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https://web.archive.org/web/20170203092 ... te1425.pdfexhaustgases wrote: ... It does seem counter intuitive that closer molecules would offer more resistance.
Low pressure spark plug testers are commercially available, but proper testers use higher pressures and a modern relevant ignition system, ideally a high powered racing engine ignition system.exhaustgases wrote: ↑Sat Apr 14, 2018 4:33 pmYou can still get spark plug testers, I've used them in the past as well. It does seem counter intuitive that closer molecules would offer more resistance.Kevin Johnson wrote: ↑Sat Apr 14, 2018 8:33 amhttp://www.mtfca.com/cgi-bin/discus/board-profile.cgi?action=view_profile&profile=ndnchf-users wrote:Back in the day, Champion made a plug tester that has a pressurized chamber for testing plugs. It has a model T coil inside and connects to an air compressor. I have one and it works great. I set the pressure at around 55 lbs to test T plugs. The difference in spark is eye opening.
Champion 1.gifChampion 2.gif
The number of electrons in the outer shell of the atom makes all the difference.exhaustgases wrote: ↑Sun Apr 15, 2018 6:57 pmHow about with metals? They are closer yet.
Now it would be interesting to know how it affects chemical reactions, combustion.
exhaustgases wrote: ↑Sun Apr 15, 2018 6:57 pm
How about with metals? They are closer yet.
Now it would be interesting to know how it affects chemical reactions, combustion.
The term dielectric strength May be more fitting description approx 20kv/cm.exhaustgases wrote: ↑Mon Apr 16, 2018 2:53 amSo what is that comment for? I'm 11 almost times 6 and know well about valence electrons. Just trying to make an interesting discussion.joe 90 wrote: ↑Mon Apr 16, 2018 2:13 amexhaustgases wrote: ↑Sun Apr 15, 2018 6:57 pm
How about with metals? They are closer yet.
Now it would be interesting to know how it affects chemical reactions, combustion.
You learn that at school, or at least we did way back as 11 year olds. But probably not these days.
When I was a kid climbing towers I didn't have enough sense not to I could feel the affects of the electrical discharge on a 90 degree dry summer day on my arms/ hair etc. There was no arcing to me if there would have been I'd not be here now. Just saying.......
And from Kevins info.
As mentioned earlier [6, 14], nitrogen is an ideal gas
to use: it is abundant, cheap, inert, non-toxic, nonflammable,
and unquestionably environmentally
acceptable.
However, nitrogen is a non-electronegative gas (it
does not attach electrons) and for this reason its dielectric
strength is rather low. Nitrogen, however, is a strong
electron-slowing down gas and this property accounts for
its relatively good dielectric properties in non-uniform
fields and in the presence of conducting particles, and for
its excellent performance in mixtures with electronegative
And for airs resistance found this.
Its resistivity is approx. 2x10^16 ohm-meter
Geoff2 wrote: ↑Sat Apr 14, 2018 6:05 am Also, the resistance of the leads is in series with the resistor [ if used ] in the spark plug & this combined resistance, which is also in series with the air gap, is only a fraction of the resistance across the air gap of the plug electrodes. So the resistance of the plug lead + plug resistor has negligible effect on the required voltage to ionise the gap in preparation for spark current to flow. Once current flows across the gap & voltage drops to ~1000-1100v, THEN the circuit resistance has a significant impact [ reduces current ].
Air doesn't have resistance nor resistivity as such.exhaustgases wrote: ↑Mon Apr 16, 2018 2:53 am
And for airs resistance found this.
Its resistivity is approx. 2x10^16 ohm-meter
I learned something new today. Thanks.Fred Winterburn wrote: ↑Fri Apr 20, 2018 5:12 pm There is always a significant voltage overshoot prior to the spark occurring beyond the actual voltage requirement for the spark itself.
What is the procedure employed to accomplish this comparison testing ? Is 100 MHz fast enough or how fast a scope is required?Fred Winterburn wrote:despite the fact the variation in voltage overshoot is easily measurable with the right equipment. You will not see this on an oscilloscope without comparison testing, which is why, I believe, this is not a better known phenomenon. Fred Winterburn
That's due to the capacitance, resistance and inductance of the HT leads.Fred Winterburn wrote: ↑Fri Apr 20, 2018 5:12 pm There is always a significant voltage overshoot prior to the spark occurring beyond the actual voltage requirement for the spark itself.
Reducing current flow does not require resistance.
No idea.lvecch wrote: ↑Wed Apr 20, 2022 4:44 pm But I have made some tests and I observed that is not only the amount of resistance what is needed, but it has to be distributed along the path. For example, I observed if I put a 15Kohms spark plug wire cobined with a 3.5ohms spark plug, it works well, but if I put a 20Kohms wire and a non resitor spark plug, it affect the engine controller. I do not understad why. Is seems that it can´t be a piece of conductor longer than x without a resistor, otherwise it increase the emission. I am an electronic engineer and the only idea that could come to my mind is some kind of stationary waves produced on the non resistive conductor longer that some amount. Could somebody guess about it?