What kind of equipment does a microphone belong to in a microcomputer system?

In microcomputer systems, microphones are "input devices". Input devices are used to input commands, programs, data, text, graphics, images, audio and video information to the computer; microphones are energy conversion devices that convert sound signals into electrical signals, which can input audio information to the computer. So a microphone is an input device.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

In microcomputer systems, microphones are "input devices".

Input device: A device that inputs data and information to the computer. It is used to input commands, programs, data, text, graphics, images, audio and video and other information to the computer.

Keyboard, mouse, camera, scanner, light pen, handwriting input pad, joystick, Voice input device, etc. are all input devices. The voice input device includes a microphone.

Microphone, scientific name is microphone, translated from English microphone (microphone), also called microphone and microphone. A microphone is an energy conversion device that converts sound signals into electrical signals (The microphone can input audio information to the computer, so the microphone is an input device.).

Classification of microphones:

Microphones can be divided into two types: electric microphones and condenser microphones based on their energy conversion principles. Among them, the electric type can be subdivided into dynamic microphones and aluminum ribbon microphones.

Common commercial microphone types include condenser microphones, crystal microphones, carbon microphones and dynamic microphones.

There are two energy sources commonly used in condenser microphones: DC bias power supply and electret film.

Both condenser microphones and crystal microphones convert sound energy into electrical energy and produce a changing electric field. Carbon microphones use a DC voltage source to change their resistance through sound vibrations, thereby converting acoustic signals into electrical signals.

Condenser, crystal and carbon microphones all produce a voltage signal proportional to the displacement of the sensitive membrane, while dynamic microphones produce a voltage signal proportional to the vibration rate of the sensitive membrane.

The dynamic microphone uses permanent magnets as the energy source and converts sound energy into electrical energy based on the inductive effect.

Extended knowledge:

Most microphones are electret condenser microphones (ECM), a technology that has been around for decades. The ECM works by utilizing a diaphragm of polymeric material with permanent charge isolation. Compared with the polymer diaphragm of ECM, the performance of MEMS microphones is very stable at different temperatures and will not be affected by temperature, vibration, humidity and time. Due to its strong heat resistance, MEMS microphones can withstand high-temperature reflow soldering at 260°C without any change in performance. This can even save audio debugging costs during manufacturing due to minimal changes in sensitivity before and after assembly. At present, integrated circuit technology is being more and more widely used in the manufacturing of sensors and sensor interface integrated circuits. This micro-manufacturing process has the advantages of precision, flexible design, miniaturization, integration with signal processing circuits, low cost, and mass production. Early micromicrophones were based on the piezoresistive effect. There are research reports that a microphone with a (1×1)cm2, 2μm thick polysilicon film as a sensitive film was produced. However, in the absence of stress within the sensitive film, the first-order resonant frequency of such a large and thin polysilicon film will be lower than 300 Hz. The first-order resonant frequency in such a low frequency range will cause the frequency response of the microphone to be extremely uneven in the hearing frequency range (the change in sensitivity is greater than 40dB), which is unacceptable for microphone applications. When there is tensile stress in the sensitive film, its resonant frequency will increase at the expense of sensitivity. Of course, a higher first-order resonant frequency can be obtained by adjusting the size of the sensitive film, but this will still reduce the sensitivity. It can be seen that the piezoresistive solution is not suitable for the manufacture of micro microphones.

A feasible solution is to use a capacitive solution to create a miniature microphone. The advantage of this approach is that all materials used in the integrated circuit manufacturing process can be used for sensor manufacturing. However, it is quite difficult to manufacture micromicrophones using a single-chip process, because there can only be a small gap in the air medium between the two capacitor plates. Moreover, due to size limitations, the bias voltage is difficult to meet in some applications. Based on the above issues, research on condenser microphones has been ongoing

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