects:

the system and the method for prompting the sound when the power is switched on can realize that the sound of the buzzer stops after smoothly changing from small to big by adding the resistance-capacitance component on the base electrode of the triode to ensure that the PNP triode is changed and then cut off in the amplifying area, and the sound sounds soft and not harsh, which cannot be realized by the existing circuit.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a power-on reminder circuit applied to a 5V circuit according to the present invention;

FIG. 2 is a flow chart of a method of audible prompts when powered on in accordance with the present invention;

FIG. 3 is another schematic diagram of the power-on reminder circuit applied to the 5V circuit according to the present invention;

FIG. 4 is a system circuit diagram of the audio prompt when the power is turned on according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Please refer to fig. 1-2: the application provides a system for sound prompt when a power supply is switched on, which comprises an RC circuit and an active buzzer electrically connected with the RC circuit, wherein the RC circuit comprises a resistor R1, a capacitor C1, a resistor R2 and a triode Q1; the first end of the resistor R1 is used for being electrically connected with the positive electrode of a power supply, the first end of the capacitor C1 is used for being electrically connected with the second end of the resistor R1, and the second end of the capacitor C1 is used for being electrically connected with the negative electrode of the power supply; the triode Q1 is electrically connected with the first end of the resistor R1, the triode Q1 is also electrically connected with the first end of the active buzzer, and the second end of the active buzzer is electrically connected with the second end of the capacitor C1; the first end of the resistor R2 is electrically connected with the second end of the resistor R1, and the second end of the resistor R2 is electrically connected with the triode Q1.

Referring to fig. 4, the RC circuit further includes a third resistor; the first end of the third resistor is electrically connected with the first end of the capacitor C1, and the second end of the third resistor is electrically connected with the second end of the capacitor C1.

Referring to fig. 3, the RC circuit further includes a second capacitor connected in parallel with the capacitor C1.

The application also provides a method for sound prompt when the power supply is switched on, when the circuit is powered on, the current flows from the resistor R1 and the capacitor C1 to the negative pole of the power supply, because the voltage at two ends of the capacitor C1 can not suddenly change, the capacitor C1 is regarded as a short-circuit state at the moment of power-on, and the current limited by the resistor R1 flows to the negative pole of the power supply through the capacitor C1. Vb = Vc of the triode Q1 at the moment of electrifying is less than Ve, the Vbc voltage of the triode Q1 is not enough to enable a collector to be reversely biased, the triode Q1 is cut off, and the buzzer is silent. The resistor R1 continuously charges the capacitor C1, the base voltage of the triode Q1 gradually rises, vc < Vb < Ve of the triode Q1, the collector of the triode Q1 is reversely biased, the emitter is positively biased, and the triode Q1 enters an amplification state. When the capacitor C1 is charged, the voltage continuously rises, so that the Veb voltage is insufficient, the emitting junction is positively biased, the triode Q1 is cut off, and the buzzer does not make sound.

Example 1

As shown in fig. 3, the power-on reminding circuit is applied to a 5V circuit, and when the 5V circuit is switched in, the buzzer stops sounding after sounding a sound from small to large, which is similar to a "sting".

The capacitance C2 and the capacitance C3 in the circuit can be one or more capacitances, and the tone can be changed by changing the capacitance of the capacitance and the resistance value of the resistance R4 so as to change the speed of the sound from small to large.

The triode Q2 in the circuit is a PNP type triode which can be different in type, and the amplification factor, the bias voltage value and the like of different types can change the speed of the sound from small to big.

The resistor R5 in the circuit discharges the capacitor after power failure, so that the capacitor is in a 0V state after each power failure.

The buzzer in the circuit adopts an active buzzer, and the specification is 9650.

Example 2

As shown in fig. 1, the power-on reminding circuit is applied to a 5V circuit, and when the 5V circuit is switched in, the buzzer stops sounding after emitting a sound from small to large, which is similar to a "ding" sound.

The pitch can be changed by changing the speed of the sound from small to large by changing the values of the resistor R1 and the capacitor C1 in the circuit.

The triode Q2 in the circuit is a PNP type triode which can be in different types, and the amplification factor, the bias voltage value and the like of different types can change the speed of changing the sound from small to big.

The buzzer in the circuit adopts an active buzzer, and the specification is 9650;

after the circuit is interrupted, the electric energy stored in the capacitor C1 is discharged through the resistor R1 and other load circuits connected to + 5V.

In the scheme, aiming at the problem that the existing buzzer driving mode can not send the sound from small to large, even if the passive buzzer is driven by a frequency changing mode through a single chip microcomputer and the like to realize similar effects, the sound of the buzzer can not smoothly change from small to large due to the fact that the frequency range of the passive buzzer is limited and the driving frequency is difficult to linearly change, and therefore the PNP triode is changed in an amplification area and then cut off after being powered on by adding a resistance-capacitance device on the base electrode of the triode, and the buzzer is driven to stop sounding after the sound changes from small to large.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A system for prompting sound when a power supply is switched on is characterized by comprising an RC circuit and an active buzzer electrically connected with the RC circuit, wherein the RC circuit comprises a resistor R1, a capacitor C1, a resistor R2 and a triode Q1; the first end of the resistor R1 is used for being electrically connected with the positive electrode of a power supply, the first end of the capacitor C1 is used for being electrically connected with the second end of the resistor R1, and the second end of the capacitor C1 is used for being electrically connected with the negative electrode of the power supply; the triode Q1 is electrically connected with the first end of the resistor R1, the triode Q1 is also electrically connected with the first end of the active buzzer, and the second end of the active buzzer is electrically connected with the second end of the capacitor C1; the first end of the resistor R2 is electrically connected with the second end of the resistor R1, and the second end of the resistor R2 is electrically connected with the triode Q1.

2. The system of claim 1, wherein the RC circuit further comprises a third resistor; the first end of the third resistor is electrically connected with the first end of the capacitor C1, and the second end of the third resistor is electrically connected with the second end of the capacitor C1.

3. The system of claim 2, wherein the RC circuit further comprises a second capacitor connected in parallel with the capacitor C1.

4. A method for providing audible power-on prompts, comprising the steps of:

s3: after the capacitor C1 is charged, the voltage rises continuously, so that the emitter base voltage Veb is insufficient, the emitter junction is biased positively, the triode Q1 is cut off, and the buzzer has no sound.

5. The method for prompting by sound when switching on a power supply according to claim 4, wherein in S1, because the voltage at two ends of the capacitor C1 cannot suddenly change, the capacitor C1 is regarded as a short-circuit state at the moment of power-on, and the current limited by the resistor R1 completely passes through the capacitor C1 to the negative electrode of the power supply.

6. A method as claimed in claim 5, characterized in that in S2, as the capacitance C1 rises, the current decreases, the base current Ib of the transistor Q1 increases, and the collector current Ic of the transistor Q1 increases exponentially.