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Beggining to High Voltage and Flyback drivers... Some doubts...

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Heitor

Tue Oct 27 2009, 09:57PM

Registered Member #2449 Joined: Tue Oct 27 2009, 09:39PM
Location:
Posts: 2

Hi,
I made my first flyback driver, was the most simple circuit, with a single 2N3055 transistor. It was cool, but not much eficient...
My doubts:

1) What is the most eficient/better transistor to use in this circuit??

2) Is a circuit with 2 transistor better/with more HV????

3) The HV is AC or DC???

4) Can I use it to power a Tesla Coil????

5) I want to build a ZVS driver. Is the components listed in this picture good for it???

6) This ZVS can power a Tesla Coil???

I'm beggining with High VOltage so I don't know much about it yet...

Thanks!!

doctor electrons

Tue Oct 27 2009, 10:15PM

Registered Member #2390 Joined: Sat Sept 26 2009, 02:04PM
Location: Milwaukee Wisconsin
Posts: 381

Welcome!
The first thing i would suggest is this. If you are new to high voltage projects, do as much reading on safety as you can. This way
when you are more familiar with what you are doing, you will be able to do it safely. I can't stress that enough!
Second, look a little further on the forum, i am sure that you will find some information on flybacks and such. It is not a new topic.
If your main goal is to build a tesla coil, or something to power a tesla coil, check out the tesla coil threads! Awesome stuff in there!!
There are very qualified people here that can answer all of these questions! Good luck with the project, and again, Welcome to the forum!!

Mads Barnkob

Tue Oct 27 2009, 10:17PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

â€ Heitor â€ wrote ...

1) What is the most efficient/better transistor to use in this circuit??

The problem with the 2n3055 driver you are talking about, if I am guessing right, is that its not built to being able to drive MOSFETs that would have the ratings. Its better to move on.

â€ Heitor â€ wrote ...

2) Is a circuit with 2 transistor better/with more HV????

A push-pull or half bridge driver will be more effective as it can handle a larger current and you have better control through PWM ICs

â€ Heitor â€ wrote ...

3) The HV is AC or DC???

Depends on the flyback, most new monitor/tv flybacks have a internal diode string so its DC. For AC flybacks you have to find some from old TVs, usually they are round and missing the screen/focus resistor networks you can see on those from monitors/tv.

â€ Heitor â€ wrote ...

4) Can I use it to power a Tesla Coil????

Yes you can.

â€ Heitor â€ wrote ...

5) I want to build a ZVS driver. Is the components listed in this picture good for it???

You linked to schematics I made for the version I built of Mazilli's driver, its good for longer runs at 400W input power at 36VDC.

â€ Heitor â€ wrote ...

6) This ZVS can power a Tesla Coil???

Yes it can.

â€ Heitor â€ wrote ...

I'm beggining with High VOltage so I don't know much about it yet...

Its a great hobby and I for one started exactly where you have :)

I made a small 24kV marx generator from a 4kV switch mode NST first, then I made the 2n3055 flyback driver that later powered my tiny spark gap tesla coil.

Proud Mary

Tue Oct 27 2009, 11:37PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Hello Heitor, and Welcome to the High Voltage World.

All of your questions are answered many times over in previous posts on our site, so it always pays to search for answers before raising the subject as a thread.

However, as you are just starting out with us, here are the answers to your questions:

1) 2N3055 is good only if you have nothing better. It is an old, inefficient technology.

2) Yes, two transistor will generate more power than one.

3) This depends upon the type of Line Output Transfromer (UK formal:"LOPT" - US informal: "flyback") that you have. In general, LOPTs
manufactured after about 1970 are of the "diode split" kind. In this topology, this means that the high voltage secondary is split into three or four independent winding each joined together by a semicondctor diode, so adding the output voltages of each winding together.

Joined as they are by diode rectifiers, the output of this kind of LOPT is DC. Nearly all are completely encapsulated in a black plastic block, so nothing of the diodes can be seen.

The older type of AC LOPT - dating back to the Thermionic Age - is generally supported by one or two Paxolin sheets (a brown early PC board) , and the HV output comes from the very obvious secondary. Such LOPTs are hard to find nowadays, but are the most popular
with HV amateurs because the AC output can be easily multiplied with a Cockcroft & Walton circuit.

