The influence of the magnitude of network parameters on the waveform generated by the simplest types of circuit used in high-voltage impulse testing has been discussed at some length in the literature. These treatises are based, however, on simplifying assumptions not absolutely necessary, and no attempt appears to have been made to develop a unified approach to this problem. Moreover, some important circuits of slightly greater complexity have received particularly scanty attention, ostensibly on the grounds of mathematical complication.The present paper introduces a unified treatment, without approximations, and with application to the more complex as well as to the simplest circuits. It indicates how one of the former may be employed to achieve higher efficiencies, coupled with increased economy of parts, particularly where resistive potential dividers are used. Some light is also thrown on the discrepancy between the nominal and actual rise times of double-exponential impulse waves.