Calculator This led the way to the first credit-card-sized calculators, such as the Casio "Mini Card LC-78" of 1978, which could run for months of normal use on button cells. There were also improvements to the electronics inside the calculators. All of the logic functions of a calculator had been squeezed into the first "calculator on a chip" integrated circuits (ICs) in 1971, but this was leading edge technology of the time and yields were low and costs were high. Many calculators continued to use two or more ICs, especially the scientific and the programmable ones, into the late 1970s. The
Union Electric Company primarily in Missouri, where more than half of its customers reside in the St. Louis metropolitan area. It also serves adjoining parts of Illinois, and formerly served Iowa as well through the mid-1990s. Union Electric Company The Union Electric Company of Missouri (formerly ) was an electric power utility that was organized in 1902 and grew to be one of the S&P 500 largest companies in the United States. In 1997, its holding company merged with a smaller neighboring utility, Central Illinois Public Service Company through its holding company, CIPSCO Inc. (formerly ), to form Ameren Corporation () based in