4) An LOPT does not have enough energy to power a Tesla transformer, except perhaps a small one.

5) Yes, that circuit is well known to work and give good results.

6) No: the circuit given is intended for powering LOPTs. The easiest, most simple way for the beginner to power a tesla coil is by using an old fashioned neon sign transformer in a steel case (i.e. an "iron" transformer in a case about the size of two house bricks, and not the modern electronic NST, which looks like a long plastic block)

The essence of good science is not so much a memory for facts, (though this is more than useful!

) but a knowledge of how information is first to be had and obtained. In a word, "research skills."

While most of our members are proudly enthusiasts and hobbyists, we try at all times to follow the principles of 'good science,' which means that we expect that our members will have tried to find out as much as they can from Wikipedia, from Google, and from searching this site before raising an old question in a new thread - please do your own homework!

So welcome to 4HV.org!

Harry
Moderator

Heitor

Wed Oct 28 2009, 03:51PM

Registered Member #2449 Joined: Tue Oct 27 2009, 09:39PM
Location:
Posts: 2

Thanks for the answers and the welcoming to the forum!!!
And sorry for raising an old question... I didn't know...

Now I have another doubt:
Mads Barnkob said these circuits can power a Tesla Coil and Harry said they can't. oO
Can it???

Arcstarter

Wed Oct 28 2009, 05:11PM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Yes, they will power a Tesla coil. In fact, Harry did not doubt that it can at all. He did, however, state that it would be a small one.

An LOPT in normal conditions, inside a TV supplies what, maybe a few watts? I have pushed LOPTs to 700 watts, i have done short bursts of 1.4kw, and Firefox is apparently doing 1kw for quite awhile. It is fun stuff! But you must be careful pushing power like that. I had a flyback explode, on 720 watts. I here some cracking, then finally a large chunk blew off, and drew blood on my arm. It happened another time, and it shattered the ferrite core.

Also, in a Tesla coil, it would be subjected to HV kickback, from inductive field from the primary of the coil collapsing, and there is RF feedback, and all sorts of things. They will not live long. But, i have seen some meaty Tesla coil arcs from a few of the guys in here.

Do not give up hope on using these drivers for Tesla coils, though! They will work, and they could last awhile, too. Definitely not something to try yet, but in the future you could make your own high voltage transformer from an LOPT core... That is something for later, though.

uzzors2k

Wed Oct 28 2009, 05:28PM

Registered Member #95 Joined: Thu Feb 09 2006, 04:57PM
Location: Norway
Posts: 1308

The Mazzilli ZVS has been used for both SGTCs and SSTCs, so take your pick. Vasil's SSTC is the only one I can remember off the top of my head.

vasil

Wed Oct 28 2009, 08:15PM

Registered Member #229 Joined: Tue Feb 21 2006, 07:33PM
Location: Romania
Posts: 506

The ZVS can power a little SGTC for sure. Look here:

LINK

From "Step 6" to "Step 9" I developed a little tesla setup using a ZVS driver and a unmodified flyback. The setup is able to push single swirling streamers:

MOVIE

So, it can be done.

Even more, charging a 50-100 nF cap in a classical SGTC, with sufficient secondary inductance, give long sparks (up to 70-80 cm range), in single pulse mode (step 10 to step 14). So, a lot of fun. You can go with a small TC with high BPS to get little dancing streamers or with bigger setups to get single strong and noisy sparks.

Proud Mary

Fri Oct 30 2009, 01:05PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Thanks Arcs, for clarifying my position .:-)

As to Mr Heitor, it's probably fair to say that I am one of the more conservative thinkers at 4HV.org If the LOPT data sheet specifies an input of 90W for operation 24/7 than that is the advice I will give. (Almost all LOPTs now in production, or still current, fall in the range 90W - 110W. What could the EHT output of such a device be? 30W? 40W? Hence I have said it could power only a small Tesla Transformer. Others may get much more out of it, on the understanding that it will very likely be shortlived.

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob