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ULTIMATE HVHF Amplifier

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rororo74

Thu Jul 23 2009, 05:08AM

Registered Member #1124 Joined: Fri Nov 16 2007, 01:42PM
Location:
Posts: 17

I know that many people are already experimenting in many different areas, but each experiment has to start all over again from the beginning due to power supply re-design.
This is why I am proposing a more-or-less universal power supply that can be used for almost any project, from Tesla coils, to lasers to plasma to battery-recharging bla bla bla.

Like myself, most people already have a capable function generator (or 555 circuit) and a neon transformer (or flyback).

Would it be possible for someone or a team to design a circuit (an amplifier) that:
1. Includes inputs for the function/pulse generator
2. Included inputs for the +/- of the transformer/s
3. Includes outputs for the amplified pulse â€“ must be fast (capacitors preferred) and able to handle high frequency pulse amplification up to the MHz range (say 5/10MHZ?)
4. Can accept input voltages between say 1KV to 20KV or more (for future expansion) (any advice?)
5. Must include protection for the pulse generator/transformers and for the circuit itself (you are the experts on this. I do not know what complications may arise)
7. Must be public-domain and freely available to everyone. The goal is to make it easier for everyone to experiment with pulsed HV. Therefore the more flexible the device, the better.
8. Very good quality components are a must for reliable performance. Should be common parts so that anyone can easily obtain them. Rare components should be avoided (if possible). Functionality should not be hindered by hardware chosen.

I think this would be extremely useful for a number of reasons.
1. People can use this at the heart of a multitude of projects
2. People can use their own pulse generators
3. People can use their own transformers/generators (whatever they find handy)
4. People can enhance the output by adding a second or third or fourth transformer in series??? (any advice?)

I think of this as the amplifier of a Hi-Fi component system, with the tuner (function gen), a power supply (the transformer) running the load!

issue: LOAD LIMITATIONS?

I am willing to be the first sponsor of the project and I hope that others interested will follow or support in any way they can.
What do you think people?

Steve Conner

Thu Jul 23 2009, 09:21AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Are you sure you don't want the moon on a stick while you're at it?!

I know of a few people here who've built what they call universal H-bridges or universal drivers, but what you want seems to be a tall order indeed.

rororo74

Thu Jul 23 2009, 01:50PM

Registered Member #1124 Joined: Fri Nov 16 2007, 01:42PM
Location:
Posts: 17

:) All in the name of progress! Why not? Universities and labs around the world are already playing with THz KV pulses, we should at least break the MHz barrier!
Is it technically impossible? Is the goal not worth it?
PLUG&PLAY&FREE4ALL!

GeordieBoy

Thu Jul 23 2009, 02:24PM

Registered Member #1232 Joined: Wed Jan 16 2008, 10:53PM
Location: Doon tha Toon!
Posts: 881

ar make linear RF amplifiers that are ideal for most test purposes. They are available to anyone with a sufficiently fat wallet!

The design of such a beast is not simple though. Especially if you want it to handle high voltage, provide significant power, have a wide bandwidth, be indestructible, unconditionally stable and preserve pulse wave shape! Good luck!

-Richie,

Steve Conner

Thu Jul 23 2009, 03:28PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Amplifier Research?

I've seen their stuff at EMC test houses, and it does look big and expensive.

I think the original post shows some confusion as to exactly what this device should be. For instance he talks of inputs to power it from a neon transformer. Well, you almost certainly don't want to do this! Because of the limitations of semiconductors, it's far easier to generate the pulses at a lower voltage (<600V) and then step them up with a pulse transformer. I've seen high voltage MOSFET and IGBT stacks up to 10kV, but they're expensive, unreliable and slow.

He also doesn't say whether the amplifier should be linear or not, which has deep implications. For instance an H-bridge, Class-E SSTC driver, or whatever, is not linear, but an audio amplifier is.

