Many of the most important inventions of mankind, created to transmit sound over a distance, whether it be a radio or a telephone, could not do without a device for receiving sound waves. The invention of the microphone was so necessary that it was invented simultaneously in different parts of the planet. And it is still not completely clear which of the scientists can be called the ancestor of the device. Today, devices are used in almost all areas of life, ranging from complex space explorations to the conversation of nothing about two housewives on the phone. At the same time, few people think about how this seemingly simple device looks from the inside.
The principle of the microphone
The microphone's task is to convert sound waves into electrical impulses. They are recorded on media, and after that, thanks to special programs, they are again converted into sound, making it possible to listen to the recorded. To make sound recording possible, various types of microphones are used. The simplest of them work on the principle of a tympanic membrane. Air vibrations created by sound cause vibration of a thin film mounted inside the device. This diaphragm, in turn, moves an induction coil wound around a permanent magnet, that is, located in a constant magnetic field.
Due to this movement, electrical impulses appear in the coil, which go through wires to a sound recorder. The length and intensity of the pulse directly depends on the volume and time of exposure of the sound waves to the membrane.
Attention! There are much more complex types of such devices for which microchips and additional power sources are used. The sound quality obtained using more advanced technologies is many times higher than the capabilities of simple dynamic microphones.
Microphone design
The most widely used and widely used, work as follows:
- Classic (dynamic). It is by far the most affordable and, at the same time, the simplest in design. Using a very thin (several microns) tightly stretched paper membrane, it transmits sound vibrations to a coil located in a magnetic field. Due to the simplicity of their device, such devices are the most affordable. However, the signal transmission quality is rather poor.
- Capacitor. This is a more advanced sound pickup design. It is based on a capacitor, one of the plates of which plays the role of a diaphragm, receiving sound waves. Due to the oscillation of the plate, the capacitance of the capacitor changes, creating pulsed currents. For this kind of work, you need an additional power source, such as a battery, battery or cord for connecting to the network. This type of device is used for professional recording in studios.
- Electret. They are one of the varieties of capacitor devices, for their functioning a special electret composition is applied to the membrane, which creates the necessary voltage. Such a composition is able to work for more than 30 years. And the structure allows you to make it very miniature and use them in all kinds of gadgets - smartphones, tablets, laptops, smart watches.
What are the microphones
In addition to the most common dynamic and condenser microphones, there are other types.
Due to the complexity of the design, the high cost of production or insufficient quality indicators, they are less common. These include coal (Microphone Hughes), optoacoustic, piezoelectric and others, mainly used in very narrowly focused scientific experiments.
A beautiful melody that sounds in the player, the voice of a loved one who is not nearby - all this would have been impossible without a small assistant who knows how to create a stream of electrons in the wires from the sound.
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