Miniature anti-interference waterproof microphone

Abstract

A PCBA (Printed Circuit Board Assembly) comprises an FET (Field Effect Transistor), the drain electrode of the FET is respectively connected with one end of a first resistor, one end of the first resistor is connected with a first capacitor, and the other end of the first capacitor is connected with the source electrode of the FET; the second capacitor is connected in parallel with the first capacitor and is externally arranged between the drain electrode and the source electrode; the other end of the third capacitor is a microphone signal input end, the other end of the third capacitor is connected with the second resistor, the other end of the second resistor is a microphone signal output end, the first capacitor and the first resistor form a high-pass filter, and the first capacitor and the first resistor and a parasitic capacitor of the FET field effect transistor jointly filter and filter power frequency interference signals; the first resistor and the second capacitor form an output signal low-pass filter to filter high-frequency and WIFI signal interference; and the second resistor and the third capacitor form a microphone peripheral test standard circuit, so that the voltage and the microphone work and are synchronously output.

Description

Technical Field

[0001] This utility model belongs to the field of microphone equipment technology, specifically relating to a small, anti-interference, waterproof microphone. Background Technology

[0002] With the development of technology, microphones are increasingly being used in security, smart home and IoT products. The frequency bands (2.4G, 4G, 5G, 5.6G) of these electronic products are becoming more and more widely used, and these electronic products are becoming smaller and smaller. Due to their size and structure, microphones also need to be made smaller. Common interferences include low-frequency power frequency interference and high-frequency electromagnetic and WIFI interference. Therefore, higher requirements are placed on their anti-interference capabilities. In addition, some products are used outdoors, which also leads to waterproofing. Utility Model Content

[0003] The purpose of this invention is to provide a small, anti-interference, waterproof microphone to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A small, anti-interference, waterproof microphone includes an external capacitor, a PCBA circuit board, a cavity, a copper ring, a back electrode plate, a gasket, a diaphragm, a housing, and a waterproof mesh. The PCBA circuit board is disposed inside the housing. The cavity, copper ring, gasket, and diaphragm are disposed along the side edge of the PCBA circuit board. The back electrode plate and waterproof mesh are disposed on both sides of the PCBA circuit board, respectively. A third external capacitor is disposed on the top of the PCBA circuit board.

[0006] The PCBA circuit board includes a FET field-effect transistor. The drain of the FET is connected to one end of a first resistor, one end of the first resistor is connected to a first capacitor, and the other end of the first capacitor is connected to the source of the FET, forming a circuit.

[0007] The second capacitor is connected in parallel with the first capacitor and is externally placed between the drain and the source.

[0008] The other end of the third capacitor is the microphone signal input terminal, and the other end is connected to the second resistor. The other end of the second capacitor, the other end of the first resistor, and the source of the FET are all grounded. The other end of the second resistor is the microphone signal output terminal, wherein:

[0009] The first capacitor and the first resistor form a high-pass filter, which, together with the parasitic capacitance of the FET field-effect transistor, filters out power frequency interference signals.

[0010] The first resistor and the second capacitor together form an output signal low-pass filter to filter out high-frequency and WIFI signal interference.

[0011] The second resistor and the third capacitor form the standard test circuit for the microphone's peripheral components, providing voltage and synchronous output for microphone operation.

[0012] Preferably, the first capacitor is 6.8nF to 10nF, the second capacitor is 1 to 33pF, the third capacitor is 0.1uF to 10uF, the first resistor is 300 to 470Ω, and the second resistor is 2000 to 3000Ω.

[0013] Preferably, the cutoff frequency of the high-pass filter is FH0 = 1 / (2*π*R1*C1) = 48-60Hz.

[0014] Preferably, the cutoff frequency of the low-pass filter is FH0 = 1 / (2*π*R1*C2) = 2.4G~5.6G.

[0015] Preferably, the waterproof mesh is bonded to the outer shell using waterproof sealant.

