Solion tetrode-a reliable integrator and memory device

The solion tetrode is an electrochemical cell whose output current is proportional to the integral of the input current. The principle of operation is based on the controlled flow of ions, specifically iodine, through the electrolyte. If a current is introduced into the input of the solion, the unit continuously reads out electrically the integral of the input current. When the input current is removed, the readout still holds the new and final value for several days with extremely low drift. This paper describes the development of a solion tetrode with the maximum emphasis on reliability (questionable long-term stability had been a primary roadblock to the widespread use of solions), and presents long term aging data. The effect of materials and construction techniques on the operating parameters of this solion tetrode are also discussed.