Daraf

Physical unit
Unit name	Daraf
Unit symbol	${\displaystyle \mathrm {daraf} }$
Physical quantity (s)	Elasticity
Formula symbol	${\displaystyle S}$
dimension	${\displaystyle {\mathsf {M\;L^{2}\;T^{-4}\;I^{-2}}}}$
In SI units	${\displaystyle \mathrm {1\,F^{-1}=1\;{\frac {kg\cdot m^{2}}{A^{2}\cdot s^{4}}}} }$
Named after	Farad (written backwards)
Derived from	farad

The Daraf ( farad written backwards) is a name introduced by Arthur Edwin Kennelly in 1936, common in the USA for the SI unit of the elastance, called the reciprocal value of the electrical capacitance , the inverse farad ( unit symbol F ⁻¹ ):

${\displaystyle 1\,\mathrm {F^{-1}} =1\,\mathrm {\frac {1}{F}} =1\,\mathrm {\frac {V}{C}} =1\,\mathrm {\frac {V}{A\cdot s}} =1\,\mathrm {\frac {kg\cdot m^{2}}{A^{2}\cdot s^{4}}} }$

The name, "Farad" written backwards, is not recognized in the International System of Units (SI).

swell

• Journal of the Institute of Electrical Engineers , (GB) Issue 78, page 241, 1936.