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.
Jay Last
Fairchild's strategy for competing in the transistor market was to be fast and flexible. Rather than tying their research and development to lengthy 1-3 year military contracts, they financed development through Fairchild Camera. This enabled them to focus on promising ideas and develop them quickly. IBM was interested in obtaining transistors for a navigation computer for the B-70 bomber. Fairchild contracted to provide transistors to meet the specifications for IBM's core-memory driver. They developed complementary NPN and PNP transistors which could be used as a matched pair in a variety of circuit applications. Gordon Moore and David Allison worked on the NPN transistor, while Jean Hoerni developed the PNP transistor using boron diffusion. Scaling up to production of components in quantity presented major technological challenges, and Moore's NPN transistor was ready for production before Hoerni's PNP transistor. By August 1958, within 8 months of the company's creation, Fairchild was delivering Mesa transistors to IBM. Once it became available, the mesa transistor was desired for a wide variety of military applications. The speed with which it had been developed gave Fairchild a virtual monopoly on the fast-growing market for the next year. The most significant contract came from Autonetics, which was developing the navigation and control computer for the Minuteman ICBM.