The Johnsen-Rahbek Electrical Attraction and its Application

Abstract

Under direct current voltage supply, the writer deals with the adhesive force set up between a metal plate and a semi-conductor with which it is in close contact, and the resistance of such a system.
In the case of a plain semi-conductor, the adhesive force is only about the second power of the applied potential, in spite of the contact surfaces are polished with special attension.
The increase of the cond ctivity with increasing potential difference is chiefly due to the variation of the distribution of moisture at interface and the electrou emitted from the metal, and not coming into more intimate contact at higher potentials, unless the contact surfaces are polished carefully.
The difference of conductivity due to polarity is especially remarkable in agate.
As an application of this adhesive force, a simple telephone receiver and a transmitter have been contrived.
This paper includes the following topics:-
I. Introduction.
II. Volta e-pressure changes.
III. Current-pressure changes.
IV. Variation of resistance with time of application of potential difference.
V. Voltage-Resistance changes.
(a) in atomosphere
(b) in dry state only at contact surfaces.
VI. Application.
VII. Conclusion.