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On 9/11/19 6:09 AM, Daniel Kunkel wrote:
Just curious about spark gap losses.
There are some discussions in the archives..
google site:pupman.com spark gap losses
for more details
What is the primary source of the
loss? I know some energy is lost through heat, light, and sound...do all of
those losses stem from the energy required to ionize a channel through the
air? Does the total gap distance (single or multiple) have anything to do
with losses?
Spark gaps have a voltage drop that is some fixed number (40-100 V)
(called the cathode drop) plus a thermal loss that is proportional to
the length and inversely proportional to the square root of current. The
cathode drop is affected somewhat by the material of the electrode and
its temperature (sthermionic vacuum tube with a heated cathode being a
nice example)
As the current goes up, the spark channel gets bigger in diameter - it
turns out free burning arcs tend to have fairly constant temperature
within the arc, so the arc expands until there's a balance between the
power being dissipated from the current through the arc and the power
lost through radiation/conduction to the surrounding air.
So a multigap will have a higher voltage drop (and loss) than the same
total length as a single gap. However, because multigaps cool/quench
better, that's why they're popular for static gaps.