  It is well known that additional ionization in the vicinity of a positively
biased electrode immersed into a weakly ionized plasma is responsible for a
hysteresis in the electrode current-voltage characteristics and the current
self-oscillations rise. Here we show both experimentally and theoretically that
under certain conditions these phenomena cannot be correctly interpreted once
considered separately from the reference electrode current-voltage
characteristics. It is shown that small electrodes can be separated into three
groups according to the relation between the electrode and the reference
electrode areas. Each group is characterized by its own dependence of the
collected current on the bias voltage.
