Amplitude-adjustable audio playing device

Abstract

The utility model discloses audio playing equipment with adjustable amplitude. The audio playing equipment comprises a potentiometer, a microprocessor unit, a resistance detection unit, a signal gain unit and an audio output unit, the potentiometer is used for adjusting the audio amplitude played by the audio playing equipment, the potentiometer is connected with the microprocessor unit, the resistance detection unit is used for detecting the total resistance value of the potentiometer, the resistance detection unit is connected with the microprocessor unit, the microprocessor unit is connected with the signal gain unit, and the signal gain unit is connected with the audio output unit; the microprocessor unit is used for receiving an input audio signal, the signal gain unit is used for performing signal gain processing on the audio signal, and the audio output unit is used for playing the audio signal after signal gain processing. According to the audio playing equipment, the accuracy of audio signal output can be improved, so that the use experience of a user is improved. The method can be widely applied to the technical field of playing equipment.

Description

Technical Field

[0001] This application relates to the field of playback device technology, and in particular to an adjustable amplitude audio playback device. Background Technology

[0002] With technological advancements, the functionality and performance of audio playback devices have continuously improved, leading to their increasingly widespread application in daily life, education, and commerce. Audio playback devices convert electrical signals into sound signals, providing us with music, voice, and other audio playback applications. Some audio playback devices incorporate potentiometers, which are variable resistors used to adjust the amplitude of the audio signal, i.e., the volume. For example, some potentiometers are designed as knobs, allowing users to adjust the audio amplitude by turning the knob.

[0003] In related technologies, due to limitations in the manufacturing process, the precision of potentiometers in current audio playback devices often has some deviation, meaning the actual resistance value does not match the designed resistance value. When users adjust the audio signal amplitude by manipulating the potentiometer, the adjusted volume will deviate from the designed output amplitude, resulting in inaccurate audio signal output and negatively impacting the user experience.

[0004] In summary, the problems with the relevant technologies urgently need to be addressed. Utility Model Content

[0005] The purpose of this application is to at least partially solve one of the technical problems existing in the related art.

[0006] Therefore, one object of the embodiments of this application is to provide an audio playback device with adjustable amplitude.

[0007] To achieve the above-mentioned technical objectives, the technical solutions adopted in the embodiments of this application include:

[0008] On one hand, embodiments of this application provide an adjustable amplitude audio playback device, including:

[0009] Potentiometer, microprocessor unit, resistor detection unit, signal gain unit, and audio output unit;

[0010] The potentiometer is used to adjust the amplitude of the audio played by the audio playback device. The potentiometer is connected to the microprocessor unit. The resistance detection unit is used to detect the total resistance of the potentiometer. The resistance detection unit is connected to the microprocessor unit. The microprocessor unit is connected to the signal gain unit. The signal gain unit is connected to the audio output unit.

[0011] The microprocessor unit is used to receive the input audio signal, the signal gain unit is used to perform signal gain processing on the audio signal, and the audio output unit is used to play the signal gain processed audio signal.

[0012] In addition, an adjustable-amplitude audio playback device according to the above embodiments of this application may also have the following additional technical features:

[0013] Furthermore, in one embodiment of this application, the adjustable amplitude audio playback device further includes a power supply unit, which provides power to the potentiometer, the microprocessor unit, the resistance detection unit, the signal gain unit, and the audio output unit.

[0014] Furthermore, in one embodiment of this application, the power supply unit includes a rechargeable battery.

[0015] Furthermore, in one embodiment of this application, the microprocessor unit includes a BP1048 chip, a digital signal processor chip, or an LMV331 chip.

[0016] Furthermore, in one embodiment of this application, the audio playback device further includes a memory storing the design resistance value of the potentiometer, and the memory is connected to the microprocessor unit.

[0017] Furthermore, in one embodiment of this application, the audio output unit includes a speaker.

[0018] Furthermore, in one embodiment of this application, the audio playback device further includes an upper and lower threshold triggering unit, which is connected to the microprocessor unit.

