Scientists have created a fundamentally new type of speaker from graphene
Virtually all existing today the speakers are working on the same principle: the electric signal produces fluctuations in the coil in field of permanent magnet that drives the cone, and this, in turn, generates air vibrations and the sound waves of the required frequency. But in the future things can change, because British scientists from Exeter University have created a fundamentally new type of dynamics of graphene, which does not need mechanical vibration.
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The principle of the new dynamics is based on the change of temperature, the graphene changes which result in sound. Previously, graphene is already used to create the speakers, but in the past it was made diffusers that increase the efficiency of the device. From the new dynamics disappeared all moving parts, which allowed to significantly reduce the size and increase efficiency. Speaker made in the form of a microprocessor the size of a thumb nail. Inside the processor, in addition to the dynamics, hidden amplifier and even the graphic equalizer.
Thermoacoustic principle of operation allows you to convert temperature into sound, or Vice versa — to convert sound vibrations into heat. This effect was first described in the late XIX century, scientists Lord Rayleigh. In the mid-twentieth century interest in the relationship of sound and heat is greatly increased, since it was necessary to study the instability in the combustion chamber with huge temperature changes. Today, there are thermoacoustic engines and thermoacoustic refrigerators even. But thermoacoustic speakers, and even from graphene, no one has yet created.
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Graphene is an excellent conductor, therefore, passing through it the electrical impulses, it is possible to quickly heat and cool it. Graphene membrane expands and contracts, which has an impact on the surrounding air and generates sound waves. How good are obtained in this way sound? A team of researchers argues that a graphene thermoacoustic speaker allows you to get "rich palette of sounds", depending on how and where it is electricity. Cycles of heating and cooling allow you to create numerous sound frequencies at the same time and mix them together, enhancing and tuning their sound. Scientists have even managed to get the ultrasound. published