Keithley Instruments, Inc. · Solon, OH United States ·(NYSE: KEI)

A wailing guitar? For the Rolling Stones, that's Keith's lead instrument. The company, Keithley Instruments, is more familiar to engineers, scientists, and technicians than to geezer rockers or their fans. Keithley makes some 500 different products, tools used to control, measure, and trace signals, whether they take the form of electrical current, light, or radio waves. Its portfolio includes digital multimeters, semiconductor parametric test and device characterization systems, signal analyzers and generators, and plug-in boards that enable PCs to be used for data acquisition. About three-quarters of Keithley's sales are to customers located outside the US. To read the full description, subscribe now.