[0019] Furthermore, in one embodiment of this application, the upper and lower threshold triggering units include a differential signal attenuation circuit, an upper limit triggering circuit, and a lower limit triggering circuit;

[0020] The differential signal attenuation circuit is used to receive the input audio signal. The differential signal attenuation circuit is connected to the upper limit trigger circuit and the lower limit trigger circuit. The output terminal of the upper limit trigger circuit is connected to the first pin of the microprocessor unit, and the output terminal of the lower limit trigger circuit is connected to the second pin of the microprocessor unit.

[0021] Furthermore, in one embodiment of this application, the differential signal attenuation circuit includes a fifth capacitor, a seventh capacitor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a third operational amplifier, and a sixth capacitor;

[0022] The fifth capacitor is connected to the non-inverting input of the third operational amplifier through the twelfth resistor. The seventh capacitor is connected to the inverting input of the third operational amplifier through the thirteenth resistor. The output of the third operational amplifier is connected to the inverting input of the third operational amplifier through the fourteenth resistor. The output of the third operational amplifier is also connected to the first terminal of the sixth capacitor. The second terminal of the sixth capacitor is connected to the upper limit trigger circuit and the lower limit trigger circuit.

[0023] Furthermore, in one embodiment of this application, the lower limit trigger circuit includes a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a second operational amplifier, a third diode, a fourth diode, and a fourth capacitor;

[0024] The positive terminal of the third diode is connected to the second terminal of the sixth capacitor, and the negative terminal of the third diode is connected to the first terminal of the ninth resistor and the first terminal of the tenth resistor. The second terminal of the ninth resistor is connected to the inverting input terminal of the second operational amplifier. The second terminal of the ninth resistor is also grounded through the fourth capacitor. The second terminal of the tenth resistor is grounded. The positive terminal of the fourth diode is grounded, and the negative terminal of the fourth diode is connected to the second terminal of the sixth capacitor. The non-inverting input terminal of the second operational amplifier is grounded through the eighth resistor. The non-inverting input terminal of the second operational amplifier is also connected to the power supply through the sixth resistor. The output terminal of the second operational amplifier is connected to the power supply through the seventh resistor. The output terminal of the second operational amplifier is also connected to the second pin of the microprocessor unit.

[0025] The advantages and beneficial effects of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application:

[0026] This application discloses an adjustable amplitude audio playback device, which includes a potentiometer, a microprocessor unit, a resistance detection unit, a signal gain unit, and an audio output unit. The potentiometer is used to adjust the amplitude of the audio played by the playback device. The potentiometer is connected to the microprocessor unit. The resistance detection unit is used to detect the total resistance of the potentiometer and is connected to the microprocessor unit. The microprocessor unit is connected to the signal gain unit, and the signal gain unit is connected to the audio output unit. The microprocessor unit receives an input audio signal, the signal gain unit performs signal gain processing on the audio signal, and the audio output unit plays the signal-gain-processed audio signal. The audio playback device of this application can adjust the amplitude of the output audio signal correspondingly through the signal gain unit based on the detection of the potentiometer's resistance value, thereby matching the output performance of the audio playback device with its design parameters, improving the accuracy of the audio signal output, and thus enhancing the user experience. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following description is provided with accompanying drawings of the relevant technical solutions in the embodiments of this application or the prior art. It should be understood that the accompanying drawings described below are only for the purpose of clearly illustrating some embodiments of the technical solutions of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0028] Figure 1 A schematic diagram of the structure of an adjustable amplitude audio playback device provided in an embodiment of this application is shown;

[0029] Figure 2 The diagram shows a circuit schematic of an upper and lower threshold triggering unit provided in an embodiment of this application. Detailed Implementation

[0030] The present application will be further described below with reference to the accompanying drawings and specific embodiments. The described embodiments should not be considered as limitations on the present application, and all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present application.

