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.
Transistor laser
The team credited with discovering the transistor laser was headed by Milton Feng and Nick Holonyak, Jr., and was based at the University of Illinois at Urbana-Champaign. Research into the transistor laser came about after Feng and Holonyak created the first light-emitting transistor in 2004. Feng and his team then modified the light-emitting transistor to focus the light it output into a laser beam. Their research was funded by DARPA. The paper written about the discovery of the transistor laser was ranked as a top five paper out of all of "Applied Physics Letters"’ history, and the transistor laser was called one of the top 100 discoveries by "Discover".