High-Voltage, Square-Wave Trigger Pulse Generator

Summary form only given. We present the principle of operation and performance a HV pulse generator designed primarily for the triggering of spark-gaps, although it can be used also as a standalone unit. Its nominal output voltage varies from 5 to 30 kV. The generator employs coaxial cables for charge-storage and pulse formation, and a thyratron as the switch. Two circuits are presented: 1) a single-stage one consisting of cable that is charged via its shield on one end and discharged with a thyratron on the opposite end, 2) an inverting stage employing a second coaxial cable. When the first stage is charged with a positive DC supply, a negative square pulse is obtained at the output on switch closure. The duration of the pulse can be controlled by varying the cable's physical length as the former turns out to be twice the single-transit time. The use of the inverting stage reverses the polarity of the pulse while retaining its basic shape. The rise-time obtained is mostly dictated by the switching time of the thyratron; with the one we used in the tests, rise-times in the range 30-40 ns were obtained. We also report the results obtained in triggering the capacitor banks of a large Marx and a plasma focus.