[0031] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0032] In the description of this application, it should be understood that the terms "length," "upper," "lower," "front," "rear," "left," "right," "top," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0033] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0034] With technological advancements, the functionality and performance of audio playback devices have continuously improved, leading to their increasingly widespread application in daily life, education, and commerce. Audio playback devices convert electrical signals into sound signals, providing us with music, voice, and other audio playback applications. Some audio playback devices incorporate potentiometers, which are variable resistors used to adjust the amplitude of the audio signal, i.e., the volume. For example, some potentiometers are designed as knobs, allowing users to adjust the audio amplitude by turning the knob.

[0035] In related technologies, due to limitations in the manufacturing process, the precision of potentiometers in current audio playback devices often has some deviation, meaning the actual resistance value does not match the designed resistance value. When users adjust the audio signal amplitude by manipulating the potentiometer, the adjusted volume will deviate from the designed output amplitude, resulting in inaccurate audio signal output and negatively impacting the user experience.

[0036] In view of this, this application provides an adjustable amplitude audio playback device, which includes a potentiometer, a microprocessor unit, a resistance detection unit, a signal gain unit, and an audio output unit. The potentiometer is used to adjust the amplitude of the audio played by the audio playback device. The potentiometer is connected to the microprocessor unit. The resistance detection unit is used to detect the total resistance of the potentiometer and is connected to the microprocessor unit. The microprocessor unit is connected to the signal gain unit, and the signal gain unit is connected to the audio output unit. The microprocessor unit receives the input audio signal, the signal gain unit performs signal gain processing on the audio signal, and the audio output unit plays the signal-gain-processed audio signal. The audio playback device of this application can adjust the amplitude of the output audio signal correspondingly through the signal gain unit based on the detection of the potentiometer's resistance value, thus matching the output performance of the audio playback device with its design parameters, improving the accuracy of the audio signal output, and thereby enhancing the user experience.

[0037] The adjustable amplitude audio playback device provided in the embodiments of this application will now be described in detail with reference to the specific accompanying drawings.

[0038] This application provides an adjustable amplitude audio playback device, which can be applied to the field of playback device technology. Specifically, the adjustable amplitude audio playback device provided in this application mainly includes:

[0039] Potentiometer, microprocessor unit, resistor detection unit, signal gain unit, and audio output unit;

[0040] The potentiometer is used to adjust the amplitude of the audio played by the audio playback device. The potentiometer is connected to the microprocessor unit. The resistance detection unit is used to detect the total resistance of the potentiometer. The resistance detection unit is connected to the microprocessor unit. The microprocessor unit is connected to the signal gain unit. The signal gain unit is connected to the audio output unit.

[0041] The microprocessor unit is used to receive the input audio signal, the signal gain unit is used to perform signal gain processing on the audio signal, and the audio output unit is used to play the signal gain processed audio signal.

[0042] In this embodiment of the application, an adjustable amplitude audio playback device is provided. Based on the detection of the resistance value of the potentiometer, the amplitude of the output audio signal is adjusted accordingly by the signal gain unit, so that the output performance of the audio playback device matches the design parameters, which can improve the accuracy of the audio signal output and thus improve the user experience.

[0043] Specifically, please refer to Figure 1 , Figure 1 This illustration shows a structural diagram of an audio playback device provided in an embodiment of this application. In this embodiment, the audio playback device may include a potentiometer, a microprocessor unit, a resistance detection unit, a signal gain unit, and an audio output unit. The potentiometer can be used to adjust the amplitude of the audio signal played by the audio playback device. A potentiometer is a commonly used adjustable resistive element used to adjust voltage or current in a circuit. In an audio playback device, the potentiometer can be used to adjust the amplitude (i.e., volume) of the audio signal. A potentiometer generally consists of a resistive element and a sliding contact. The sliding contact can move on the resistive element, thereby changing the resistance value. When the sliding contact is located at one end of the resistive element, the output voltage is close to zero, and the volume is minimum. When the sliding contact is located at the other end of the resistive element, the output voltage is close to the input voltage, and the volume is maximum. For example, the potentiometer may include a knob. By rotating the potentiometer knob, the user can change the position of the sliding contact, thereby adjusting the output voltage and adjusting the volume.

