Transistor
From November 17, 1947, to December 23, 1947, John Bardeen and Walter Brattain at AT&T's Bell Labs in Murray Hill, New Jersey of the United States performed experiments and observed that when two gold point contacts were applied to a crystal of germanium, a signal was produced with the output power greater than the input. Solid State Physics Group leader William Shockley saw the potential in this, and over the next few months worked to greatly expand the knowledge of semiconductors. The term "transistor" was coined by John R. Pierce as a contraction of the term "transresistance". According to Lillian Hoddeson and Vicki Daitch, authors of a biography of John Bardeen, Shockley had proposed that Bell Labs' first patent for a transistor should be based on the field-effect and that he be named as the inventor. Having unearthed Lilienfeld’s patents that went into obscurity years earlier, lawyers at Bell Labs advised against Shockley's proposal because the idea of a field-effect transistor that used an electric field as a "grid" was not new. Instead, what Bardeen, Brattain, and Shockley invented in 1947 was the first point-contact transistor. In acknowledgement of this accomplishment, Shockley, Bardeen, and Brattain were jointly awarded the 1956 Nobel Prize in Physics "for their researches on semiconductors and their discovery of the transistor effect".
Les Hoffman
The invention of the transistor in 1948 must have had an effect on Leslie Hoffman. In the early 1950s, he took a major interest in solar cells, also called photovoltaic cells. When Bell Labs introduced the solar cell to the world in 1951 it was only a curiosity. It had a very poor light-to-electricity conversion efficiency of 2 percent, and was very fragile and expensive to fabricate. Several manufacturers, including Hoffman, managed to improve the efficiency to 4.5 percent by 1954, but photovoltaic cells were still impractical.
Hoffman made great strides in making the solar cell a practical and useful source of renewable energy. From 1957 to 1960, he improved its efficiency from 4.5 to 14 percent and lowered the production cost to make it a marketable item. One of Hoffman's great achievements was the first satellite to be powered by solar cells, the Vanguard 1, launched in 1958. The solar arrays or panels are Hoffman photovoltaic cells. In 1959 H. Leslie Hoffman received the David Packard Medal of Achievement for innovation. In 1959 he was one of the board of directors for the Electronic Industries Association (EIA).