Large signal and transient characteristics of electrochemical amplifiers

Electrochemical cells in which the concentration of an ionic species in a chamber can be varied by means of an applied electrical signal constitute low-frequency analogs of the junction transistor. The analogy is pursued here by deriving equivalent circuits for such cells under large signal dc and transient conditions. In one sense the electrochemical cell may be regarded as a "perfect" semiconductor (no recombination of charge carriers). Therefore, parallels are noted to transistor equivalent circuits, particularly the charge control model, and equivalent switching-time equations are derived. Experimental data is compared to predicted results, and an electrochemical version of the Eccles-Jordan flip-flop is presented.