Transistor
The transistor is the fundamental building block of modern electronic devices, and is ubiquitous in modern electronic systems. Julius Edgar Lilienfeld patented a field-effect transistor in 1926 but it was not possible to actually construct a working device at that time. The first practically implemented device was a point-contact transistor invented in 1947 by American physicists John Bardeen, Walter Brattain, and William Shockley. The transistor revolutionized the field of electronics, and paved the way for smaller and cheaper radios, calculators, and computers, among other things. The transistor is on the list of IEEE milestones in electronics, and Bardeen, Brattain, and Shockley shared the 1956 Nobel Prize in Physics for their achievement.
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).