[0044] The microprocessor unit is the main control device of the adjustable amplitude audio playback device. For example, in some embodiments, the microprocessor unit may include a BP1048 chip, a digital signal processor chip, or an LMV331 chip. In the embodiments of this application, there is no limitation on the specific chip type included in the microprocessor unit, and it can be flexibly selected as needed.

[0045] In this embodiment, the audio playback device includes a resistance detection unit, which is mainly used to detect the total resistance of the potentiometer. For example, the resistance detection unit can detect the voltage across the potentiometer and calculate its total resistance using the voltage divider principle. In this embodiment, the specific type of device used for the resistance detection unit is not limited. The resistance detection unit is connected to a microprocessor unit and can transmit the detected total resistance of the potentiometer to the microprocessor unit. The microprocessor unit can pre-store the design resistance value of the potentiometer. Specifically, in some embodiments, the audio playback device may also include a memory, which can store the design resistance value of the potentiometer. The microprocessor unit is connected to the memory and can retrieve the design resistance value of the potentiometer from the memory. Of course, it should be noted that the memory in this embodiment may also store other data, such as audio data, etc., and this application does not impose any limitations on this.

[0046] Within the microprocessor unit, the total resistance of the potentiometer is compared with its designed resistance to determine the gain ratio of the signal gain unit. Specifically, the microprocessor unit can include a comparator whose input can be a voltage value converted from the potentiometer's designed resistance. The total resistance of the potentiometer is also converted to a voltage value for comparison. If the voltage value is too high or too low, the gain can be adjusted proportionally by the signal gain unit. Thus, even if there are deviations in the potentiometer's accuracy, resulting in a mismatch between the actual and designed resistance, the signal gain unit can appropriately correct these deviations, improving the accuracy of the audio signal output.

[0047] Specifically, in this embodiment, the audio signal can be input to the microprocessor unit. Based on the total resistance of the potentiometer detected by the resistance detection unit and the designed resistance value, the microprocessor unit can determine the corresponding gain, thereby controlling the signal gain unit to perform signal gain processing on the audio signal. The signal gain-processed audio signal is then further transmitted to the audio output unit for playback. The audio output unit can employ components such as a speaker; this application does not impose any limitations on this.

[0048] It is understood that the audio playback device provided in this application embodiment can adjust the amplitude of the output audio signal by means of the signal gain unit based on the detection of the resistance value of the potentiometer, so that the output performance of the audio playback device matches the design parameters, thereby improving the accuracy of the audio signal output and thus improving the user experience.

[0049] In some embodiments, the adjustable amplitude audio playback device further includes a power supply unit for providing power to the potentiometer, the microprocessor unit, the resistance detection unit, the signal gain unit, and the audio output unit.

[0050] In this embodiment of the application, a power supply unit may be provided in the adjustable amplitude audio playback device. The power supply unit can provide power to other devices. For example, the power supply unit may include a rechargeable battery, but this application does not limit this.

[0051] In some embodiments, the audio playback device further includes upper and lower threshold triggering units, which are connected to the microprocessor unit.

[0052] In this embodiment, the adjustable amplitude audio playback device may further include upper and lower threshold trigger units. These units are connected to the microprocessor unit and can be used to limit the played audio signal to within a set amplitude threshold. Specifically, in this embodiment, an upper and lower amplitude limit can be preset. When the audio signal is greater than the lower amplitude limit and less than the upper amplitude limit, it is considered normal, and the output meets the requirements. When the audio signal is less than the lower amplitude limit, the microprocessor unit can control the signal gain unit to appropriately increase the gain, thereby increasing the amplitude of the output audio signal. When the audio signal is greater than the upper amplitude limit, the microprocessor unit can control the signal gain unit to appropriately decrease the gain, thereby reducing the amplitude of the output audio signal.

