Instruct: Given a question, retrieve passages that can help answer the question.
Query: When was the first microphone invented?
German inventor Johann Philipp Reis designed an early sound transmitter that used a metallic strip attached to a vibrating membrane that would produce intermittent current. Better results were achieved with the "liquid transmitter" design in Scottish-American Alexander Graham Bell's telephone of 1876 – the diaphragm was attached to a conductive rod in an acid solution. These systems, however, gave a very poor sound quality.
The first microphone that enabled proper voice telephony was the (loose-contact) carbon microphone. This was independently developed by David Edward Hughes in England and Emile Berliner and Thomas Edison in the US. Although Edison was awarded the first patent (after a long legal dispute) in mid-1877, Hughes had demonstrated his working device in front of many witnesses some years earlier, and most historians credit him with its invention. The carbon microphone is the direct prototype of today's microphones and was critical in the development of telephony, broadcasting and the recording industries. Thomas Edison refined the carbon microphone into his carbon-button transmitter of 1886. This microphone was employed at the first ever radio broadcast, a performance at the New York Metropolitan Opera House in 1910.
In 1916, E.C. Wente of Western Electric developed the next breakthrough with the first condenser microphone. In 1923, the first practical moving coil microphone was built. The Marconi-Sykes magnetophone, developed by Captain H. J. Round, became the standard for BBC studios in London. This was improved in 1930 by Alan Blumlein and Herbert Holman who released the HB1A and was the best standard of the day.
Thomas A. Edison invented the phonograph, the first device for recording and playing back sound, in 1877. After patenting the invention and benefiting from the publicity and acclaim it received, Edison and his laboratory turned their attention to the commercial development of electric lighting, playing no further role in the development of the phonograph for nearly a decade. Edison's original phonograph recorded on sheets of tinfoil and was little more than a crude curiosity, although one that fascinated much of the public. These earliest phonographs were sold mainly to entrepreneurs who made a living out of traveling around the country giving "educational" lectures in hired halls or otherwise demonstrating the device to audiences for a fee. The tinfoil phonograph was not fit for any real practical use and public interest soon waned.
Litke's wireless microphone was first tested at the Olympic trials held at Stanford University in 1959. Next, the American Broadcasting Company (ABC television) tested the microphone at the Democratic and Republican Conventions in 1960. Candidates John F. Kennedy and Richard Nixon were among the first celebrities to use the Vega-Mike. TV anchor John Daly praised Litke's invention on the ABC television news broadcast in July 1960. Daly introduced it to Americans with the words: "This is a Vega-Mike" and went on to explain it "is a wireless microphone, six inches long... without any wires of any kind..." Daly pointed out it could be used to broadcast "within the (convention) hall or outside... without the inconvenience of interconnecting microphone cables..." Even the Federal Communication Commission was impressed with it. The FCC gave him 12 frequencies instead of the one he was seeking.
The development of transistors in 1948 by Bell Laboratories led to major improvements to the hearing aid. The transistor was invented by John Bardeen, Walter Brattain, and William Shockley. Transistors were created to replace vacuum tubes; they were small, required less battery power and had less distortion and heat than their predecessor. These vacuum tubes were typically hot and fragile, so the transistor was the ideal replacement.The 1952 Sonotone 1010 used a transistor stage along with vacuum tubes, to extend battery life. The size of these transistors led to developments in miniature, carbon microphones. These microphones could be mounted on various items, even eyeglasses. In 1951, Raytheon manufactured the transistor and was one of the first companies to mass-produce transistors to throughout America. Raytheon realized that their hearing aid only lasted short-term and began to sell the vacuum-tube hearing aids again along with transistor hearing aids.
The development of thermionic valves starting around 1902, provided an entirely electronic method of amplifying signals. The first practical version of such devices was the Audion triode, invented in 1906 by Lee De Forest, which led to the first amplifiers around 1912. Since the only previous device which was widely used to strengthen a signal was the relay used in telegraph systems, the amplifying vacuum tube was first called an "electron relay". The terms "amplifier" and "amplification", derived from the Latin "amplificare", ("to enlarge or expand"), were first used for this new capability around 1915 when triodes became widespread.