Also, there's lots of information in the forum and archives already, and it's all public domain (Creative Commons to be exact.) I've seen Class-E amps up to 14MHz, H-bridges up to 6kW continuous and >100kW pulsed, and so on. All it needs is someone to round all that info up, like the OP perhaps

My own personal view is that it's easier to have different power amps for different jobs. For instance, if you really wanted a THz, kV pulse, the easiest way to make it would be a laser. (Light is just EM radiation after all, so it has an E-field that you can measure in volts per meter or the like. A decent-sized pulsed laser can generate enough kV/cm to produce dielectric breakdown of the air.)

And you can't charge batteries with a laser.

HV Enthusiast

Thu Jul 23 2009, 05:56PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

rororo74 wrote ...

I know that many people are already experimenting in many different areas, but each experiment has to start all over again from the beginning due to power supply re-design.
This is why I am proposing a more-or-less universal power supply that can be used for almost any project, from Tesla coils, to lasers to plasma to battery-recharging bla bla bla.

What do you think people?

Not practically, nor is it really possible given real world limitations. Its kind of like asking someone to design a car tire that weighs nothing, is fantastic in foot deep mud, has fantastic handling at 200MPH, can stick to the pavement during the harshest of drag races - in ALL temperature ranges no less, and also be virtually indestructible. Oh yeah, and it has to cost nothing as well.

As Steve already said, its much easier, practical, and cost efficient to build a custom supply for the given application. Plus, no matter how universal you make a supply, its never going to fit someone's particular application perfectly. Thats just the way it goes.

Mathias

Thu Jul 23 2009, 07:34PM

Registered Member #1381 Joined: Fri Mar 07 2008, 05:24PM
Location: Hungary
Posts: 74

Practically speaking , why would anyone (who can't make such device with his given resources) need such device any how? By the given specs , most DIY people won't ever need to amplify kV signals in the Mhz range.
It's not an impossible task if you narrow down some of the specs , but then again why bother with such?

FastMHz

Thu Jul 23 2009, 07:37PM

Registered Member #179 Joined: Thu Feb 16 2006, 02:08AM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287

After thinking about the proposal for a while, I've come to agree with the replies here....trying to build a unit that does it all just isn't feasible. Jack of all trades, master of none. It'd be better to break it down into modules that rack-mount. Then, each part could be designed for each particular purpose that the OP mentioned, loaded into a rack, and you'd essentially come out in the end with a modular 'unit' that does all these things, but with dedicated circuitry.

Hon1nbo

Fri Jul 24 2009, 01:29PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

I have tried numerous times, and failed, at making a universal HV power supply - I tried multiple compact and adjustable drivers running through switching circuitry to multiple types of transformers and multipliers, but in the end you'll likely wind up with a mess of a project that is over-complicated, prone to problems, and in the end is not really all that universal
plus, parts end up conflicting unless you properly design something to counter that tendency - so nothing is really efficient, it ends up being much larger than you'd think, and frankly I find myself an idiot for trying!
while you can make "general" power supplies, you can't make a truly universal one due to the extreme differences in requirements whether they be voltage, load, frequency, size, tuning, or even the main power source

rororo74

Sat Jul 25 2009, 03:55AM

Registered Member #1124 Joined: Fri Nov 16 2007, 01:42PM
Location:
Posts: 17

Thanks to everyone of you for posting your opinions and please accept my apologies for not providing exact guidelines since I am still in the process of deciding what they should be. I think this post should clear some important requirements.

I do agree with your comments on the 'jack of all trades' points. Limitations will be set. The purpose I envisioned for this thread is to gather opinions on what spec and limitations could actually make this project feasible. I also know that you get what you pay for. It's all a juggling act.
I understand that I may have confused you a bit so let me clarify.
The ultimate goal I envision of this effort should be only one - High Voltage (>=1KV), High Frequency (>=1MHz) pulses.
I mentioned capacitors in my first post, because they can be discharged rapidly instead of using MOSFETS. My gut feeling tells me that capacitors should be used and this is why I am giving up on the idea of exact amplification of the pulse (generator signal will only be used as a timer - duty cycle controlled separately maybe).
Feasibility study anyone (have you seen something like it on the market)?
Go easy on me guys and thanks again! :)

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