Why should the receiver and receiver be connected in series in a circuit after the phone is connected?

Because the currents in series circuits are equal everywhere, the principle of telephone is to convert acoustic signals into electrical signals and then into acoustic signals. In order to hear the same sound from the microphone, a series connection is needed.

Telephone [English: telephone, from Greek τ? λε(tēle, meaning "far") and φ ω ν? (ph not n ē, meaning "sound"), the old translation is long-distance communication equipment, which can send and receive sound. As early as the eighteenth century, the word "telephone" was used in Europe to refer to a microphone strung together with wires (a cup strung together with wires) The telephone was attributed to Alexander Graham Bell. The principle of early telephone is that sound is a compound vibration in the air, which can be transmitted to solids and to conductive metals through electric pulses. Bell applied for the telephone patent in March 1876.

On June 5th, 2002, the United States Congress confirmed Antonio Muzzi as the inventor of the telephone. Zi Mu first showed his invention to the public on 1860, and published an introduction in an Italian newspaper in new york.

The improvements and inventions of telephone in history include: toner microphone, manual switchboard, dial, automatic telephone exchange, program-controlled telephone exchange, dual-tone multi-frequency dialing, voice digital sampling and so on. In recent years, new technologies include ISDN, DSL, VoIP, analog mobile phone and digital mobile phone.

This industry is usually divided into telephone equipment manufacturers and telephone network operators. Historically, network operators usually have a national monopoly position. In recent years, with the opening and integration of the global telecommunications market and the development of technology, there has gradually emerged a situation in which many operators compete in the same market. For example, Bell system, that is, AT & amp； T's subsidiary once owned 80% of the American telephone market. During the period of 1984, Bell system was forced to be divided into several independent local Bell companies due to the antitrust lawsuit of the US Department of Justice. There is a saying that can explain this phenomenon: At & amp； Before T was divided, IBM was the second largest company in America. at at & at； After T was divided into seven companies, IBM ranked eighth.