A model for the redox regulation of the functional state of the cell has been constructed on the basis of representation of electron transfer processes by equivalent electric circuits. The mechanism of action of redox active molecules on biosystems has been discussed in terms of circuit theory. A method for determining the parameters of cellular redox sensors has been proposed. It has been established that the concentration and redox potential of compounds entering the cell are the main regulatory parameters of redox signals for the cell. It has been experimentally shown that the calcium response to hydrogen peroxide in rat C6 glioma cells and human FL amnion cells depends on the redox buffer capacity of cells.