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Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
The only other thing that I know of that is fast discharge related would be an old Quantel laser supply.
There was another thread on pulse shaping with certian coil values, it sorta looked like a delay line. I dunno if you can get that up to 1MHz but you could try that.
For 2KW you'll probably need a thyratron and a bulky power supply. I dunno if that will go to 1MHz because what you're asking for is a pretty tall order. 20KHz would be reasonable in comparison.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
Thanks for the info hazmatt!
Now, when you ask whether an amplifier will "work at 1MHz" you need to be careful. To me, that means that it can amplify a 1MHz sine wave at its rated output power without burning up.
That does not mean that it can reproduce a nice looking 1MHz square wave, or a pulse train with 1MHz PRF. To preserve the shape of a waveform you need the harmonics, so the 1MHz square wave needs 1, 3, 5, 7, 9MHz and so on. The third harmonic is considered an absolute minimum if you want to call the output a "square wave", so our amp would need a 3MHz power bandwidth.
Similar considerations apply to pulses. When you say "MHz pulses" or whatever, what do you really mean? A PRF of 1MHz? A risetime of 0.35us? Etc. All these questions need answered before you even touch the soldering iron.
Registered Member #1124
Joined: Fri Nov 16 2007, 01:42PM
Location:
Posts: 17
Please excuse me for taking a few hours to reply each time. I follow up on the info you give me. Hazmatt, I briefly looked into the laser supply you mentioned. Searching around led me to this: which I found interesting. There is no mention of voltage and I do not know if I require a so called network to run it. Are any of you familiar with these megatron power supplies? Steve, I know I most probably frustrate you with my quest so let me clarify further. I am looking for a power supply to power a new project. I do not know exactly how much power, volts, amperes or frequency I need. What I DO know is that it must be pulsed DC. The higher the frequency the better, but it must be over 1MHz. Also it must not be a sine wave. It should have a very high rise time preferably due to capacitive discharge. Pulse train or square wave or a series of spikes, may all work to varying degrees. I will not know until I try! Obviously I also have no idea about the duty cycle needed. A sweet spot will probably be found upon testing. I also know that voltage should be high. 1KV is a good starting point. I will know the exact load impedance soon but a rough estimate tells me that 2KW should be more than enough. Based on the prices I saw on the net I guess I could find something that fits the bill for around $5000 or less.
Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
Well.. if you're looking for a solid state spark gap, Terry's SISG setup is probably the closest thing you're going to find out there.
Otherwise if you want fast pulses with a low duty cycle, which is what you're asking for, maybe 2-20%, then you need to constrcut either a flyback, half or full bridge driver designed as a pulse generator that will meet your specifications.
Spark gap switching above 1MHz may be possible, but you have to consider charging time as the biggest delay in your system. 2KW of stored energy capacitivly will take quite some time to charge unless you are using expensive doorknob capacitors, a 5KW power supply (to charge real fast), and a specialized HF HV discharge switch that can operate that fast, like a really expensive SCR or specialized Thyratron.
If you need more information from your source you posted the link to, just give the company a call and talk to one of the design engineers. They're pretty good about answering questions like output, duty cycle, stuff they have to tell their customers.
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