A voltage driven corona current sensing probe, utilized to sense electrostatic charge (such as on aircraft), is provided with higher positive operating voltage than negative operating voltage to compensate for the different electron emission threshold and mobility of electrons compared to positive ions. In an AC embodiment, the voltage difference is achieved by a polarity-asymmetric voltage divider on a high voltage AC source feeding a single probe. In another embodiment, separate DC power supplies drive respective probes with different voltages.
