The concept of physically based distributions used in studies concerning gas electrical breakdowns is introduced in this paper. The non-stationary exponential distribution of the breakdown voltages and time delays with time dependent distribution parameter is theoretically derived based on physical grounds starting from a binomial distribution for electron occurrence in the interelectrode gap. The experimental distributions of breakdown voltages Ub and time delays td are obtained by applying linearly rising (ramp) voltage pulses to the discharge tube with a hard galvanic layer of gold on the cathode and modeled by multi-component non-stationary exponential distribution, as well as by a Weibull distribution for the sake of comparison. In order to fit the experimental data, the multi-component voltage/time dependent distribution parameter YP is introduced, where Y is electron yield (number of generated electrons in the interelectrode gap per second), and P is breakdown probability (the probability of one electron to cause a breakdown). It is shown that multi-component non-stationary exponential distribution is suitable for modeling of the experimental data when time varying voltage pulses are applied to the discharge tube.