Richardson Equation

an expression giving the magnitude of the saturation current density in thermionic emission. The equation was first obtained by O. W. Richardson on the basis of the classical electron theory of metals. Richardson subsequently refined the equation by a thermodynamic consideration of thermionic emission. The final modification in the equation was made by the American scientist S. Dushman on the basis of quantum theory. The equation obtained by Dushman is usually called the Richardson-Dushman equation.