Electret microphone with band-pass filter

Abstract

The electret microphone comprises a field effect transistor (FET), the G pole of the FET is connected with one end of the microphone, the other end of the microphone is grounded, the S pole of the FET is connected with a low-pass filtering module, and the low-pass filtering module is connected with a load resistor and a high-pass filtering module which are arranged in parallel. The microphone has the advantages that the band-pass filter is arranged inside, interference of low-frequency and high-frequency signals on the microphone is reduced through the band-pass filter, low-frequency vibration and electric signal interference are effectively eliminated, and the built-in load resistor is small in size and occupies less space.

Description

Technical Field

[0001] The utility model discloses an electret microphone with a bandpass filter, belonging to the technical field of electronics. Background Art

[0002] An electret microphone is a microphone commonly used in audio equipment. It can convert sound waves into electrical signals. An electret microphone usually includes: a metal shell, and metal pads, an electret structure, a plastic bracket, a metal back electrode and a field effect transistor arranged in sequence in the metal shell.

[0003] In the prior art, electret microphones are easily interfered by low-frequency and high-frequency signals during use. Microphones often have problems such as movement or friction during use, which will generate low-frequency vibrations and interference, causing instability in the microphone signal. In addition, electret microphones on the market require external load resistors to work properly, causing design problems for non-professional users. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide an electret microphone with a bandpass filter in view of the above shortcomings. The bandpass filter is built in to reduce the interference of low-frequency and high-frequency signals on the microphone, effectively eliminate low-frequency vibration and electrical signal interference, and the built-in load resistor is small in size and occupies less space.

[0005] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0006] An electret microphone with a bandpass filter comprises a field effect tube FET, wherein the G pole of the field effect tube FET is connected to one end of the microphone, the other end of the microphone is grounded, the S pole of the field effect tube FET is connected to a low-pass filter module, and the low-pass filter module is connected to a load resistor and a high-pass filter module arranged in parallel.

[0007] Furthermore, the D-pole of the field effect transistor FET is connected to one end of a capacitor C1 and to a VCC power supply, and the other end of the capacitor C1 is grounded.

[0008] Furthermore, the low-pass filter module includes a resistor R1, a capacitor C2 and a capacitor C3, one end of the resistor R1 is connected to one end of the capacitor C2 and the S pole of the field effect transistor FET, the other end of the capacitor C2 is grounded, the other end of the resistor R1 is connected to one end of the capacitor C3, and the other end of the capacitor C3 is grounded.

[0009] Furthermore, the other end of the resistor R1 is also connected to one end of a load resistor R2, and the other end of the load resistor R2 is grounded.

[0010] Furthermore, the high-pass filter module includes a capacitor C4, one end of which is connected to the other end of the resistor R1, the other end of which is connected to one end of the resistor R3 and connected to the client's device as an output end, and the other end of the resistor R3 is grounded.

[0011] The utility model adopts the above technical solution, and compared with the prior art, has the following technical effects:

[0012] The microphone of the utility model has a built-in bandpass filter, which reduces the interference of low-frequency and high-frequency signals on the microphone, effectively eliminates low-frequency vibration and electrical signal interference, and the built-in load resistor has a small volume and occupies less space. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the specific implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the specific implementation or the prior art description. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0014] Figure 1 This is a circuit diagram of the electret microphone in the utility model. DETAILED DESCRIPTION

[0015] Embodiment 1, as Figure 1 As shown, an electret microphone with a bandpass filter includes a field effect tube FET, wherein the G pole of the field effect tube FET is connected to one end of the microphone, and the other end of the microphone is grounded, the D pole of the field effect tube FET is connected to one end of the capacitor C1 and connected to the VCC power supply, the other end of the capacitor C1 is grounded, the S pole of the field effect tube FET is connected to a low-pass filter module, the low-pass filter module includes a resistor R1, a capacitor C2 and a capacitor C3, one end of the resistor R1 is connected to one end of the capacitor C2 and the S pole of the field effect tube FET, the other end of the capacitor C2 is grounded, the other end of the resistor R1 is connected to one end of the capacitor C3, one end of the load resistor R2 and the high-pass filter module, the other end of the capacitor C3 is grounded, the other end of the load resistor R2 is grounded, the high-pass filter module includes a capacitor C4, one end of the capacitor C4 is connected to the other end of the resistor R1, the other end of the capacitor C4 is connected to one end of the resistor R3, and is connected to the client's device as an output end, and the other end of the resistor R3 is grounded.

[0016] The field effect transistor FET is the impedance converter of the microphone signal output, and the output signal has a certain load capacity; capacitor C1 is the high-frequency filter capacitor at the power supply end, which is used to absorb the high-frequency interference signal at the power supply end; capacitor C2, capacitor C3 and resistor R1 form a low-pass filter, which is used to absorb high-frequency interference signals from the outside world; resistor R2 is a load resistor, which provides a power supply circuit for the FET core; capacitor C4 and resistor R3 form a high-pass filter, which is used to absorb friction, low-frequency vibration and low-frequency electrical signal interference.

[0017] The description of the present invention is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the present invention to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. An electret microphone with a bandpass filter, characterized in that: It includes a field effect tube FET, the G pole of the field effect tube FET is connected to one end of the microphone, the other end of the microphone is grounded, the S pole of the field effect tube FET is connected to a low-pass filter module, and the low-pass filter module is connected to a load resistor and a high-pass filter module arranged in parallel.

2. An electret microphone with a bandpass filter as claimed in claim 1, characterized in that: The D-pole of the field effect transistor FET is connected to one end of the capacitor C1 and to the VCC power supply, and the other end of the capacitor C1 is grounded.

3. An electret microphone with a bandpass filter as claimed in claim 1, characterized in that: The low-pass filter module includes a resistor R1, a capacitor C2 and a capacitor C3, one end of the resistor R1 is connected to one end of the capacitor C2 and the S pole of the field effect transistor FET, the other end of the capacitor C2 is grounded, the other end of the resistor R1 is connected to one end of the capacitor C3, and the other end of the capacitor C3 is grounded.

4. An electret microphone with a bandpass filter as claimed in claim 3, characterized in that: The other end of the resistor R1 is also connected to one end of a load resistor R2, and the other end of the load resistor R2 is grounded.

5. The electret microphone with a bandpass filter as claimed in claim 3, characterized in that: The high-pass filter module includes a capacitor C4, one end of which is connected to the other end of the resistor R1, the other end of which is connected to one end of the resistor R3 and connected to the client's device as an output end, and the other end of the resistor R3 is grounded.

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