SIC 3825 Instruments for Measuring and Testing of Electricity and Electrical Signals
SIC 3825
This industry is made up of companies that manufacture a multitude of analytical devices. Examples of industry output include voltmeters, ammeters, wattmeters, watt-hour meters, semiconductor test equipment, and circuit testers. Establishments that produce monitoring and testing equipment for navigational, radar, and sonar systems are described in SIC 3812: Search, Detection, Navigation, Guidance, Aeronautical, and Nautical Systems and Instruments.
334416
Electronic Coil, Transformer, and Other Inductor Manufacturing
334515
Instrument Manufacturing for Measuring and Testing Electricity and Electrical Signals
After increasing in value almost every year during the 1990s, the economic recession of the early 2000s adversely affected the electrical testing and measuring industry. Total shipment values declined from a high of $16 billion in 2000 to $10 billion in 2003. Reflecting significant consolidation and relocation of jobs overseas, while shipment values more than doubled from 1987 to 2000, the number employees working in the industry declined by nearly half—from 95,800 in the mid-1980s to less than 48,000 by the mid-2000s. The industry, which is notoriously cyclical with sharp ups and downs, recovered during 2004, but a decline in the semiconductor sector during the first quarter of 2005 prompted some concerns that the industry may be once again entering a downswing.
Growth in the mid-1990s was due to demand for automatic test equipment (ATE), a devalued U.S. dollar, and shipments of high-tech devices to telecommunications industries. Despite increased foreign competition, the United States widened its trade surplus to $2.6 billion in 1996 and poised itself for steady global expansion into the 2000s. However, the bottom fell out of the telecommunications industry and the U.S. economy entered a recession during the early 2000s. At the same time, testing equipment was getting much more complicated and costly.
The electrical testing and measuring (T&M) instruments industry encompasses eight major product groups. ATE, the largest industry segment, includes T&M instruments for semiconductors, circuit boards, and computer disk drives. Communications test equipment, the second-ranked product group, includes T&M devices for landline, wireless, and fiber-optic communications gear.
Other major industry categories include signal generators, electrical integrating instruments, multimeters, oscilloscopes, and spectrum analyzers. Each of these product groups is comprised of many different devices. In addition, more than half of industry revenues are garnered from a wide range of miscellaneous T&M instruments, such as tube testers, impedance measurers, frequency meters, battery testers, stroboscopes, tachometers, reflectometers, ammeters, and ohmmeters.
Ohmmeters, a common and traditional product of the industry, are used to measure the amount of electrical resistance in a circuit. Likewise, watt-hour meters are most often used to measure the amount of power that is used by a utility customer and are mounted on an outside wall of most homes and buildings. Potentiometers are used to precisely measure direct current or voltage, as are voltmeters and ammeters. The galvanometer, another indicating instrument, indicates extremely small currents. Reflectometers measure the amount of light or energy reflected from a surface. An oscilloscope converts electron motion into a visual display on a cathode-ray tube.
In the mid-2000s, nearly one-third of the companies in the industry, representing over 35 percent of total sales, were located in California due to the large defense, semiconductor, and telecommunications industries in that state.
In 1833, Englishman Carl Friedrich Gauss was the first to show that magnetic quantities could be measured in terms of mechanical units. Wilhelm Weber, also of England, defined a system of electrical units in 1851 that foreshadowed the development of the ohm (1864), a measure of electrical resistance. The ampere, a unit used to measure electrical current, soon followed. The United States made the ohm and ampere legal units of electrical measurement in 1894.
Early measuring devices were functional, though generally unreliable for precise readings. The earliest device that would deliver a standard for voltage (electromotive force) for measuring instruments was built in 1836 and was reproducible only to about 1 percent accuracy. The Clark Cell of 1872, which was used to establish a standard voltage measurement, also proved unreliable. The Weston Cell, introduced in 1892, became the first device to successfully provide a standard for electrical measuring.
Following the development of electrical units and credible standards, numerous electricity measuring devices emerged during the early 1900s. Among the first devices were instruments used to measure electrical resistance, such as ohmmeters. In addition, power meters, or wattmeters, became industry mainstays. One of the largest classes of early devices was indicating instruments, such as voltmeters and ammeters.
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