high voltage high frequency H-Bridge

[Archangel]

It's for an experimental rf heating device.

Mmmmmm . . . 450v x .040 amp = 18W not going to heat very much with that . . . Why does it have to be a square wave ? Seems like a class c rf amp would do what you want if sinewave driven. . .

[George]

well - yah, it doesn't have to be much power, I was only wanting about 10W of heat at this stage. One of the most important things is it's able to be made cheaply and reliably. I't doesn't have to be a square wave, a square wave is just preferable as it's kind of like a higher duty cycle. I have thought about RF amps but cant seem to find any small cheap ones that can do that voltage.

So yah - ideally i'd like to transistor (bipolar or FET) switch it but it's just getting the Gate/base voltage up there.

thanks

[Melanie]

Most MF/HF Amps are designed to work into a 50 ohm load... so you're looking at a 4kW device to give you the voltage you want.

40mA 450V at 1MHz is still 20W of anybody's money... easilly doable with a single 807 or 6146 valve... but the plate Transformer will set you back $100-$200.

Look on eBay for old Heathkit AM Ham HF Transmitters (from memory they all had American Indian native names I think). Nobody plays with AM anymore since they discovered SSB goes further. Those old 'Boat-Anchors' go for a song... and are a goldmine of parts you just can't buy anymore.

Oh... if you achieve it with a square-wave input, let me know... I want to set a stop watch to see how long it takes for the FCC (or NZ's equivallent) to break-down your door...

[Dave]

Melanie,
Quote" Nobody plays with AM anymore since they discovered SSB goes further."

You should live in the US.... Much better audio....

Dave Purola,
N8NTA