The date of birth of the first electric phone is February 14, 1876. On this day, the US Patent Office received two applications for an apparatus for transmitting sounds at a distance by means of an electric current. The first belonged to the American teacher of the deaf-mute school A.G. Bell. The second, which arrived two hours later, was the American physicist I. Gray. Both applications were not at all similar, but fundamentally different. Bell designed an electromagnetic transmitter (microphone) in which the current transferred to the line was changed due to a change in the magnetic flux. Gray, however, proposed a completely different method of changing the current, due to a change in the electrical resistance of the column of the conductive liquid when the membrane vibrates. Without dwelling on comparing the advantages and disadvantages of both devices, let us note the main thing. Bell patented an almost finished device. Gray only gave a preliminary notice of the intention to invent a device indicating the proposed principle of its operation.
But it would be unfair to attribute the laurels of the father of telephony only to A. Bell. His invention was preceded by the work of many scientists. The prototype of the telephone set, the so-called "nagging wire", was created in 1837 by the American scientist C. Paige. He discovered a phenomenon called galvanic music, an intermittent current flowing through the winding of the electromagnet and causing sounds of a certain tone.
In 1860, Philippe Reis (1834-1874), the physics teacher of the school in Friedrichsdorf (Germany), in the old school shed from improvised means (a cork from a barrel, a knitting needle, an old broken violin, a bundle of insulated wire and a galvanic cell) demonstrating the principle of the action of the ear. His apparatus consisted of a transmitter, a galvanic battery, a connecting wire and a receiver. Under the influence of sound waves, the transmitter's membrane came into oscillation, then immersed in mercury, then removing from it a platinum pin, connected by a linear wire with one end of the copper coil of the receiver coil. The other end is grounded. At the same time, an intermittent current was created in the circuit, under which the steel rod of the receiver was magnetized and demagnetized, which made it sound. His device, calling it "phone", he demonstrated on October 26, 1861, in front of members of the Physical Society of Frankfurt. In fact, it was a "music phone" transmitting sounds on wires, but these were only individual sounds with a distorted timbre. That is why Reus' electric telephone did not have any success. In the press appeared several semi-ironic and semi-serious articles, and the German magazine Gartenlaube gave in 1863 its description as a toy. The mechanic from Germany made in different design 10-20 phones Flight. Several of them even sold. One of the specimens found himself at the Scottish University in Edinburgh, at which time an American of English descent, Alexander Graham Bell, was studying.
In Germany, the flight was neither appreciated nor recognized. Then he went to America, where he was arrested as a charlatan, trying to extort money for a dubious venture - "to build an apparatus with the help of which it would be possible to transmit human speech by wires at any distance. He especially called his phone "phone", clearly imitating the name "telegraph", so that it would be easier to deceive people who heard about the successes of the telegraph apparatus but do not know the principle of its operation. Experts believe that you can not send a voice over the wires, as they pass the Morse code. However, if it was possible, it would not have any practical application, "the newspaper" Metropolitan "wrote.
Almost in parallel, in 1869, the professor of Kharkov University Yu. I. Morozov developed a transmitter, which is a vessel filled with a conductive liquid with two electrodes lowered into it. One of them was made in the form of a metal plate with a rigidly reinforced end. When it oscillated between it and the stationary electrode, the electrical resistance changed according to the sinusoidal law. Accordingly, the current in the circuit also changed. The transmitter of Morozov was a prototype of a microphone.
Back in the years of study, having familiarized himself with the flight's phone, Bell decided to create an apparatus that turns sounds into light signals. He hoped with his help to teach deaf children to speak. Beginning in 1873, he tried to design a harmonic telegraph capable of transmitting seven telegrams simultaneously (according to the number of notes in an octave). To do this, he used seven pairs of flexible metal plates, similar to a tuning fork, with each pair tuned to its frequency. During one of the experiments on June 2, 1875, the free end of one of the plates on the transmitting side of the line was welded to the contact. Assistant Bella mechanic Thomas Watson, unsuccessfully trying to fix the malfunction, swore. Located in another room and manipulating the receiving plates, Bell, with his sensitive, trained ear, caught the sound coming through the wire. Spontaneously fixed at both ends the plate turned into a kind of flexible membrane and, being above the pole of the magnet, changed its magnetic flux. As a result, the electric current flowing into the line changed according to the air vibrations caused by Watson's muttering. In practice, this was the time when the phone was born.
He filed a patent application for this phone on February 14, 1876, and received a patent on March 7. Three days later-March 10, 1876 - on the 12-meter wire that connected Ball's apartment with the laboratory in the attic, the first articulate phrase, which had become historical, was transmitted: "Mr. Watson, come here. I need you!". Despite the positive result, the invention for a long time did not find practical application. This is evidenced by the document presented in Annex 1.
True, being already famous and rich, Bell said: "I invented the phone due to my ignorance of electrical engineering. No one at least elementary in electrical engineering would have invented the phone. " The grain of truth in this statement is, since its apparatus was unusually simple, and if Bell followed all the laws of electrical engineering, the design should have been much more complicated ...
As mentioned above, the first permanent magnet phone, which is the prototype of the current one, was created in 1878 and was called the "Bell tube". In the cylindrical wooden case 1, there was a rod magnet 2 with a winding coil 3 at the end - near the metal membrane 6. The lead-out ends of the winding through the copper rods 4 were connected to the terminals of the telephone circuit 5. The horn 7 served for the concentration of air vibrations, both in speech transmission and her audition. When negotiating, Bell's tube had to be alternately applied to the mouth, then to the ear, or to use two tubes simultaneously. Therefore, in public places where the phone was installed, there was a warning: "Do not listen with your mouth, do not speak with your ear." Apparatus interested in the business community, which helped the inventor to establish "Bell Telephone Company." Subsequently, it turned into a powerful concern.
In 1878, DE Hughes reported to the Royal Society of London, of which he was a member, about the discovery of a microphone effect. Exploring bad electrical contacts, Hughes found that fluctuations in a bad contact are heard on the phone. Having tried the contacts made of various materials, he was convinced that the effect is most pronounced when using contacts from pressed coal. Based on these results, Hughes in 1877 designed a telephone transmitter, which he called a microphone. "Bella Company" used Hughes' new invention, since this part, which was absent in the first Bell apparatus, eliminated their main drawback - the limited range.
Many inventors worked on the improvement of the phone (V.Siemens, Ader, Gover, Shtaker, Dolbir, PM Golubitsky, etc.). The Russian scientist Mikhalsky in 1879 was the first in the world to apply coal powder in a microphone. This principle is used up to the present time. For the first time, by introducing an induction coil into the telephone circuitry and applying a carbon microphone from pressed lamp black, Edison ensured the transmission of sound over a considerable distance.