An amplifier can either be a separate piece of equipment or an electrical circuit contained within another device. Amplification is fundamental to modern electronics, and amplifiers are widely used in almost all electronic equipment. Amplifiers can be categorized in different ways. One is by the frequency of the electronic signal being amplified. For example, audio amplifiers amplify signals in the audio (sound) range of less than 20 kHz, RF amplifiers amplify frequencies in the radio frequency range between 20 kHz and 300 GHz, and servo amplifiers and instrumentation amplifiers may work with very low frequencies down to direct current. Amplifiers can also be categorized by their physical placement in the signal chain; a preamplifier may precede other signal processing stages, for example. The first practical electrical device which could amplify was the triode vacuum tube, invented in 1906 by Lee De Forest, which led to the first amplifiers around 1912. Today most amplifiers use transistors.
The first telephone call was made on March 10, 1876 by Alexander Graham Bell. Bell demonstrated his ability to "talk with electricity" by transmitting a call to his assistant, Thomas Watson. The first words transmitted were "Mr Watson, come here. I want to see you." 
This event has been called Bell's "greatest success", as it demonstrated the first successful use of the telephone. Although it was his greatest success, he refused to have one in his own home because it was something he invented by mistake and saw it as a distraction from his main studies.
Porcelain was used in the first ceramic capacitors. In the early years of Marconi's wireless transmitting apparatus porcelain capacitors were used for high voltage and high frequency application in the transmitters. On the receiver side smaller mica capacitors were used for resonant circuits. Mica dielectric capacitors were invented in 1909 by William Dubilier. Prior to World War II, mica was the most common dielectric for capacitors in the United States.
Eventually communication reached an electronic state, and the telegraph was invented. Harrison Dyar, who sent electrical sparks through chemically treated paper tape to burn dots and dashes, invented the first telegraph in the USA. The telegraph was the first piece of equipment that allowed users to send electronic messages. A more developed version came from Samuel Morse, whose telegraph printed code on tape and was operated using a keypad and an earpiece. The pattern of communication soon became known as Morse code.
The first practical device that could amplify was the triode vacuum tube, invented in 1906 by Lee De Forest, which led to the first amplifiers around 1912. Vacuum tubes were used in almost all amplifiers until the 1960s–1970s when the transistor, invented in 1947, replaced them. Today, most amplifiers use transistors, but vacuum tubes continue to be used in some applications.
The development of audio communication technology in form of the telephone, first patented in 1876, created the need to increase the amplitude of electrical signals to extend the transmission of signals over increasingly long distances. In telegraphy, this problem had been solved with intermediate devices at stations that replenished the dissipated energy by operating a signal recorder and transmitter back-to-back, forming a relay, so that a local energy source at each intermediate station powered the next leg of transmission.
For duplex transmission, i.e. sending and receiving in both directions, bi-directional relay repeaters were developed starting with the work of C. F. Varley for telegraphic transmission. Duplex transmission was essential for telephony and the problem was not satisfactorily solved until 1904, when H. E. Shreeve of the American Telephone and Telegraph Company improved existing attempts at constructing a telephone repeater consisting of back-to-back carbon-granule transmitter and electrodynamic receiver pairs. The Shreeve repeater was first tested on a line between Boston and Amesbury, MA, and more refined devices remained in service for some time. After the turn of the century it was found that negative resistance mercury lamps could amplify, and were also tried in repeaters, with little success.
Swiss electrical engineer George de Mestral invented his first touch fastener when, in 1941, he went for a walk in the woods and wondered why Burdock seeds clung to his coat and dog. He discovered it could be turned into something useful. He patented it in 1955 and subsequently refined and developed its practical manufacture until its commercial introduction in the late 1950s.
Lee de Forest (August 26, 1873 – June 30, 1961) was an American inventor, self-described "Father of Radio", and a pioneer in the development of sound-on-film recording used for motion pictures. He had over 180 patents, but also a tumultuous career—he boasted that he made, then lost, four fortunes. He was also involved in several major patent lawsuits, spent a substantial part of his income on legal bills, and was even tried (and acquitted) for mail fraud. His most famous invention, in 1906, was the three-element "Audion" (triode) vacuum tube, the first practical amplification device. Although De Forest had only a limited understanding of how it worked, it was the foundation of the field of electronics, making possible radio broadcasting, long distance telephone lines, and talking motion pictures, among countless other applications.
