DIY Electron Accelerator: A Cathode Ray Tube in a Wine Bottle

Step 9 Build and Hook Up the Power Supply

The cathode ray tube/gas discharge tube does not require any sort of specialized power supply. Any high voltage power supply that can produce over 10kV of potential difference will work. In fact, you can even use an AC power supply if you don't mind the electrons going the wrong way half the time.

The best type of power supply to use would probably be a (roughly) 20kV DC flyback transformer using a low current driver like a 555 oscillator and MOSFET. In fact, almost any of the "quick high voltage power supply" instructables we have here should work. However, I did not have a flyback power supply on hand when I was building this project, so I used a rectified neon sign transformer instead.

I've included an electrical schematic that shows how to hook the diode up to the transformer. One end of the transformer is hooked up to the cathode of the cathode ray tube, while the other end is hooked up to the anode of the high voltage diode (the triangle end). Then, the cathode of the diode (the vertical line segment) is hooked up to the anode of the cathode ray tube.The second picture is of the completed electrical setup and the last two pictures show the transformer and diode individually:

Comments

[Indegreen]

Hi Daniel-Good work, and very innovative with the wine bottle (be careful!). Where did the wine go? 2 things that may help. The tubing is outgassing while under vacuum and those gases are being ionized. After this, READ DANGER CAUTION: Unless you detach the center tapped ground on the NST internally, you are getting 1/2 the rated voltage from the NST. In your case-4.5kV. That ground is the true return path for current Floating the NST ground is not necessary, because what you have is enough to produce plasma. ***IF YOU detach that internal ground to get the rated voltage (don't do it!!!) , the case goes to full voltage potential and will/can kill you if you happen to touch the case. A floating ground NST should be enclosed in an insulated box (plastic tub can work). Please go to: http://www.fusor.net/board/view.php?bn=fusor_hvpower&key=1078245537&pattern=FAQ where you will find a much better description of what is going on than I can give. BE CAREFUL!!!

[Xellers]

Thanks for the comment!

I was considering removing the center tap on the NST, but I still need it to safely power my Tesla coil, and I don't want to lug it around in an insulated box. I used the NST/HV diode because that's what I had on hand. For my new cathode ray tube, I'm going to just build a super-simple flyback driver and get rid of the bulky, high current NST (30mA is way too much current for a cathode ray tube, so it needs lots of additional limiting, which is a pain).

As for the tube outgassing, do you have any advice on how to reduce that effect? From what I understand, cold cathode tubes actually need to operate in the region just before the plasma discharge extinguishes for electrons to be accelerated (sparkbuzzbang and my own experiments confirm this), but it would be nice to be able to get a lower vacuum for other experiments.

[Indegreen]

The besy way to solve the tube problem is to use stainless steel all the way from the pump to the CRT. This can be done with some adapter applications. You can use flexible SS vacuum tube also. Ebay! Your idea of using a 555 driven flyback will work. There are many, many great posts on both of these subject at fusor.net. The FAQ sections there are a great source of information on vacuum science, high voltage, mechanical construction, theory and much, much more. Be careful, though, that you do not become inspired to move on to a fusor project! It is basically what you are doing already, but on steroids! ;>}