Re: Q - Driving HV DC pulses? (fwd)

["High Voltage list" <hvlist@xxxxxxxxxx>]

Original poster: <sroys@xxxxxxxxxxxxxxxxx>



---------- Forwarded message ----------
Date: Thu, 06 Oct 2005 20:54:12 -0700
From: Jim Lux <jimlux@xxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Q - Driving HV DC pulses? (fwd)

At 06:34 PM 10/6/2005, High Voltage list wrote:
>Original poster: <sroys@xxxxxxxxxxxxxxxxx>
>
>
>
>---------- Forwarded message ----------
>Date: Wed, 05 Oct 2005 18:38:30 -0400
>From: Jeff Bullock <jeff@xxxxxxxxxxxxx>
>To: High Voltage list <hvlist@xxxxxxxxxx>
>Subject: Re: Q - Driving HV DC pulses? (fwd)
>
>Hi Jim,
>
>Thanks for your reply.
>
>---------- Forwarded message ----------
>Date: Tue, 04 Oct 2005 07:36:57 -0700
>From: Jim Lux <jimlux@xxxxxxxxxxxxx>
>To: High Voltage list <hvlist@xxxxxxxxxx>
>Subject: Re: Q - Driving HV DC pulses? (fwd)
>
> > What are your requirements in terms of:
>
> > 1) Output current
>
>Very low current/high voltage.

Numbers??  low current is milliamps? 10s of milliamps? microamps?


> > 2) Pulse width
>
>Adjustable down to micro second intervals.

What's the max? How fine do you need to adjust?



> > 3) Rise and fall time
>
>As fast as possible.

nanoseconds? picoseconds?  faster is harder, as you know..


> > 4) repetition rate of the pulses
>
>Once again, adjustable.

But over what range?  1pps? 1 MHz?

> > 5) Jitter
>
>While laser power supply circuits may be a good fit to start with, the
>initial goal is to minimize timing deviations and produce regular, clocked
>pulses.

555s produce fairly low jitter pulses, or do you need some sort of counter 
driven scheme where you start with a high precision oscillator and count down?



> > How adjustable does it need to be?
>
>Its whole purpose is to be suitable for a wide variety of experimentation
>and therefore the output pulses need to be as accurately
>adjustable/measurable as possible.

What about using a commercial pulse generator that puts out lowish voltage 
pulses to drive a HV switching system?  That way you only have to tackle 
one problem.

> > FETs can do the job (you have to stack multiples in series).  So will a
> > variety of tubes.
>
>Do you mean in a Darlington, multi-step configuration?
Nope.. series configuration. you can get 1000V FETs, and you can drive them 
with capacitors or optos.


> > If you look around for "radar modulators" you'll find some information.
>
>Interesting idea.
>
> > An invaluable source is the Los Alamos National Lab report by William
>North
> > called "High Power Microwave Transmitters", which is available on the web
> > at a variety of places.
> > (http://hot-streamer.com/TeslaCoils/OtherPapers/NorthReport/)  Lots and
> > lots of useful design information.
>
>Good info. Thanks!
>
>Regards,
>
>Jeff