Musical glasses were documented in Persia in the 14th century. The glass harp was created in 1741 by Irishman Richard Pockrich, who is known as the first virtuoso of the musical glasses. Pockrich called his instrument the "angelic organ" and it was played with sticks, rather than by rubbing the glasses with a moistened finger. It was reported in 1760 that, "Pockrich played Handel's "Water Music" on the glasses." His successful concert career was brought to a premature end by a fire in which both the inventor and instrument perished in 1759.
The development of the cavity magnetron in the UK made possible the production of electromagnetic waves of a small enough wavelength (microwaves). American engineer Percy Spencer is generally credited with inventing the modern microwave oven after World War II from radar technology developed during the war. Named the "Radarange", it was first sold in 1946. Raytheon later licensed its patents for a home-use microwave oven that was first introduced by Tappan in 1955, but these units were still too large and expensive for general home use. Sharp Corporation introduced the first microwave oven with a turntable between 1964 and 1966. The countertop microwave oven was first introduced in 1967 by the Amana Corporation. After Sharp introduced low-cost microwave ovens affordable for residential use in the late 1970s, their use spread into commercial and residential kitchens around the world. In addition to their use in cooking food, types of microwave ovens are used for heating in many industrial processes.
The first person to use resonant circuits in a radio application was Nikola Tesla, who invented the resonant transformer in 1891. At a March 1893 St. Louis lecture he had demonstrated a wireless system that, although it was intended for wireless power transmission, had many of the elements of later radio communication systems. A grounded capacitance-loaded spark-excited resonant transformer (his "Tesla coil") attached to an elevated wire monopole antenna transmitted radio waves, which were received across the room by a similar wire antenna attached to a receiver consisting of a second grounded resonant transformer tuned to the transmitter's frequency, which lighted a Geissler tube. This system, patented by Tesla 2 September 1897, 4 months after Lodge's "syntonic" patent, was in effect an inductively coupled radio transmitter and receiver, the first use of the "four circuit" system claimed by Marconi in his 1900 patent "(below)". However, Tesla was mainly interested in wireless power and never developed a practical radio "communication" system.
The development of radar, mainly in secrecy, before and during World War 2, resulted in the technological advances which made microwaves practical. Radar antennas small enough to fit on aircraft which had a narrow enough beamwidth to localize enemy aircraft required wavelengths in the centimeter range. It was found that conventional transmission lines used to carry radio waves had excessive power losses at microwave frequencies, and George Southworth at Bell Labs and Wilmer Barrow at MIT independently invented waveguide in 1936. Barrow invented the horn antenna in 1938 as a means to efficiently radiate microwaves into or out of a waveguide. In a microwave receiver, a nonlinear component was needed that would act as a detector and mixer at these frequencies, as vacuum tubes had too much capacitance. To fill this need researchers resurrected an obsolete technology, the point contact crystal detector (cat whisker detector) which was used as a demodulator in crystal radios around the turn of the century before vacuum tube receivers. The low capacitance of semiconductor junctions allowed them to function at microwave frequencies. The first modern silicon and germanium diodes were developed as microwave detectors in the 1930s, and the principles of semiconductor physics learned during their development led to semiconductor electronics after the war.
In 1947, Clarence and Ruby Moore began by modifying existing makes and models of tape recorders to make them more rugged. In 1949, Moore obtained a groundbreaking patent, the first tape recorder with a built-in power amplifier for public address duties, which was introduced in 1950. In 1953, Crown added a line of compact loudspeakers as accessories to the reel to reel tape recorders.
In 1959, Crown began making standalone tube power amplifiers. By 1963, solid state electronics development allowed Crown to produce a more robust tape recorder, and in 1964, their first solid state power amplifier: the low-profile SA 20-20. In 1967, the DC300 was introduced as the first AB+B circuitry amplifier with 150 watts per channel at eight ohms. The DC300 proved very popular with sound reinforcement system owners and moved Crown into a leadership position in terms of power amplifier sales worldwide. As well, the DC300 was seen as a breakthrough product by commercial sound system contractors seeking to power their constant voltage speaker systems without the frequency response limitations and power losses associated with output power transformers which had previously been required. In November 2007, after 40 years of service, the Crown DC300 was inducted into the TEC Awards TECnology Hall of Fame in New York on the opening day of the Audio Engineering Society's 123rd convention. George Peterson, executive editor of Mix magazine, said of the DC300 that it "was a classic that really ushered in and defined the era of the modern power amplifier."
