The Old Standard Ignition System. Battery. Coil. Points. And Condenser....

[tinman]

Ok. I get what your thinking, that the loading helps to slow down the field collapse for the time period thus a longer spark. Is that correct?  Well then why would that not happen also without the cap?  We get sparks when we release the battery current from the primary after the field build without the cap, so why isnt it a slowed collapse and long burn then, without the cap in place?  Doesnt wash.

Mags

Because without the condenser,most of the stored energy is dissipated through the arc at the points.

If you replace the points with a FET or transistor,then you will not need the condenser to achieve the same spark burn value.

The length of the spark burn time can be increased by decreasing the spark plug gap,or decreased by increasing the spark plug gap.

It would also be nice to know what the V/PD on those scope shots are--why is there 0 volts across the coil primary when the points are closed?,when it should show supply voltage.

Then there is the question-->do things change when the spark plug(and thus the spark) is subject to the high pressures and gas mixture of the cylinder ?.


Brad

[Magluvin]

Because without the condenser,most of the stored energy is dissipated through the arc at the points.

If you replace the points with a FET or transistor,then you will not need the condenser to achieve the same spark burn value.

The length of the spark burn time can be increased by decreasing the spark plug gap,or decreased by increasing the spark plug gap.

It would also be nice to know what the V/PD on those scope shots are--why is there 0 volts across the coil primary when the points are closed?,when it should show supply voltage.

Then there is the question-->do things change when the spark plug(and thus the spark) is subject to the high pressures and gas mixture of the cylinder ?.


Brad

I could change the voltage division to see the switching, but Im on the 50v scale as it is. My scope freaked out on one of my previous vids due to over voltage spikes. I hear a relay click in the scope when I go below The scope says max 300v and its over shooting the screen saying upper 450s with the 10k series with 10k resistor voltage divider this time around.

I just picked the largest inductor I have for this, so things might be better or worse with a different inductor value.  But I believe it was a decent demo of the 2 circuits, in my opinion anyway. It helps prove the resonance helps produce a muti spark.  The longer the spark the less multi sparking happens as I believe the ring down cant handle the distance after the first spark discharge at that gap length in the last vid.

Mags

Mags

Mags

[Magluvin]

Came up with a test.. 

Lets see what the primary freq with the cap is when I dont let the spark happen.    The primary is 5.79mh when the sec is open and .9mh when the sec is shorted. Work in the value of the spark resistance and it shows 12.khz on the scope and I calculated 14.17kz (That is the correct freq calculated not he arbitrary 15 I used earlier) with the sec shorted.  So with the sec open, the primary measures 5.79mh and the calculated freq is 5.59khz.  If i make the spark gap unbreakable(to the max air distance) then the primary ring should be closer to 5.59kz than it would be 12khz as seen when the spark is allowed to occur.

This would further prove resonance that we can approximately calculate to be true. Approximately means things affect the outcome like the resistance of the spark changes how heavy the load is on the secondary in order to affect the primary inductance. We do not know the resistance of the spark yet. So shorted sec its 14.17khz and with the spark resistance can change the load and probably give us the 12khz result on the scope. So this should make it a hard argument to say the resonance has nothing to do with anything in the operation of the circuit, let alone deny it even exists or that the secondary doesnt react to the primary induction. lol

Gotta post as is. Im beat. Up all night doing this project. Ill fix things i didnt see now tomorrow.

Mags

[citfta]

Well, I am about to open a whole can of worms here but I think this needs to be posted.  Technically speaking resonance is not what we are seeing here.  If you look up the term resonance, it is described as a device or circuit that responds to an applied signal or impulse with a positive reaction.

Think of two tuning forks that are both tuned to the same frequency.  When you strike the one and set it to vibrating the other one will also start vibrating.  Of if you tune your radio to a certain frequency it is in resonance with the transmitted signal.  Ham radio operators tune their antennas to be resonant to the applied transmitter signal to make the antennas more efficient.

So what is the proper term for what we are looking at?  I believe we should be calling this ringing at a certain frequency just simple oscillations, not resonance.  There is only one device involved.  There is no second device that is resonant with this device.  This is being kind of nit picky but technically correct.

My problem with MH's posts is that first he insisted there were no oscillations or ringing and then after he posted videos that clearly showed there were, he still denied they were playing a part in the increase in spark over a circuit with no cap.

I do agree the primary is strongly affected by whether there is or is not a spark being produced by the secondary.  This is just the simple action of any transformer that reacts to the change in impedance caused by loading the secondary.

Now Mags other thread about acoustic and other forms of resonance is correctly about resonance.  As I posted in that thread I have even built devices that clearly responded to certain audio frequencies while rejecting other audio frequencies.  Those devices show what resonance really is.

I still stand by my original post about how the ignition circuit works.  The only thing I would add is what has been pointed out by some is that yes the oscillating frequency of the primary is affected by whether there is a spark or not.

Respectfully,
Carroll

[Magluvin]

Sorry Cifta.  But if you search LC resonance, this is exactly what this ringing is, resonance.

If you run your wet finger over the top of a crystal wine glass, the tone you hear is due to resonance.

Tap a bell and the tone you hear is due to resonance.

There is no requirement for a resonant receiver in order for it to be called resonance.

Now, do a search on LC resonance.  Do a search just as i have posted here the other day on LCR resonance.

Now refine that search to resonance LC and look for images like the pics in the search below

Then tell me why I cannot call it resonance.

mags