Spark Gap Dynamics and High Voltage

1. Spark gaps have been used as high voltage, high power switches for many years.

2. Switch loss, defined as the amount of energy deposited in the switch during the switching process, is mainly a result of gas heating due to the finite resistance of the arc channel.

3. There are two distinct phases which characterize the formation of an arc.

a. Phase 1: current begins to flow while the arc resistance is relatively high. Resistance decreases to a finite value as the arc develops and expands.

b. Phase 2: known as the conduction phase, the arc resistance stabilizes at a low but finite value

4. Resistive losses occur during both phases, but these losses can be especially significant during the formative phase. (resistance of an arc ranges from tenths of ohms to several ohms)

5. The I-V characteristics obtained during spark gap studies indicate that the peak spark gap current is not a function of the gas mixture in the gap.