In 1789, Franz Aepinus developed a device with the properties of a "condenser" (now known as a capacitor.) The Aepinus condenser was the first capacitor developed after the Leyden jar, and was used to demonstrate conduction and induction. The device was constructed so that the space between two plates could be adjusted, and the glass dielectric separating the two plates could be removed or replaced with other materials.
The first carburetor was invented by Samuel Morey in 1826. The first person to patent a carburetor for use in a petroleum engine was Siegfried Marcus with his 6 July 1872 patent for a device which mixes fuel with air.
Before the devices existed that are now referred to as mobile phones or cell phones, there were some precursors. In 1908, a Professor Albert Jahnke and the Oakland Transcontinental Aerial Telephone and Power Company claimed to have developed a wireless telephone. They were accused of fraud and the charge was then dropped, but they do not seem to have proceeded with production. Beginning in 1918, the German railroad system tested wireless telephony on military trains between Berlin and Zossen. In 1924, public trials started with telephone connection on trains between Berlin and Hamburg. In 1925, the company was founded to supply train telephony equipment and, in 1926, telephone service in trains of the Deutsche Reichsbahn and the German mail service on the route between Hamburg and Berlin was approved and offered to first-class travelers.
A mobile phone, or cell phone, is a long-range, electronic device used for mobile voice or data communication over a network of specialized base stations known as cell sites. Early mobile FM radio telephones were in use for many years, but since the number of radio frequencies were very limited in any area, the number of phone calls were also very limited. To solve this problem, there could be many small areas called cells which share the same frequencies. When users moved from one area to another while calling, the call would have to be switched over automatically without losing the call. In this system, a small number of radio frequencies could accommodate a huge number of calls. The first mobile call was made from a car phone in St. Louis, Missouri on June 17, 1946, but the system was impractical from what is considered a portable handset today. The equipment weighed 80 lbs, and the AT&T service, basically a massive party line, cost $30 per month plus 30 to 40 cents per local call. The basic network and supporting infrastructure of hexagonal cells used to support a mobile telephony system while remaining on the same channel were devised by Douglas H. Ring and W. Rae Young at AT&T Bell Labs in 1947. Finally in 1973, Martin Cooper invented the first handheld cellular/mobile phone. His first mobile phone call was made to Joel S. Engel in April 1973.
An electret microphone is a type of condenser microphone, which eliminates the need for a power supply by using a permanently charged material. Electret materials have been known since the 1920s, and were proposed as condenser microphone elements several times, but were considered impractical until the foil electret type was invented at Bell Laboratories in 1962 by Jim West, using a thin metallized Teflon foil. This became the most common type, used in many applications from high-quality recording and lavalier use to built-in microphones in small sound recording devices and telephones.
The first recorded patent for a wireless microphone was filed by Raymond A. Litke, an American electrical engineer with Educational Media Resources and San Jose State College, who invented a wireless microphone in 1957 to meet the multimedia needs for television, radio, and classroom instruction. His U.S. patent number 3134074 was granted in May 1964. Two microphone types were made available for purchase in 1959: hand-held and lavalier. The main transmitter module was a cigar-sized device which weighed . Vega Electronics Corporation manufactured the design in 1959, producing it as a product called the Vega-Mike. The device was first used by the broadcast media at the 1960 Democratic and Republican National Conventions. It allowed television reporters to roam the floor of the convention to interview participants, including presidential candidates John F. Kennedy and Richard Nixon.
Another German equipment manufacturer, Beyerdynamic, claims that the first wireless microphone was invented by Hung C. Lin. Called the "transistophone," it went into production in 1962. The first time that a wireless microphone was used to record sound during filming of a motion picture was allegedly on Rex Harrison in the 1964 film "My Fair Lady", through the efforts of Academy Award-winning Hollywood sound engineer George Groves.
Litke invented a wireless microphone in 1957 while employed as an electronics expert at San Jose State College. His supervisor challenged him to invent a microphone to use in educational presentations which would be free of wires.