Krótka historia przetworników elektroakustycznych w XIX wieku

One of the most important parts of the telephone are electro-acoustic converters, that is – microphones and earphones. At the beginning of the development of telephone, in the 19th century, when there were no amplifiers available for the technology, providing sufficient volume of voice transmission was not as easy as at the beginning of 20th century, when the vacuum tube was invented. The article is concerned with the part that was played in this process by Polish inventors, Henryk Machalski and Julian Ochorowicz.