Physics Honors Project Questions

[rough_wood]

We have an honors project to make a spark gap. We bought an ignition coil to accomplish this. We currently do not have enough knowns to solve for all the variables involved (we think).

We are using a 555 to send a changing current to the ignition coil. We have the ability to measure its frequency. 12 Volts (square wave) are being sent through the transistor to the 2 screws of the Ignition Coil.

Using an Extech LCR, we got about 6mH off the screws, and for one end on a screw and the other on the spark plug wire we got 5.644H@120Hz 59.7H@1KHz.

We know the input EMF is 12V (2 lantern batterys) and the output EMF is 30,000V. The resistance from one screw to the spark plug wire was 12.9Kohm@120Hz and 53.75Kohm@1Khz. The resistance between the screws is 1.59ohm.

We are having troulbe because we can't find the number of turns, or the length of the wire in the Ignition coil. We are trying to solve for these, but we don't know dI/dt since the current isn't a square wave like we send. We don't have equiptment to measure dPHI(Magnetic Flux)/dt directly.

We do have an equation I=(EMF/R)(1-e^(-t/(L/R))) but we never covered that section of the book. Maybe the t is the time of the top of the square wave is when voltage is on but again, we weren't taught this section.

The longest spark we have gotten was about .4", generally it's around .25".

Any advice? Maybe there is an equation we are missing, maybe someone knows the internal workings of of Duralast C819 Ignition Coil (number of turns, etc), how to get mutual inductance from the values I mentioned above, or any other solveable variable we aren't aware of.

We appreciate any help. We are studying for finals and scurrying to finish this and a couple other honors projects.

On a side note, this is my first post here. I have everything I need to build my first Bedini this summer (after finals).

[rough_wood]

Am I getting a cold shoulder because I broke some rule I don't know about or do you guys not know?

[Aaron]

coil specs

Hey Rough Wood, I just saw this myself.

Have you used some AWG calculators to enter the resistance (I'd check it with everything off first) - and start entering small gauges of wire to see what the length is.

When you get a length/gauge that would roughly fit your geometry of coil case, you'll have a good idea of the length. Unless you know exactly from the manufacturer, that might be a way to go.

Someone else here probably knows better. This cinco de mayo so maybe everyone is out partying

[ren]

Hi Rough Wood,

Check out these threads.

"Gray Tube Replication"

and

"Imhoteps Radiant Oscillator"

Both threads involve HV, usually derived from an ignition coil or similar HV transformer. Both threads have schematics of various levels of difficulty.

Ignition coils are usually a 1 :100 ratio of primary to secondary windings, or even more. Pulling one apart to count the windings however isnt really an option. They are usually encased in epoxy or oil and the removing of is a significant task.


For increasing spark distance please note other variables which may have not been considered. Discharge terminals and moisture/wind in the vicinity are two I can think of off the top of my head.

[Inquorate]

555 timer

if you guys are just starting out on this stuff, try using a self oscillating relay instead of 555 timer. but if you do use a 555 timer, you'll want to hide it behing diodes, transistors or relays, else it will get fried.

and the threads ren mentioned are a goldmine for creating sparks.

love and light

[wrtner]

A couple of directions to look in

We have an honors project to make a spark gap. We bought an ignition coil to accomplish this. We currently do not have enough knowns to solve for all the variables involved (we think).

You could look at Chapter 5 of this book:
Free-Energy Devices, zero-point energy, and water as fuel
or check out some of these ideas
Spark Gap Experiments
and then come back to us with what you have selected.
Paul.