statfarad

Statfarad is the unit of electrical capacitance in the CGS electrostatic (Gaussian) system of units, part of the centimeter-gram-second (CGS) electrostatic (ESU) family. In this system, capacitance is defined as C = Q / V, where Q is charged in statcoulombs and V in statvolts, so one statfarad is the capacitance that stores one statcoulomb of charge at one statvolt: 1 statfarad = 1 statcoulomb per statvolt.

In the CGS-ESU framework, fundamental constants are embedded in the unit definitions, and Coulomb’s law takes the form F = q1 q2 / r^2 with r measured in centimeters and F in dynes. Energies are measured in ergs, with energy U = qV in these units. The CGS-ESU system is largely historical and was commonly used before the SI units became standard.

Conversions to SI units are well established: 1 statcoulomb ≈ 3.33564 × 10^-10 coulombs, 1 statvolt ≈ 299.792458 volts, and 1 statfarad ≈ 1.11265 × 10^-12 farads. Consequently, 1 statfarad is about 1.11 picofarads in SI terms.

Today, the statfarad is rarely used outside of historical discussions or specific theoretical treatments; modern measurements and engineering rely on SI units. Nonetheless, understanding statfarads helps in interpreting older literature and in appreciating how CGS units relate to contemporary metrology.