If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
This is a very simple and reliable circuit and can be built including the flyback inside a small box. The heart of the circuit is a TRIAC device, basically two antiparallel SCR's. It does not need a heatsink. The circuit works by discharging a small capacitor through the flyback primary in each mains halfwave, producing a high voltage pulse on the secondary winding. The output spark produces a characteristic crackle at mains frequency, which adds to the "coolness factor". With more primary turns and bigger capacitor (labeled "C" in the schematic), the produced spark will be much hotter and can be used to drive e.g. a small Jacob's ladder. This circuit stresses insulation in the flyback's secondary, and breakdown can occur at lower voltages than with high-frequency drivers, but the breakdown is not usually fatal for the flyback because there is not enough energy in the spark to actually damage the insulation.
In my setup I used two seriesed secondaries on one core. The output spark can reach about 4cm. After it's tuned I will built it inside a small box (for "high voltage demos" )
sorry, I couldn't get better picture of the sparks
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
I like this circuit because of its simplicity and because heating of the components is next to none. I was able to get about 6cm spark from my duo-flyback, but I had sparking between one of the secondaries and core, so in final version I will pot the whole thing in wax (from some old candles) for better insulation. So far I haven't found a way how to regulate power down to zero (or near-zero), if anyone has an idea, it would be great!
Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
Down to zero? Okay, just rearrange your pot as a divider network and it should go to zero. Try the legs of the pot across your 22nF cap, and the wiper going to your 220K feed resistor. I should also mention that the 1M in || with the 22nF will probably change your RC time, so you might want to reduce the 22nF to 10nF or less, but give that a shot.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
Hazmatt_(The Underdog) wrote ...
Down to zero? Okay, just rearrange your pot as a divider network and it should go to zero. Try the legs of the pot across your 22nF cap, and the wiper going to your 220K feed resistor. I should also mention that the 1M in || with the 22nF will probably change your RC time, so you might want to reduce the 22nF to 10nF or less, but give that a shot.
hmm... thanks, I tried that, when I turn the pot from one side, the output voltage increases until at one point abruptly turns off. Maybe I should refine my question as, is it possible to control the output *voltage* from zero (or near-zero) to full (this means either from 0 to 90 or from 90 to 180 degrees)? There is a problem that when the triac fires, the kickback from the primary turns it off, so it is possible for it to fire multiple times in each halfwave, and this also results in that it fires quite irregularly.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
TRIAC Flyback Driver
)
