# Simple electric arc, spark gap.

Discussion in 'Electrical Forum discussion & Blog' started by kharris485, Jan 2, 2011.

1. ### kharris485New Member

Joined:
Jan 2, 2011
Location:
San Francisco, Ca.
I am making a piece of art. The piece requires a simple electric arc, before I go spending a lot of time experimenting with different transformers and capacitors I was thinking that maybe someone already had a valued diagram of this project. Remember just a simple arc. I understand the spark gap will have to be really close because I'm only using a 9volt battery. I'd like to get the voltage up to about 500,000 volts to insure a good spark. The stream would be activated by a switch. The entire workings will be encased in a plexiglass box. The works are much like a stungun. Please don't respond with complicated Tesla coils, etc. Remember simple arc, gapped, two electrodes. KISS.

2. ### jwelectricElectrical Contractor/Instructor

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Instructor
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North Carolina
You have already kept it fairly simple, its called a tesla coil

4. ### kharris485New Member

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Jan 2, 2011
Location:
San Francisco, Ca.
Still need capacitor and inductor values for the circuit. If anyone out there has made electricity jump a gap between two points with a 9v battery, would appreciate a diagram with values for resistance, transformer, and capacitors.

5. ### jwelectricElectrical Contractor/Instructor

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Try doing a google of tesla and all kinds of sites will open up with kits, diagrams and the such. This would be a lot easier than trying to post one here.

6. ### nukemanNuclear Engineer

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Nuclear Engineer
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VA
There are a few simple ways to create a spark, but the 9v battery requirement is going to be a big limitation.

1. The voltage is low, so limted on what you can drive with it,
2. The capacity is low. If you want more than a couple sparks, you'll need something else.
3. The voltage is DC. This reduces your options.

500kV will also be difficult. Possible (especially if AC power available), but you have fewer options at this level. If you target more like 30-50kV, there are more options.

Some other possibilities:
- circuit with TV flyback transformer
- automotive coil (12v (or 9v) to coil (+), coil (-) thru pushbutton switch (normally open) to ground)..will spark each time the button is pushed (actually on the release of the button). You'll probably need a resistor in the circuit since the coil current shoots up when it saturates. Electronic ignition modules in cars have built in current limitation to help with this (usually ~7A).
- automotive coil + igniter (such as GM HEI module). Add simple circuit (555 timer IC) to send pulses to igniter to fire the coil at some certain frequency
- van de Graaff generator (motor + belt)...works on static electricity
- magneto based ignition (lawnmower, weedeater, etc.). Spin magentic flywheel past pickup to induce the spark.

The automotive coil will probably be the easiest (and cheapest) to do, but you won't get 500kV out of it (more like 30kV for a stock coil and ~50kV or so for aftermarket)

How large of a gap do you need to jump? Is it possible to use a different power source? How many sparks do you need per charge (assuming your are stuck with a battery)?

7. ### jimboPlumber

Joined:
Aug 31, 2004
Location:
San Diego, CA
What abot a push button barbecue sparker? If if needs to spark repeatedly, incorporate a monkey , or a simple motorized lever, into the art work

8. ### jwelectricElectrical Contractor/Instructor

Joined:
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Occupation:
Instructor
Location:
North Carolina
I have posted a new sticky at the top of this forum. No matter which route you choose please know that charged capacitors can deliver large amounts of current so please read the sticky before attempting to build a sparkle.

9. ### ballvalveGeneral Engineering Contractor

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Dec 28, 2009
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"retired" and still building and troubleshooting
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northfork, california
Your stickie would be useful to the DIY who is mostly reading here and prone to errors if it incorporated some concepts he could latch onto.

The guy trying to change a light switch doesnt know a milliamp from a kilowatt from a gigawatt.

10. ### Ian GillsSenior Robin Hood Guy

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Jul 24, 2007
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Robber, with some DIY on the side.
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USA
I got a nasty shock from a capacitor in a disconnected ceiling fan once. That really hurt.

11. ### kharris485New Member

Joined:
Jan 2, 2011
Location:
San Francisco, Ca.
Thanks, was very helpful, I think I might try 120VAC instead of 9V battery. The gap could be very very close (like 1-2mm). Just needs to light up when someone pushes the button. Doesn't need to stay on for long either, that's why I was thinking battery. Interactive art piece.

12. ### jadnashuaRetired Defense Industry Engineer xxx

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Sep 2, 2004
Occupation:
Retired Systems engineer for defense industry.
Location:
New England
A simple barbeque igniter might work for you and runs off (typically) one AA battery. To let it work longer, you could put multiple ones in parrallel. When you start to get into line voltage, you start to have much greater liability issues with safety.