This century has seen electricity and electronics play an ever increasing role in business and private existence. For example, in the last 20 years there has been an enormous expansion of communication facilities and computer installations. Fundamental to the successful use of electricity is standardization of the basic electrical parameters (primarily the volt and the ampere) on a national and international basis and means to disseminate the standardization to electricity users. The fundamental electrical standards are maintained by the various governments, most of whom participate in programs of inter-comparison.
The 1970s
Rotek Instrument Corp. was organized in 1970 to provide the necessary link between users of electrical and electronic equipment and the fundamental electrical standards. This linkage has taken the form of precise, working sources of voltage and current, which are used worldwide as the working standards of government and industry. These sources are commonly called "calibrators" and are used primarily to test electrical meters.
Rotek's first calibrators were the Series 300 Precision Calibrators, multifunction devices suitable for testing voltmeters, volt-amp-ohm meters and digital multimeters. The 300 Series introduced simplicity and speed to the calibration process; simplicity by minimizing operator controls and making their functions self evident, and speed by virtue of a proprietary, fast responding circuit developed by Rotek and covered by US Patent 3,717,822. One of this Series, the Model 310, was the first remotely programmable, multifunction calibrator. This device became the manufacturing test standard for almost every major digital and analog multimeter manufacturer in the world.
During the 1970s, concern about the cost of energy stimulated activity in the measurement of electrical energy. The Rotek Series 800 Power and Energy Calibrators were the first comprehensive instruments for the testing and calibration of watt-meters and watt-hour meters. Introduced in 1976, the Series 800 Power and Energy Calibrators were unique in that their microprocessor circuits performed many computations to simplify the calibration process. The Series 800 replaced the complex interconnections and makeshift arrangements previously used for this purpose.
The 1980s
The 300 Series was replaced in 1980 by the 3900A Series, a broad family of calibrators, incorporating the features of the 300 Series, but offering in addition a diversity of performance capabilities to accommodate the differing needs and budgets of customers. The different models of this Series were designed to provide a high performance to price ratio.
The continuing development of electronic technology, particularly improvements in integrated circuits, placed new demands on voltage and current calibrators for greater accuracy and power. Economic considerations were also stimulating a demand for automatic operation. The 710 Calibration Standard was introduced to meet these requirements. The Model 710 extended performance in accuracy and power to limits unachievable by competitive equipment and had accuracies of 0.002% for dc voltage and 0.025% for ac voltages. The 710 also included the IEEE Interface, an interface for programmable instrumentation allowing it to conform to an industry-wide standard.