Comparison of Simon's and Van de Graaff's Theories of the Electrostatic Generator

The essential differences between the Van de Graaff's and Simon's theories of the electrostatic generator have been pointed out. According to Van de Graaff's theory: (i) The sphere acts as a Faraday's ice-pail; (ii) the rise of voltage is linear with time; (iii) the voltage attainable in the generator is equal to the breakdown potential of the sphere if there is no leakage of charge through the insulating support, etc.; and (iv) the voltage is a constant independent of the spraying voltage. According to Simon's theory: (i) The basic principle is the Volta's condensing electroscope principle; (ii) the rise of voltage is exponential with time; (iii) the attainable voltage is proportional to the spraying voltage; and (iv) the constant of proportionality does not depend on the capacity of the sphere, but depends on the positions of the spraying point, collecting point, and the sphere. The experiments performed with our generator show that the results are qualitatively in accordance with the Simon theory.