Hi Mads, just passing by and seeing this now, but if you need some info I have been working in the past with Wonderware products quite extensively and while it was a long time ago, some things may still apply... it was InTouch 10 + Archestra 7.x if I'm not wrong, but it must have evolved quite a bit

Have a look at Vicor Flatpac power supplies, there are some 36V or 28V ones on ebay and sometimes they can be cheap

Thanks Dave,

This is what a low inductance bridge looks in my mind (I'm used to discharge physics a bit)

Simply when you cobble something together on the desk you usually don't think to do it like that the first attempt

Here I'm working iteratively, I just put some mosfets I had planned to use for low voltage tests to compare with the 10nF caps I had put previously and noticed that driven capacitance was not at play there and my GDT was probably fine as the damping resistor value did not play a role either

I'll make two separate modules, and the bridge will be made on some spare double sided FR4... thanks for putting this back in my head

Hello there,

It has been some time since I did high voltage experimentation and I wanted to start over again...

I'm putting together a simple SSTC for fun and have designed a simple driver from a 4046 oscillator for variable frequency 50% duty cycle oscillator, CD4049 for phase splitter, and UCC27321 pair driving a capacitor coupled GDT for a simple half bridge

So far so good, the oscillator and driving part are working OK but I'm facing the traditional GDT issues with blowing UCC27321

I've gone the try and error route to have a GDT that will not fry everything but still have the lower UCC heating a bit, and a sawtooth ringing at the top of the mosfet gate signal...

Anyone would have pointers on the reason of this ringing which takes all the top waveform without damping over time? GDT core is unknown material but 10 turns of CAT5 cable goes 0.29mH (I also have others with nanohenries which seemed not ok to me)

Pictures attached :

https://www.befr.ebay.be/itm/Coherent-LIO-Surgical-Laser-Ophthalmoscope-working/122418247292?hash=item1c80b2367c:g:tYwAAOSwSlBY2aOd

If one of you wants to have a good teardown and score some good hardware... the price cannot be beaten!

I use an unfocused bluray laser pointer (10-20mW is sufficient) with an expending lens attached, it cures in a couple seconds... just use googles for not getting blind... dirt cheap and efficient

CFL inverters make good small power supplies for GM tubes

current limiting may or may not be good with valves... in the case of a small preamp this is OK but if you add it on the same B+ transformer than a push-pull for instance, current variation will give global DV variation and gain/operation points of preamp will vary accordingly, preserving proportionality

I'll be interested if you elaborate on the mosfet and produce a working circuit, I'm into valves right now too but something specific that I'll document when a prototype will be running

Thanks a lot

Aren't they a bit large for my use? I would say they could easily go up to 500W and more no?

Hi all

For a prototype I'm developing I would need some transformer cores with forms for 200W max, maybe 300W, to be used in a ZVS type oscillator

Anyone has some in stock, or a small range of spares that he would be willing to sell?

Thanks a lot!