In this letter, experimental characterization and behavioral modeling of an off-the-shelf damped sinusoidal wave generator operating at different frequencies are addressed. Two modeling strategies are developed which lead to an active and a passive circuit representation of the generator, whose involved parameters are optimized by making use of time-domain measurement results obtained with the generator connected to different load impedances. It is shown that either the active or the passive model can assure accurate prediction of the generated waveforms, depending on the specific frequency. The proposed models can be effortlessly implemented in common circuit simulators, and used for systematic design of injection devices for transient con...