众所周知,电话机中的换能器主要是送话器、受话器和振铃。碳粒送话器在电话机中的应用经历了一百多年。随着科学技术的发展,电话机的其他器件正以较快的速度由机电式向电子化过渡。与之相比,电话机中的换能器是发展较慢的,尤其是其中的送话器仍以碳粒式为主。 It is well-known that the transducers in telephones are mainly microphones, receivers and ringing. Carbon microphones have been used in telephones for over a hundred years. With the development of science and technology, other devices of the telephone are being rapidly electromechanically and electronically transitioned. In contrast, transducers in telephones are slow to develop, especially the microphones in which the microphones still dominate.