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.
Ralph Bown
Bown's work focused on electromagnetic propagation, particularly for radio broadcasting, ship-to-shore communication, aircraft radios, and intercontinental telephony. He was also an expert in radar, and served as a division member and consultant of the National Defense Research Committee and expert consultant to the Secretary of War; in 1941 he visited England to study radar in combat operations. Bown became research director at Bell Labs, and on June 30, 1948, led a press conference announcing the invention of the transistor.