Bipolar ionizer circuit includes a high voltage AC voltage generator having a high potential output and a low potential output, the high potential output being capacitively coupled to respective high potential inputs of a pair of mutually opposite polarity voltage multipliers and the low potential output being capacitively coupled via an auxiliary capacitor to respective low potential inputs of the voltage multipliers. Outputs of the voltage multipliers are connected to respective ionizing electrodes, and an external ion imbalance indicator is connected in parallel to the auxiliary capacitor, which is thereby able to provide automatic balance of the ion current.