Most modern speakers use a vibrating membrane that converts electrical vibrations into vibrations in the air. But now researchers at the University of Exeter have developed a graphene-based speaker that doesn't need to vibrate. Sound is generated by heating graphene.
The speakers made by British scientists are completely free of moving parts, resulting in a minimized device, increasing its efficiency and economy. Suffice it to say that the speaker is about the size of a thumbnail.
The work of the speaker is based on the thermoacoustic principle, which was discovered by Lord Ralleigh at the end of the 19th century. Later, already in our time, thermoacoustic engines and refrigerators were created, now this "line" has been replenished with graphene-based speakers.
Being an excellent conductor, graphene, passing special current pulses through itself, is able to quickly heat up and cool down, which affects the air around the membrane. The resulting temperature fluctuations, alternately expanding and contracting the air, generate sound waves.
This gave them the ability to create a "rich sonic palette" by controlling the electrical current flowing through the graphene, the researchers note.