In this paper the measurements of the dynamic breakdownvoltages U b for linearly rising pulses in nitrogen at lowpressure are presented. The measurements were carried out for therates of voltage rise k up to $300\, {\rm V\,s}^{-1}$ . Dependence of thebreakdown voltages, delay times and electron yields on the rate ofrise were obtained experimentally and theoretically under different conditions. It was found thatthe overvoltage $\overline {\Delta U_b}$ and the mean effectiveelectron yield $\overline {YP}$ is proportional to $\sqrt k$ (Yis a number of generated electrons in the interelectrode space persecond and P the breakdown probability), while the statisticaltime delay $\overline t_s$ is proportional to $1/\sqrt k$ . In thesecond part, the experimental breakdown voltage distributions wereobtained, fitted by theoretical distributions and some breakdownparameters relevant to experimental conditions were determined.Based on the approximate analytical and numerical models, thedependence of the effective secondary electron yield γ onthe overvoltage and on the rate of voltage rise were derived fromthese measurements. It was found that γ varies linearlywith the overvoltage for a constant k, and the slope of γis proportional to  $\sqrt k$ .