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Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
A Cockcroft and Walton generator driven by a large old-fashioned television AC Line Output Transformer ('flyback') can provide about 3mA @ 75kV (if it is well made) which is enough to run a dental X-ray tube at medium power. (I guess yours is a dental tube because of the voltage)
If you need much more current than that, you must be prepared to pay for it!
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
borri317 wrote ...
I hava ac flyback, 10 10kV 1n capacitors but i cant find diodes.
Several companies in China sell HV diodes through ebay at very good prices. I have bought from them and found them honest and the parts reliable. (Most of the world's electronic parts are manufactured in China nowadays)
Registered Member #664
Joined: Sun Apr 22 2007, 10:31PM
Location:
Posts: 13
I dont have paypal so i have to buy expensive diodes from shop. What parts i should use for zvs flyback drive? I tried it once with buk456-60a fets and 1n4007 diodes and i didnt work. Should i put some kind of resistors to voltage multiplier to protect diodes from too much current? Should i use 12kV 550mA microwave oven rectifiers or 25kV 25mA rectifiers?
Registered Member #1225
Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253
You are going to need faster diodes than those. Maybe a few strings of uf4007? Those are cheap, and 1kv at 1 amp. Though i am not sure that 10kv capacitors would be good. I would use higher voltage rating, chances are the LOPT puts out too high of voltage.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
Anything to do with X-rays has, in my view, to be constructed to a very high standard, so you'd be better waiting until you can get suitable parts than start off with improvisations which are likely to be unreliable.
You will also need some means of measuring the X-rays, such as an ionization chamber, proportional counter, or other dosimeter, (but not a GM counter) and an adequate amount of lead for shielding, a mirror trap, a 100kV potential divider to measure the anode voltage, and so on, before you can begin your experiments in safety.
A high voltage supply is the least of your problems here!
Registered Member #664
Joined: Sun Apr 22 2007, 10:31PM
Location:
Posts: 13
Radiation shielding is least of my problems. When i go to buy diodes i also buy resistors for that divider thing. What kind of diodes and capacitors i shoud use? I dont have 10kV 1n capacitors i have 15kV 1n capacitors.
Registered Member #1806
Joined: Sun Nov 09 2008, 04:58AM
Location: USA
Posts: 136
borri317, have you considered using an ignition coil? They're extremely easy to run directly off of the mains, and when doing so, produce significant output. As has been stated before, you do not need to rectify the power to the xray tube, as it will self rectify (that is what it is after all, an ultra high voltage rectifier)
I've not personally tried this, but it seems reasonable that it could work.
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electricity for x ray tube
