A conducted electrical weapon ("CEW") launches wire-tethered electrodes to provide a current through a human or animal target to impede locomotion of the target. The current may ionize air in a gap. A gap may occur between terminals at a face of the CEW and/or between the electrodes positioned near target tissue. A CEW may include a detector to detect ionization of air in a gap. A CEW may use information related to detecting ionization to determine a location where the ionization occurred. Information regarding location of ionization may be used to determine whether the current was delivered through the target via the electrodes.