[0053] Specifically, please refer to Figure 2 , Figure 2 The diagram shows a circuit diagram of an upper and lower threshold triggering unit provided in an embodiment of this application. In this embodiment, the upper and lower threshold triggering unit includes a differential signal attenuation circuit, an upper limit triggering circuit, and a lower limit triggering circuit. The differential signal attenuation circuit is used to receive the input audio signal and is connected to both the upper and lower limit triggering circuits. The output of the upper limit triggering circuit is connected to a first pin of the microprocessor unit, and the output of the lower limit triggering circuit is connected to a second pin of the microprocessor unit.

[0054] like Figure 2 As shown, the differential signal attenuation circuit includes a fifth capacitor C5, a seventh capacitor C7, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a third operational amplifier U3A, and a sixth capacitor C6. The fifth capacitor C5 is connected to the non-inverting input of the third operational amplifier U3A through the twelfth resistor R12. The seventh capacitor C7 is connected to the inverting input of the third operational amplifier U3A through the thirteenth resistor R13. The output of the third operational amplifier U3A is connected to the inverting input of the third operational amplifier U3A through the fourteenth resistor R14. The output of the third operational amplifier U3A is also connected to the first terminal of the sixth capacitor C6. The second terminal of the sixth capacitor C6 is connected to the upper limit trigger circuit and the lower limit trigger circuit.

[0055] In this embodiment, the fifth capacitor C5, the seventh capacitor C7, the twelfth resistor R12, the thirteenth resistor R13, the fourteenth resistor R14, the third operational amplifier U3A, and the sixth capacitor C6 constitute a differential signal attenuation circuit to convert a larger voltage signal into a smaller voltage signal. The sixth capacitor C6 is a coupling capacitor that outputs the converted signal to the upper limit trigger circuit and the lower limit trigger circuit for corresponding comparison.

[0056] Specifically, taking the lower limit trigger circuit as an example, it includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a second operational amplifier U2A, a third diode D3, a fourth diode D4, and a fourth capacitor C4.

[0057] The positive terminal of the third diode D3 is connected to the second terminal of the sixth capacitor C6, and the negative terminal of the third diode D3 is connected to the first terminal of the ninth resistor R9 and the first terminal of the tenth resistor R10. The second terminal of the ninth resistor R9 is connected to the inverting input terminal of the second operational amplifier U2A. The second terminal of the ninth resistor R9 is also grounded through the fourth capacitor C4, the second terminal of the tenth resistor R10 is grounded, the positive terminal of the fourth diode D4 is grounded, and the negative terminal of the fourth diode D4 is connected to the second terminal of the sixth capacitor C6. The non-inverting input terminal of the second operational amplifier U2A is grounded through the eighth resistor R8, and the non-inverting input terminal of the second operational amplifier U2A is also connected to the power supply through the sixth resistor R6. The output terminal of the second operational amplifier U2A is connected to the power supply through the seventh resistor R7, and the output terminal of the second operational amplifier U2A is also connected to the second pin of the microprocessor unit.

[0058] In this embodiment, the third diode D3, the fourth diode D4, the ninth resistor R9, the tenth resistor R10, and the fourth capacitor C4 constitute a signal rectifier circuit. The second operational amplifier U2A is a comparator. By adjusting the resistance value of the eighth resistor R8, the lower limit amplitude can be set. After comparing the signal with the second operational amplifier U2A, a high or low level can be output. When the second operational amplifier U2A outputs a low level, it indicates that the audio signal is less than the lower limit amplitude. At this time, the second pin of the microprocessor unit receives this level signal and controls the signal gain unit to reduce the gain. Similarly, the structure and working principle of the upper limit trigger circuit are similar to those of the lower limit trigger circuit, and will not be described in detail here.

