Fig. 4
From: Human detection thresholds of DC, AC, and hybrid electric fields: a double-blind study
Sensitivity indices d′ under 30% and 50% relative humidity of a subgroup (n = 24): a DC EF and DC EF with ions. Ion current densities were 80 nA/m2 at 14 kV/m, 200 nA/m2 at 22 kV/m, 300 nA/m2 at 30 kV/m, and 400 nA/m2 at 38 kV/m; b AC EF; c hybrid EF: various DC EF (x-axis) with a constant AC EF of 4 kV/m; and d hybrid EF with ions: various DC EF (x-axis) combined with an ion current density of 10 nA/m2 and a constant AC EF of 4 kV/m. Bars reflect SDs