Flyback Question / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

Flyback Question

previous 1 2 3 next

Move Thread

LAN_403

Josh

Wed Jun 02 2010, 05:01AM

Registered Member #938 Joined: Sat Aug 04 2007, 05:39AM
Location: Honokaa,HI,USA
Posts: 65

Thanks for the information.,
I think i could salvage a PSU from an old computer.
I'll search 2n3055 for the heck of it and to learn something new :)
So what(I am not semiconductor knowledgeable enough to compare specifications and tolerances) FET would you recommend?

Steve Conner

Wed Jun 02 2010, 09:27AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Some small, low-wattage light bulbs don't have any gas fill, they're evacuated. Oven lamps and so on. These are the ones you need to watch out for.

If you're zapping one of these with a Tesla coil, and you see the glass glowing green or yellow, it's time to reach for the lead underpants.

Josh

Wed Jun 02 2010, 07:05PM

Registered Member #938 Joined: Sat Aug 04 2007, 05:39AM
Location: Honokaa,HI,USA
Posts: 65

Hmm.
I'll go with a large light bulb and watch it.
Radiation isn't something I'd like to encounter unless
I am wanting to intentionally producing it and have "everything" I need to contain it effectively.

Matt Edwards

Thu Jun 03 2010, 01:54AM

Registered Member #2838 Joined: Fri Apr 30 2010, 07:55PM
Location: tehachapi, CA
Posts: 333

I was playing with my tesla and a 40w appliance bulb for a bit (unknowingly), and when I went to turn on my ceiling fan lights (fluorescent) they started to flicker every time I placed my hand near them. I guess that I had reached my body's capacitance level.?. Anyway, here is a photograph of the bulb lit by the tesla. The arc that you see on the left is going to my finger.

Josh

Thu Jun 03 2010, 04:56AM

Registered Member #938 Joined: Sat Aug 04 2007, 05:39AM
Location: Honokaa,HI,USA
Posts: 65

Is the skin effect null and non applicable when your taking power from a tesla coil because your skin isn't very thick nor conductive?
In other words isn't it a bad idea to let a tesla coil shock you,
I know you can't feel it but isn't it damaging?

Myke

Thu Jun 03 2010, 05:35AM

Registered Member #540 Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969

I am unsure of whether HF AC will affect you even though you can't feel it. Most people don't like to touch the output streamers of their TC because it usually burns little holes in the skin. This is from the high temperature of the plasma in the arc. RF burns are pretty nasty since it makes the wonderful(sarcasm) smell of burning flesh and the burns take quite a while to heal.

Proud Mary

Thu Jun 03 2010, 09:13AM

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

Myke wrote ...

I am unsure of whether HF AC will affect you even though you can't feel it.

RF burns can and do put smoking holes in skin and bone - think of ohmic electrosurgery with its "RF knives," and the dielectic heating principle of diathermy units - two different ways of cooking your goose!

Josh

Fri Jun 04 2010, 06:09AM

Registered Member #938 Joined: Sat Aug 04 2007, 05:39AM
Location: Honokaa,HI,USA
Posts: 65

Yeah I remember when I had the driver(actually a $60 or so kit from Rasmey electronics)
you could on a humid day draw an arc to a firework fuse and light it.
Plus burn random stuff.....

I am going to do this circuit I think,
should be better than the classic 2n3055 circuit...

By the way how much UV could you get from a flyback?

I have a good chance of getting a paper signed so I can drive because my vision is not that great...
Anyways I really value my vision and don't want to expose my eyes to UV that would exeed a sunny day, hawaii has enough of it already.....
Some(ones that say so) polycarbonate safety glasses should filter out low amount of UV I believe.
I know spark gaps can do tons of UV,
but I have no clue about flybacks.
Sorry for all the questions...

wylie

Fri Jun 04 2010, 07:53AM

Registered Member #882 Joined: Sat Jul 07 2007, 04:32AM
Location:
Posts: 103

By the way how much UV could you get from a flyback?

It all depends on what you're ionizing/vaporizing with the arc. If you value your sight, you shouldn't be looking at ANY arc directly for any duration of time (of course, it's also not advisable to be working a chickenstick with your eyes closed lol). Visible and Infrared light can ruin your sight just as well as UV. Welding masks for the win, though its tough to get the arc started when you can't see anything...my buddy gave me one of the flip-variety, so as soon as i strike an arc I flip the mask down.

The circuit you linked: there's plenty of comments that say it won't work if you don't have "The Right Transistor." The easiest, Sure-Fire method, IMO (and mentioned in that thread as well) is to run a 555 oscillator into a decent FET. I used IRF510s from radioshack. They work at 12v well enough, and CAN be driven right from the 555 (though a buffer might be desirable). You wont get crazy power from them, but they work, and don't explode...with the 12v supply. I blew one up when i tried a 20V supply, but with no measurements going at the time I have no idea why. Never bothered to try it again. The IRF840s i pulled out of some PSU's worked even better, but i burned them out by neglecting their total-dissipation ratings

RF burns can cause gangrene. Don't touch electricity, even when it doesn't hurt. Well, VanDeGraffs are okay, but damn, mine wasn't even that good and it HURT!

Matt Edwards

Fri Jun 04 2010, 07:31PM

Registered Member #2838 Joined: Fri Apr 30 2010, 07:55PM
Location: tehachapi, CA
Posts: 333

I still recommend the mazilli driver circuit! It is easy to setup and it produces vary good results. But if you over power it it will definately kill your flyback.

previous 1 2 3 next

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