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HEWLETT 1 i PACKARD ' I 1 t SERVICE INFORMATION FROM HEWLETT-PACKARD 2nd Quarter 1988 Joe Corege Hew lett-Packard Volt (vdlt) n. Abbr. V 1. The Inter- national System unit of electric potential and electromotive force, equal to the difference of electric potential between two points on a conducting wire carrying a constant current of one ampere when the power dissipated between the points is one watt. 2. A unit of electric potential and electromotive force equal to 1.00034 times the Interna- tional System unit. In this sense, also called the "international volt." [After Count VOLTA.] Are you aware? The standard volt and the ohm will be correcting to a standard volt values. Hewlett-Pack- new legal value on 1 January 1990. ard is considering the impact this change will have in some applications There have been a few changes since of current and future HP products, the Treaty of the Meter was signed both hardware and software. Albuquerque, New Mexico. The arti- on 20 May 1875, (see Figure 1). cle is from the April/May 1988 issue The remainder of this article is re- of the Instrpmentation and Measure- The change in the Josephson Junction printed with permission from the ment Society newsletter and gives a frequency-voltage ratio 2 e / h is author, Dr. David W. Braudaway of history of changes since the- unit smaller in most countries compared Sandia National Laboratories in began in 1884. to the SI value set in 1972. Although the absolute value has not yet been determined, Figure 2 shows the ex- pected value each country must ad- President's Golurnn just. This table is from the "Report on the 17th Session of the Consulta- David W. Braudaway A brief review of the history of these tive Committee on Electricity" writ- Sandia National Laboratories values brings the perspective that ten in the Journal of Research of the A 1buq uerque, New Mexico this is not the first adjustment and National Bureau of Standards. that, as knowledge improves in the Comments and concerns continue to future, we should expect the need to In the U S . the volt is expected to be voiced on the change of the volt adjust again. change by approximately - 9 ppm, and ohm scheduled for 1 January France by -6.5 pmm and all other 1990. There is question as to why an A