[0016] The technical effects and advantages of this utility model are as follows:

[0017] The DC power supply is provided to the microphone after decoupling via C3 and voltage division via R2. The vibration signal generated by the diaphragm is converted into an electrical signal by a FET, then filtered by a high-pass filter (C1 & R1) to remove power frequency interference; and then filtered by a low-pass filter (R1 & C2) to remove Wi-Fi signal interference, achieving a high anti-interference effect. This effectively filters out high-frequency noise and low-frequency interference, resulting in effective sound reception in Wi-Fi and Bluetooth products. The sound inlet is sealed with a high-density waterproof mesh and waterproof adhesive, achieving an IP67 waterproof rating. An external third capacitor is used as part of the microphone's external testing standard circuit. It can provide a variety of effects and functions. The signal shaping capacitor can form an RC circuit with the resistor for signal shaping, such as reducing spikes, ringing, or filtering out unwanted frequency components. The third capacitor helps improve electromagnetic compatibility and reduce electromagnetic interference. In addition, the external capacitor can provide power supply decoupling, stabilize the power supply voltage, and reduce the impact of power supply noise on the test results. The third capacitor can also be used to isolate DC components to ensure that the test signal is a pure AC signal and guarantee accuracy. The third capacitor is also used to protect the test circuit from the effects of accidental voltage surges or transient events. The third capacitor works in conjunction with the microphone's internal circuitry to suppress environmental noise and improve the signal-to-noise ratio. Attached Figure Description

[0018] Figure 1 This is the circuit schematic diagram for this embodiment;

[0019] Figure 2 This is a schematic diagram of the exploded structure of this embodiment.

[0020] In the diagram: 1. Waterproof mesh; 2. Outer shell; 3. Diaphragm; 4. Gasket; 5. Back electrode film; 6. Cavity; 7. Copper ring; 8. PCBA board; 9. Third capacitor. Detailed Implementation

[0021] The following will refer to the appendix in the embodiments of this utility model. Figures 1-2 The technical solutions in the embodiments of this utility model are clearly and completely described herein. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The specific embodiments described herein are merely used to explain this utility model and are not intended to limit this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] Example:

[0023] like Figures 1-2 As shown, this utility model provides a small anti-interference waterproof microphone, including an external capacitor, a PCBA circuit board, a cavity 6, a copper ring 7, a back electrode plate, a gasket 4, a diaphragm 3, a shell 2, and a waterproof mesh 1. The PCBA circuit board is housed inside the shell 2. The cavity 6, copper ring 7, gasket 4, and diaphragm 3 are arranged along the side edge of the PCBA circuit board. The back electrode plate and waterproof mesh 1 are respectively arranged on both sides of the PCBA circuit board. The waterproof mesh 1 is bonded to the shell 2 with waterproof sealant. A third external capacitor 9 is located on the top of the PCBA circuit board. Figure 1 (C3);

[0024] The PCBA circuit board includes FET field-effect transistors, and the drains of the FET field-effect transistors are connected to the first resistor ( Figure 1 One end of R1, one end of the first resistor, and one end of the first capacitor ( Figure 1 The first capacitor (C1) is connected to the first capacitor, and the other end of the first capacitor is connected to the source of the FET, forming a circuit;

[0025] Second capacitor ( Figure 1 C1) is connected in parallel with the first capacitor and is externally placed between the drain and the source.

[0026] The other end of the third capacitor 9 is the microphone signal input terminal, and the other end is connected to the second resistor ( Figure 1 Connect R2) to the ground. The other end of the second capacitor, the other end of the first resistor, and the source of the FET are all grounded. The other end of the second resistor is the microphone signal output terminal.

[0027] The first capacitor and the first resistor form a high-pass filter, which, together with the parasitic capacitance of the FET field-effect transistor, filters out power frequency interference signals.

[0028] The first resistor and the second capacitor together form a low-pass filter for the output signal, filtering out high-frequency and WIFI signal interference.

[0029] The second resistor and the third capacitor form the standard test circuit for the microphone's external components, providing voltage and synchronous output for microphone operation.

[0030] This utility model is a 4mm omnidirectional electret microphone with 360° sound pickup. The circuit composed of capacitors and resistors functions as follows:

[0031] The first capacitor has a value of 6.8nF to 10nF, the second capacitor has a value of 1 to 33pF, the third capacitor has a value of 0.1uF to 10uF, the first resistor has a value of 300 to 470Ω, and the second resistor has a value of 2000 to 3000Ω.

