Time-Resolved Current-Voltage Measurement of Spark Breakdown in Liquid N-Hexane

Measurements of the temporal variation of voltage and current in the spark discharge of liquid n-hexane were carried out. A dc voltage, which increased linearly in time, was applied to a test cell with tip-plane electrode geometry. By careful mechanical design of the test cell, a defined wave impedance of the whole experimental set-up was realized. A capacitive voltage divider was integrated into the HV feed to the tip electrode and the plane electrode was connected to ground via a coaxial measuring resistor. Data were taken for 1 and 2 mm electrode separation and for both polarities of the tip electrode. The temporal variation of the spark resistance R(t) was calculated and a general equation for R(t) was derived.