Abstract: A pulse generating circuit utilizes a drift step recovery transistor to apply power from a direct current power supply to a pulse forming network when a trigger pulse is applied thereto. The pulse forming network comprises a storage inductor connected in series with the transistor, a series connected separating diode and a drift step recovery diode which are connected in parallel with the storage inductor, a series connected pumping inductor and pumping resistor which together form a pumping circuit connected in parallel with respect to the separating diode, and a load resistor. Current passed via the transistor increases in the storage inductor and the pumping inductor and is blocked by the separating diode to inject electron-hole plasma from the pumping inductor into the drift step recovery diode when the transistor is conducting.