History of hearing aids
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.
History of science and technology in Japan
The parametron was a logic circuit element invented by Eiichi Goto in 1954. It was a digital computer element. Parametrons were used in Japanese computers from 1954 to the early 1960s, such as the University of Tokyo's PC-1 built in 1958, due to being reliable and inexpensive, but were ultimately surpassed by transistors due to differences in speed.The ETL Mark I, Japan's first digital automatic computer, began development in 1951 and was completed in 1952. It was developed by the Electrotechnical Laboratory using relays, based on the switching circuit theory formulated by Akira Nakashima in the 1930s and advanced by Goto Mochinori in the 1940s.The ETL Mark III began development in 1954, and was completed in 1956, created by Japan's Electrotechnical Laboratory. It was the first stored-program transistor computer. It used ultrasonic delay line memory.