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.