Win's next 10kV project, a 1us ramp

Guess it's going to be a stack of FETs...

--
 Thanks,
    - Win

Sounds like it.

Instead of a stack of fets and a 10KV supply, might it be possible to sort of stack stages, and run each one from a charged cap (sort of a controlled Marx?) or maybe individual dc/dc converters, maybe a dozen stages at 800 volts each?

John

Plenty, though none off the top of my head. *Peruses ARRL Handbook*

4-1000A? 6kV max. plate, not quite enough although that's probably for transformer output, so peak would be in the 12kV range, same as your application.

Wait, "practical" triodes? Are you pulling my leg? ;-)

Tim

-- Deep Fryer: a very philosophical monk. Website:

Hey, cool:

Max plate voltage 4000, but if you look at the amount of vacuum in there, I'd go for lots more.

4 amps Id (er... Ip) with about +350 on the grid *and* the plate.

Cout probably in the 15 pF range.

And needs a mere 10 volts, 10 amps for the filament.

I have a couple, and they're beautiful hunks of glass.

John

Or a nice Russian hydrogen thyratron, except that Win has to control the slew rate somehow.

John

Hello John,

Is that available online? I could only see literature on scholar.google that quoted RadLab.

Anyway, I was thinking about those ballast triodes in earlier color TVs. If there is any chance to find one, that is, without having to rent a backhoe and dig through a landfill.

Regards, Joerg

Hey, Don, you're probably the reason I went into electronics.

Thanks for all those wonderful construction articles over the years in Popular Electronics. I still use some of the little test circuits I built from your articles.

Have a great new year.

Steve.

--
Steven D. Swift, novatech@eskimo.com, http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC.      P.O. Box 55997
206.301.8986, fax 206.363.4367  Seattle, Washington 98155 USA

Hello Win,

Yes, even 30kV. 6BK4 or Telefunken ED500. Possibly Svetlana still makes the GP-5: http://216.87.144.102/svetlana/pdf/GP5.pdf

They may be hard to obtain unless you settle for a few used ones. Such tubes were employed as regulated ballasts in early color TVs to keep the HV from varying. IOW huge shunt regulators. That was back in the days when electricity was considered to be almost free and nobody was too concerned about x-rays. Later they went to a separate HV generator instead of using the deflection flyback.

Regards, Joerg

When I will need your advice, I will certainly ask for it.

VLV

"Joerg" schreef in bericht news:Qjzvf.45284$ snipped-for-privacy@newssvr13.news.prodigy.com...

You're not going to tell me that you replaced it? ;)

--
Thanks, Frank.
(remove \'q\' and \'.invalid\' when replying by email)

"Nick

** The power or heat dissipation has to be estimated.

** Just multiply the current by the voltage ACROSS the LM7815.

ie Current x ( Input volts - 15 )

If the answer is less than 0.6 watts - you can forget the heatsink.

Otherwise use the " calibrated finger test ".

If YOU go "ouch !! " then it needs one.

......... Phil

At these relatively modest currents but high voltage he should look to SuperTex. They have more than a few patents on virtually blow-out proof inventions in this area.

That would be divided by the number of FETs...phew.

A transformer is what he might use- say a composite 1:100 with 10 primaries delivering 10A each from ~100V supply common 3kV reference for primary and secondary and output voltage galvanic feedback connection for linearization.

I think i suggested a flyback transformer. Adjusting the supply voltage on the inductor (primary) can adjust the slope / slew rate; maybe to 1% without too much trouble and the amplitude can be controlled by the gated time - again (perhaps) within 1%. One can easily have multiple KV insulation between primary and secondary (ies). And multiple drivers are not that big of a deal either.

What has to be 5%, maximum deviation of best fit ramp to actual, or total ramp time? And then when you attain 10KV what happens?- discharge any old way?- hold it? Sounds like you're going to be doing some serious study of transient thermal response curves, something is going to be dissipating 10KW peak. View in a fixed-width font such as Courier.

. 13kV . | . . . . . . | . .------------|\\ |- MOSFET stack . | | >---|< source follower . | .-|/ |- . | | | . --- '---------+ . - Vcompliance | . | floating | . | | . | | . +-------------. | . | | | . | | | . --- | | . - | | . floating | .-----|\\ |- . gate supply| | | >---|< . | / \\ .-|/ |- . | ~~ Vgen | | | . | \\ / '---------+ . | | | | . | | | [Rs] . | | | | . '------+------+------+---- . | . --- . --- . | 3kV . ------------+--------- .

I've heard trans-it-or from non-native English speakers...

A transformer is what he might use- say a composite 1:100 with 10 primaries delivering 10A each from ~100V supply common 3kV reference for primary and secondary and output voltage galvanic feedback connection for linearization.

I think i suggested a flyback transformer. Adjusting the supply voltage on the inductor (primary) can adjust the slope / slew rate; maybe to 1% without too much trouble and the amplitude can be controlled by the gated time - again (perhaps) within 1%. One can easily have multiple KV insulation between primary and secondary (ies). And multiple drivers are not that big of a deal either.