[0032] R1 and C1 form a high-frequency pass filter for frequency selection, and together with the parasitic capacitance of the FET, filter out power frequency interference signals. F0 = 1 / (2*π*R1*C1) = 48-60Hz.

[0033] FET: Amplifies vibration signals and converts them into electrical signals for output.

[0034] R1, C2: Resistor R2 and FET parasitic capacitance form a low-pass filter to filter out high-frequency and WIFI signal interference. F0 = 1 / (2*π*R1*C2) = 2.4G~5.6G.

[0035] R2 and C3 form the standard test circuit for the microphone's external components, providing voltage and power to the microphone. The signal output is decoupled through capacitor C3, and the power supply Vs is connected to the microphone's positive terminal through load resistor R2.

[0036] The standard operating voltage of this invention is DC 3V, and the operating current is Max: 0.5mA. The electrical signal generated by the microphone diaphragm 3 is filtered by high-pass filter C1 and R1 for frequency selection, and then filtered by the parasitic capacitance of the FET field-effect transistor to remove power frequency interference signals. After impedance matching with the FET via C2 and R1, high-frequency and WIFI signal interference is removed, achieving a high anti-interference shielding effect. It filters out high-frequency noise and low-frequency interference, and is effective in WIFI and Bluetooth products, providing clean sound with no noise. The sound inlet is sealed with a high-density waterproof mesh 1 and waterproof adhesive. The waterproof adhesive can be UV glue, black glue, silicone, etc., to achieve good waterproof performance, reaching IP67.

[0037] Finally, it should be noted that the above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A small, anti-interference, waterproof microphone, comprising an external capacitor, a PCBA circuit board, a cavity (6), a copper ring (7), a backplate, a gasket (4), a diaphragm (3), a shell (2), and a waterproof mesh (1), characterized in that: The PCBA circuit board is provided inside the outer shell (2). The PCBA circuit board has a cavity (6), a copper ring (7), a washer (4), and a diaphragm (3) along its side. The back electrode plate and a waterproof mesh (1) are provided on both sides of the PCBA circuit board. A third capacitor (9) is externally placed on the top of the PCBA circuit board. The PCBA circuit board includes a FET field-effect transistor. The drain of the FET is connected to one end of a first resistor, one end of the first resistor is connected to a first capacitor, and the other end of the first capacitor is connected to the source of the FET, forming a circuit. The second capacitor is connected in parallel with the first capacitor and is externally placed between the drain and the source. The other end of the third capacitor (9) is the microphone signal input terminal, and the other end is connected to the second resistor. The other end of the second capacitor, the other end of the first resistor, and the source of the FET are all grounded. The other end of the second resistor is the microphone signal output terminal, wherein: The first capacitor and the first resistor form a high-pass filter, which, together with the parasitic capacitance of the FET field-effect transistor, filters out power frequency interference signals. The first resistor and the second capacitor together form an output signal low-pass filter to filter out high-frequency and WIFI signal interference. The second resistor and the third capacitor (9) form the microphone peripheral test standard circuit, which provides voltage and microphone operation and outputs synchronously.

2. The small, anti-interference, waterproof microphone according to claim 1, characterized in that: The first capacitor has a value of 6.8nF to 10nF, the second capacitor has a value of 1 to 33pF, the third capacitor has a value of 0.1uF to 10uF, the first resistor has a value of 300 to 470Ω, and the second resistor has a value of 2000 to 3000Ω.

3. A small, anti-interference, waterproof microphone according to claim 2, characterized in that: The cutoff frequency of the high-pass filter is FH0 = 1 / (2*π*R1*C1) = 48~60Hz.

4. A small, anti-interference, waterproof microphone according to claim 2, characterized in that: The cutoff frequency of the low-pass filter is FH0 = 1 / (2*π*R1*C2) = 2.4~5.6G.

5. A small, anti-interference, waterproof microphone according to claim 1, characterized in that: The waterproof mesh (1) is bonded to the outer shell (2) with waterproof sealant.

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