Many novel nanosecond pulse circuits with nanosecond rise time and high-repetition rate using step recovery diodes are discussed and recommended in this paper. The physical mechanisms of these circuits are described qualitatively by using the charge storage concepts and theory.The circuits discussed in this paper are divided into three groups: the pulse forming circuits which transform high frequency sinusoidal waves into nanosecond pulses; the pulse shaping circuits which transform pulses with slower transient response into pulses with faster transient response

and the pulse generator circuits which make use of the step recovery diodes combined with other high-speed semiconductor devices.The inherent capability and importance of the step recovery diodes in the nanosecond pulse circuits are well illustrated by the discussion of various circuits developed in this paper. Other types of new pulse circuits using step recovery diodes with more detailed analysis and practical circuits will be reported in the near future.