Renard series

Renard series are a system of preferred numbers dividing an interval from 1 to 10 into 5, 10, 20, or 40 steps.[1] This set of preferred numbers was proposed ca. 1877 by French army engineer Colonel Charles Renard[2][3][4] and reportedly published in an 1886 instruction for balloon troops, thus receiving the current name in 1920s.[5] His system was adopted by the ISO in 1949[6] to form the ISO Recommendation R3, first published in 1953[7] or 1954, which evolved into the international standard ISO 3.[1] The factor between two consecutive numbers in a Renard series is approximately constant (before rounding), namely the 5th, 10th, 20th, or 40th root of 10 (approximately 1.58, 1.26, 1.12, and 1.06, respectively), which leads to a geometric sequence. This way, the maximum relative error is minimized if an arbitrary number is replaced by the nearest Renard number multiplied by the appropriate power of 10. One application of the Renard series of numbers is the current rating of electric fuses. Another common use is the voltage rating of capacitors (e.g. 100 V, 160 V, 250 V, 400 V, 630 V).

  1. ^ a b Cite error: The named reference ISO_3_1973 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Kienzle_1950 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Paulin_2007 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Sizes_2014 was invoked but never defined (see the help page).
  5. ^ Engineers, American Society of Mechanical (1924). Mechanical Engineering: The Journal of the American Society of Mechanical Engineers. American Society of Mechanical Engineers.
  6. ^ Cite error: The named reference ISO_17_1973 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference GOVPUB-C13_XNBSA was invoked but never defined (see the help page).