In message <01BE707C.DDF04800@LABRAT>, George K. Watson
<watson@epiloglaser.com> writes
>
>I am surprised that in all of this now one has mentioned the class E topology.
>For CW only use it is perfectly adequate and can be very inexpensive.
>There are parts available now with switching times adequate for 30Mhz that are
>also high voltage (500-1kv).
>This means that it would be possible to rectify and filter the house supply
>and
>have full legal limit with about
>12-15W of drive. No transformer!. We are using this approach at the moment to
>pump a CO2 laser at 40Mhz. The cooling
>requirements are minimal and the parts are reasonable in small quantities
>($79.00). We are seeing 87% efficiency (counting
>the drive power) at the moment.
>
I'm intrigued - I thought that class E operation relied on the load
being well defined, with load VSWR tolerance being poor, especially if
you take advantage of the low dissipation to use small transistors in
the output stage. With a laser tube (and other plasma systems?) don't
you have to survive 10:1 VSWR before it strikes?
What power are you generating and what's the power rating of the
transistors you are using?
Steve
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