[0059] In the description of this specification, references to terms such as "one embodiment," "another embodiment," or "some embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0060] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An adjustable amplitude audio playback device, characterized in that, include: Potentiometer, microprocessor unit, resistor detection unit, signal gain unit, and audio output unit; The potentiometer is used to adjust the amplitude of the audio played by the audio playback device. The potentiometer is connected to the microprocessor unit. The resistance detection unit is used to detect the total resistance of the potentiometer. The resistance detection unit is connected to the microprocessor unit. The microprocessor unit is connected to the signal gain unit. The signal gain unit is connected to the audio output unit. The microprocessor unit is used to receive the input audio signal, the signal gain unit is used to perform signal gain processing on the audio signal, and the audio output unit is used to play the signal gain processed audio signal.

2. The adjustable amplitude audio playback device according to claim 1, characterized in that, The adjustable-amplitude audio playback device further includes a power supply unit for providing power to the potentiometer, the microprocessor unit, the resistance detection unit, the signal gain unit, and the audio output unit.

3. The adjustable amplitude audio playback device according to claim 2, characterized in that, The power unit includes a rechargeable battery.

4. An adjustable amplitude audio playback device according to any one of claims 1-3, characterized in that, The microprocessor unit includes a BP1048 chip, a digital signal processor chip, or an LMV331 chip.

5. The adjustable amplitude audio playback device according to claim 1, characterized in that, The audio playback device further includes a memory that stores the design resistance value of the potentiometer, and the memory is connected to the microprocessor unit.

6. The adjustable amplitude audio playback device according to claim 1, characterized in that, The audio output unit includes a speaker.

7. The adjustable amplitude audio playback device according to claim 1, characterized in that, The audio playback device further includes upper and lower threshold triggering units, which are connected to the microprocessor unit.

8. The adjustable amplitude audio playback device according to claim 7, characterized in that, The upper and lower threshold triggering units include a differential signal attenuation circuit, an upper limit triggering circuit, and a lower limit triggering circuit; The differential signal attenuation circuit is used to receive the input audio signal. The differential signal attenuation circuit is connected to the upper limit trigger circuit and the lower limit trigger circuit. The output terminal of the upper limit trigger circuit is connected to the first pin of the microprocessor unit, and the output terminal of the lower limit trigger circuit is connected to the second pin of the microprocessor unit.

9. The adjustable amplitude audio playback device according to claim 8, characterized in that, The differential signal attenuation circuit includes a fifth capacitor, a seventh capacitor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a third operational amplifier, and a sixth capacitor; The fifth capacitor is connected to the non-inverting input of the third operational amplifier through the twelfth resistor. The seventh capacitor is connected to the inverting input of the third operational amplifier through the thirteenth resistor. The output of the third operational amplifier is connected to the inverting input of the third operational amplifier through the fourteenth resistor. The output of the third operational amplifier is also connected to the first terminal of the sixth capacitor. The second terminal of the sixth capacitor is connected to the upper limit trigger circuit and the lower limit trigger circuit.

10. An adjustable amplitude audio playback device according to claim 9, characterized in that, The lower limit trigger circuit includes a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a second operational amplifier, a third diode, a fourth diode, and a fourth capacitor; The positive terminal of the third diode is connected to the second terminal of the sixth capacitor, and the negative terminal of the third diode is connected to the first terminal of the ninth resistor and the first terminal of the tenth resistor. The second terminal of the ninth resistor is connected to the inverting input terminal of the second operational amplifier. The second terminal of the ninth resistor is also grounded through the fourth capacitor. The second terminal of the tenth resistor is grounded. The positive terminal of the fourth diode is grounded, and the negative terminal of the fourth diode is connected to the second terminal of the sixth capacitor. The non-inverting input terminal of the second operational amplifier is grounded through the eighth resistor. The non-inverting input terminal of the second operational amplifier is also connected to the power supply through the sixth resistor. The output terminal of the second operational amplifier is connected to the power supply through the seventh resistor. The output terminal of the second operational amplifier is also connected to the second pin of the microprocessor unit.

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