Plasma Globe Circuit

[George L.]

Hello,

I am trying to make a simple plasma globe out of a lightbulb....here is an example of what I am trying to make: https://tacashi.tripod.com/elctrncs/splglobe/splglobe.htm

I have attached a circuit that I am using to get very high voltage.

The problem is it will not work! I tested the circuit up to the first transformer and it outputs 320V. The transformer is from a camera, where it was used to create the "flash." Nothing will come out of the second transformer, which is also from another camera.

Also, the entire circuit become VERY hot, is this normal?

please help,

George

 

[zachtheterrible]

320v doesn't sound like it would be enough . . .

I would think it should be a couple kv but im not sure?

NO! circuit getting hot is not normal. The transformer may get hot, although w/ a 4.5v supply I doubt it. The 555 definetly should not get hot though.

 

[Oznog]

Not only is 320v not high enough, but 300 hz is far too low.
You need something in the range of several kHz, and that type of iron core transformer will not operate at these frequencies.

You must have a flyback transformer here.

 

[George L.]

i don't think I explained correctly......

there are two transformer is my circuit, the first one has an output of 320, the second on doesn't work but it should pump it up to about 22,755V.

All I have to do is change a resistor to make the frequency a few KHz.

Is there a way around using a flyback transformer, I already made the circuit! :cry:

thanks,

George

 

[moody07747]

as for a high voltage power supply here are a few i know of

https://www.aaroncake.net/circuits/hvgen.htm

https://www.aaroncake.net/circuits/lasersup.htm


looks like a kool project

 

[audioguru]

What makes you think that the output of the LM555 is a 4.5Vp-p square-wave? With a 100mA load, you will be lucky to get 2.5Vp-p. Look at its voltage loss on its datasheet. The two transformers are probably trying to draw a lot more than 100mA.

Doesn't the battery voltage drop to less than 4.5V when the LM555 is driving one or both transformers? Its absolute minimum supply voltage is 4.5V.
Its output might saturate better, or blow-up quicker, with a higher supply voltage.

Doesn't the 320V output of the 1st transformer drop, maybe to nothing, when the 2nd transformer is connected? Then it is overloading the LM555 and the 1st transformer. Since the LM555 gets hot, it's overloaded.

Where is the reversed diode across the primary of the 1st transformer to protect the output of the LM555 from the very high negative inductive kickback voltage? Without the diode, does the LM555 still work?

You were trying to measure a very high voltage. Does your meter still work?

 

[Oznog]

i don't think I explained correctly......

there are two transformer is my circuit, the first one has an output of 320, the second on doesn't work but it should pump it up to about 22,755V.

All I have to do is change a resistor to make the frequency a few KHz.

Is there a way around using a flyback transformer, I already made the circuit! :cry:

thanks,

George

What's this second transformer?

What I'm saying is that first transformer probably can't pass signals of the needed frequency. A plasma globe runs like 25kHz-40kHz, the high frequency AC is essential to making streamers form. That iron core flash transformer is made for a few kHz, going higher makes it terribly lossy and the power output is insignificant.

Typically the fixed freq flyback transformer has one leg of the primary tied to say 12v, and a transistor switches the other leg between grounding it and letting it float. Note this is different from driving it "high". You need a transistor capable of around 50v for this since the flyback voltage is higher than the source.

 

[bryan1]

Just a thought bloke's the circuit I posted under the electric fence thread, outputs 3.6 KV. I wonder if the circuit slighly modiefied would do the job as it's based on a 555 along with an op-amp or I could be wayout on this one.

Just a thought Bryan

 

[George L.]

so much info... (thanks for helping everyone)

I got the 555 IC circuit from this site: **broken link removed** (On the menu list its the third one.)

as you can probably tell ... I am a newbie.

My multimeter only mesures up to 500V AC and 500V DC. I touched what should be 22,500 volts to my tounge :wink: and felt nothing (sort-of a good thing)

Oznog,

What you are saying is I can fix the circuit by adding a transistor? I'm a bit lost. :?

Audioguru,

I can use whatever voltage would work, I just chose 4.5 because thats what I had laying around the house. I tested 320V when I had not yet put the second transformer into my circuit.

please help(a bit more :lol: :lol: )

thanks,

George

 

[Nigel Goodwin]

My multimeter only mesures up to 500V AC and 500V DC. I touched what should be 22,500 volts to my tounge :wink: and felt nothing (sort-of a good thing)

I sincerely hope you were joking? - assuming you weren't?, you're VERY lucky that it doesn't work!. The low current available from the battery probably isn't enough to kill you if you touched it (with your hand) - but touching it with your tongue increases the danger many times, and would be an EXTREMELY!! stupid thing to do.

