> "Can an unloaded tank reach potentials higher than the
> breakdown
> voltage of its Tune C?"
>
> Yes. We are not dealing with dc, but waves. These waves
> do not necessarily where you expect them or want them to.
> The peaks will vary depending upon the frequency and
> length of components. It might be easier to imagine
> standing waves on antennas. The same thing will apply in
> tank circuits.
Yes, but not for that reason in HF amplifiers.
You'll find, if you carefully investigate component
breakdown, voltage flashover point depends heavily on the
shape of the conductors at different potentials. This is a
very well known effect.
The same air variable can have a vastly different voltage
breakdown depending on the micro-shape of edges of the
plate, the amount of mesh, the humidity or air pressure, and
so on. I spent a long time looking at switches and other
components, and while I generally tried to pick an air
variable that broke down slightly before the switch that
often is not possible to maintain on all bands and with
production variations.
This is why a spark gap is so useful, but the gap should
NEVER be from anode to ground. That would dump the HV. The
gap should be from the tank input to ground. This is a
problem people have been fighting since RF transmitters were
first produced. When the load is removed or changed in
impedance the wrong way, or when the drive is suddenly
increased, tank voltages soar until something puts the
system back into equilibrium.
There isn't any magic involved.
73 Tom
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