Contents
What decides the spark gap?
At typical pressure and electrode distance combinations, Paschen’s law says that Townsend discharge will fill the gap between the electrodes with conductive plasma whenever the ratio of the electric field strength to the pressure exceeds a constant value determined by the composition of the gas.
What is purpose of spark gap?
Spark Gaps. Gas filled spark gaps are high energy, voltage controlled switching devices, unique in their ability to repeatedly switch currents of thousands of amperes. They are ideally suited for diverting large electrical surges caused by lighting, EMP and other sources of high voltage, high current transients.
How many volts does it take to make a spark?
“High voltage from 15,000 volts to 20,000 volts is needed to make the spark.”
Why do we need a triggered spark gap?
Triggered spark gap design boils down to two things: theory that explains how and when gas turns to plasma and engineering details about initiating that transition. The Townsend discharge process explains how gas is converted to plasma and Paschen’s law predicts the conditions needed for this transition to happen.
Are there two or three electrode spark gaps?
Even though two-electrode spark gaps can be triggered, the extra trigger electrode means that three-electrode spark gaps are usually called triggered spark gaps. There are many possible geometries of trigger electrodes. The two most common are the midplane and trigatron.
How are spark gaps used to achieve low jitter?
Triggered spark gaps are a class of devices with some additional means of triggering to achieve low jitter. Most commonly, this is a third electrode, as in a trigatron. The voltage of the trigger electrode can be changed quickly because the capacitance between it and the other electrodes is small.
How is a spark gap used in a Marx generator?
Spark gap pressure is held constant and you just wait for the pulse generator output to exceed the breakdown voltage predicted by Paschen’s law. This technique is commonly used to speed up the rise time of a Marx generator and a two-electrode spark gap used in this way is called a self-breaking or overvoltage spark gap.