The firing characteristics of a triggered vacuum gap below 1 kv

While the triggered vacuum gap is well suited to performing switching functions at high voltage, its high current-carrying ability, low arc drop and relative ease of firing make it useful at low voltage as well. The firing characteristics of this device were therefore studied in the range 100 to 1000 volts. Results showed that the gap could be consistently fired with a trigger current of 10 amperes in a time less than a micro second. Although little or no dependence of firing time on the voltage across the main electrodes was found, at least 250 volts across the main gap was required in order that a stable metal vapor arc could be reliably established. Throughout this study the polarity of the trigger current as well as that of the main gap. voltage were found to have a marked effect on the firing characteristics at low voltage.