BTW, if it was generating 22,500V, even off the small battery, touching it with your hand could quite easily break your arm!, or your NECK! as you fell over.

I can use whatever voltage would work, I just chose 4.5 because thats what I had laying around the house. I tested 320V when I had not yet put the second transformer into my circuit.

please help(a bit more :lol: :lol: )

You can't just stick another transformer on the output of the first one - unless it's designed for that purpose - in this case as your first one is giving around 300V out, the second one would require a 300V primary, and a 22,500V secondary. Using a low voltage transformer backwards (which I presume you were doing) would have far too low an impedance to work, the second transformer would appear as a short circuit to the first one, and in your case would prevent it working.

Considering your lack of experience, and obvious lack of electronic knowledge, I consider it rather foolhardy to be playing with dangerously high voltages - it's not a job for beginners!.

 

[George L.]

Nigel...I was kidding about touching it to my tongue, I used one finger to do this ... this won't be bad even if I wet a shock... it will just hurt.

basically, what everyone is trying to tell me is that this circuit won't work?

If someone could please provide me with a simlpe schematic that I could use for the plasma globe, it would be really helpfull. If you could modify mine it would be REALLY awsome.

thanks,

George L.

 

[George L.]

Nigel wrote:

the second transformer would appear as a short circuit to the first one, and in your case would prevent it working.

thats the problem! How can I fix this?

thanks again,

George

 

[Nigel Goodwin]

Nigel wrote:

the second transformer would appear as a short circuit to the first one, and in your case would prevent it working.

thats the problem! How can I fix this?

Build a proper circuit for it!, the original website you quoted gives full details of how he made his plasma power supply - why don't you simply copy that?.

As various replies have already told you, you need high frequency for this to work, and mains transformers won't work at high frequencies. Also, you are trying to drive it from a puny 555, the plasma article you quoted says his takes 2-3A at 24V - you don't have anywhere near enough power capability!.

 

[George L.]

ok forget the plasma globe part.

I just want 22,500V at a normal frequency, 60Hz. That is good enough for me. Lets forget about the high frequency part. I just want to get my circuit to work.

The problem has been identified by Nigel:

Using a low voltage transformer backwards (which I presume you were doing) would have far too low an impedance to work, the second transformer would appear as a short circuit to the first one, and in your case would prevent it working.

I said I was using a camera flash transformer which normally takes 1.5V and turns it into 330V. I wanted to use two of them to get 22,500V.

please help me fix my circuit,

George

 

[audioguru]

You need a very high power driver and a transformer designed to turn 1.5V into 22,500V!

Neon signs have a transformer that is powered from the mains with a very well insulated output of 12,000V. Isn't that enough to kill yourself?

 

[Someone Electro]

Photoflash caps are normal 100uF 200V caps they have an circuit conected to it that bosts the voltage and charges them whith it.

It wod be beter to use an neon seign transformer or an TV flaback transformer.


I dont sugest you doidng so high voltage stuff since you dont have much electronics knowlege

 

[chiba]

With some changes to your circuit and a few extra components i could show you how to get some decent sparks. I'm a little concerned that you may test it with you tongue though.

ok forget the plasma globe part.

I just want 22,500V at a normal frequency, 60Hz. That is good enough for me. Lets forget about the high frequency part. I just want to get my circuit to work.

...

please help me fix my circuit,

George

 

[chemelec]

It Won't work properly at 60 Hz.

Those are High Frequency transformers you got out of the cameras.

And Even if you were to get it to work at a Higher Frequency, the Current output will be TOOOO LOW.

 

[chiba]

you could un it at ~15KHz, use that to switch a TIP31 and then You could just use a Villard Cascade to get it up past ~20KV. If his 4.5V has the current then some serious zaps would happen. But, like i said before, i don't want to post a schematic of a potentially harmfull circuit to someone who checks high voltages with their tongue! :roll:

 

[lee_76]

plasma globe

hello,im new to this site,but seen a problem with your circuit straight away(even though it wont work anyways) but one of your resistors is too low a value, they must be a minimum of 1k on the 555 timer,could be why its getting warm,not sure but just a suggestion!