Fusor Forums

The above will work with any neon transformer ever made. I stated this in the first lines of the FAQ. Read it again.

Ricahrd Hull

I have spent hours searching through the 15 years of history on this forum. I search a certain thing such as "spark plug feedthrough" or "neon sign transformer" and then go through every single post and response. However, I still have a few questions (probably because I am only 14 and this is the first time I'm dealing with this type of equipment).

My first question is how to hook up the 2 diodes in a series? I am probably over thinking it but I just want to be sure how to do it. Second, I'm still do not understand how to hook up the input voltage of a neon sign transformer. It is not a simply "plug into a wall outlet." I posted this same question not too long ago and was told to check the 15 years of history and FAQ's. That is exactly what I did, and yet I am still confused. While I am making this post I just have an unrelated quick question: Is hot glue air tight?

I apologize for these beginner questions however any help at all would be greatly appreciated and help a lot to getting my demo fusor up and running.

Sincerely,

Scott

Scott,

I can understand your frustration, but let me be absolutely clear about one thing: Fusors and other line-powered high voltage gear are emphatically not entry-level projects. You are going to need help--hands-on, experienced, adult help--to hook up that neon transformer safely. Our forum is actually full of advice on how to use NSTs, but the discussions assume a passing familiarity with general concepts in electricity, like what a circuit is, how a diode works, how a transformer works, and how to attach a power cord to equipment. The best way to learn those things is not on this forum (because, you're right, they aren't discussed), but under the tutelage of a competent adult.

Please let me know when you have someone to help out.

-Carl

I have deleted the five chatty posts after Carl's well thoughout admonition.

The rule is if you don't have anything to add in the way of correction or new information within a FAQ, please carry your discussion on outside of the FAQ in a new subject post within the relevant forum. FAQs are not a discussion forum.

Carl and all of us have stressed that each newbie be a "self-directed learner in all efforts related to those very elementary and basic things common to simple electricity and commonly understood to most amateur scientists. It is hoped that most attempting even a demo fusor would have a basic idea about simple circuits. A good amateur scientist, of most any age, should have a simple and basic underatanding of materials, chemistry, and electricity and be safety conscious. If he or she enters a realm of more complexity in one of these disciplines then they should head for a good book to bone up as needed. In this day and age, a Google search is often sufficient. Still, learning how to use and acquire a few key reference books for your own scientific library is of signal value.

Good, active amateur science demands you work with both your hands and your head.

Richard Hull

Hello Richard, sorry but I am not going to even try this until I fully understand what I am doing. So I have added on and I have had some very knowledgeable people on here telling me that your picture is incomplete so would this be right.

https://docs.google.com/document/d/1O43 ... 4Z-tE/edit

It will work just fine. I did not draw the fusor. The assumption is and the hot line is marked "to fusor grid". The grounds are also obviously connected to the fusor shell which is forever grounded. Your friend just connected the obvious lines.

Richard Hull

So no special procedures are required when attaching HV wires?

No, not particularly. They are just wires after all. The basic assumptions are:


1. You have the supply turned off or better still, unpluged!
2. You have selected wire that is insulated to the full extent of the voltage you are going to operate.
3. You can turn a screw or bolt to attach wires or solder them.
4. When routing high voltage wires, you allow pleanty of clearance around other objects and keep all such wiring from ever being touched once in operation.

All of the above is just common sense.

Over 30 kilovolts corona can become an issue and creates its own special remediation procedures. Few who land here ever go into this range as few who land here ever actually do fusion.

The ground wires are all just normal 16 gauge of larger insulated wires with normal household wire insulation. Only the hot negative high voltage wire to the inner grid from the supply needs to have special HV rated insulation.

Richard Hull

I have a quick question. For the voltage measuring circuit, why is the 1K resistor so precise? Will a standard 5% tolerance really have that large of an effect for measuring the voltage?

Not critical at all if you don't mind being a couple of hundred volts in error plus or minus. This is especially true with an analog meter, but if you use the digital voltmeter,(3 or 4 digit readout), pay absolutely no real attention to or place any value in the reading of half of the trailing digits.

I had some 1% 10 megs put in series on hand and many 1%, 1k ohms so I used them. The accuracy seemed important at the time. High accuracy in HV measurement on a demo fusor is just not needed, of course.

In real fusion above 20kv, a +/- 1000 volt error in your reading is of no real significance unless one is truly, anally retentive or planning on submitting a peer reviewed paper to a major journal.

Richard Hull

Alright, I was just making sure there wasn't anything I was missing. Thank you Richard!

Updated this thread with the first post's addition of the most simple possible demo fusor power supply diagram as well as a much more involved and complex hookup for those who might want to be in the plasma club with metering and filtering added and current limiting for a final supply that can even do fusion in future. July 2023

Richard Hull

I recently lost a HV diode in my bridge circuit (second time. Getting old. Haven't bothered to fix it with so much going on.)

Having a Neon Sign Transformer (NST) makes determining the bad diode rather simple. Just hook up one side of the NST output to my fusor input HV cable, and measure the diodes in the bridge.

So besides use as a demo power supply, a NST is extremely useful for testing very HV diodes (20 kV.) With a variac, could be used for lower voltage (1 kV and up) diodes, as well.