ENERGY AMPLIFICATION

[TinselKoala]

Forest, if you can, please try to display only two full cycles of the waveform, and let's see if your scope resolves the fast rise of the spike.
Next, you can expand the time scale even more, to zero in on just the spike portion of a single cycle, to see if the scope can make a visible trace as the signal voltage shoots up (or down).
You are missing a lot of detail of your circuit's performance hidden in the spikes, where your scope just shows a blank discontinuity right now.

You can estimate the length of wire in the sealed coil in a couple of ways. First you can measure accurately the coil's DC resistance and compute the length of winding wire from that---if you can get an accurate and precise resistance measurement.
Or, if you have a good signal generator, you can sweep the coil's primary and monitor the voltage on the secondary, looking for a resonant peak. The biggest resonant voltage rise will occur at a wavelength 4 times the length of the coil's winding, adjusted somewhat for the core of the coil. So the wire length will be roughly 1/4 the wavelength of the frequency that excites the largest resonant voltage rise in the secondary.

Why do you need to know the length anyway? To find the resonances empirically is always easier for me...my calculations are usually wrong anyway.

[forest]

Thanks TinselKoala

Precisely I'd like to find 1/4 wavelength for this coil ;-)
but I have only impulse square wave generator 1Hz-10Mhz and do not know wire diameter inside coil.
How can I find where voltage on output is maximum ? Cannot use scope because it will burn it from HV
My scope is very old and I have no experience,I haven't found a way to scope only two full cycles of waveform, there is only a way to trigger once (instead of automatic)  but I've never make it to work for me - in theory what it should show me ?
I'm trying to use ordinary parts to make Tesla coil with all Tesla comments in my mind.
Another question is how to shift phase of input oscillator according to the +DC sinus of RLC circuit so it will break it exactly at the peak of RLC wave ? Can scope properly display phase relations between two channels inputs in chopper mode ?

[Magluvin]

Hey Forest

What he is saying is, you can use the signal gen to apply a signal, and the scope, to find that freq, and from that you can determine the length of the sec.   

But I think I know what your concerns are with hv.     I believe he is saying to just apply the sig to the sec, not the primary, to test the sec for 1/4 wave freq.  I cannot say for sure that if you did hook up the sig gen at very low input to the primary, that the sec may still output hv.  But probably.  If 12v can produce 15 to 20 kv   then 1v in can produce 1 to 2kv.  Even at very low input current, at certain freq.

I would say to just apply the sig gen to the sec, and measure across that with the scope, then sweep.  You will see that some freq will provide high points and low.  As TK says,  the highest point will be your target freq, and then calculate for length.  =]

I have seen diagrams of the internals shown as the common end of the sec connected to the + of the primary, and others show the common of the sec to the neg of the pri.    I have tried to measure the coil that I have with my meter to determine which, and my wavetek  is accurate to .01 ohm, but the sec resistance is to high, and the difference in adding the primary in series, I cannot tell for sure on my coil.   

I would try both + and - for the sec test to note a difference if any.  =]


Mags

[gyulasun]

Hi forest,

You could make a coupling coil with a few turns (say 5-10 turns only, self supporting 1mm dia enameled copper wire, coil OD say 2cm) and connect to this coil your scope probe.  Then place this coupling coil near to the top end of you HV coil say a few cm away and start sweeping from the very low frequencies, gradually up and up till you get the first big voltage maximum on the scope, then continue exploring the higher frequencies where else may give newer big amplitudes etc. 
This way your detuning effect is the smallest possible and when you find a big voltage maximum try to reposition your coil probe further away to further reduce any loading on the HV coil due to em coupling and always  RETUNE finely your generator if the repositioning may have caused some detuning.  This is a tiresome and time robbing procedure for sure.

rgds, Gyula

[TEKTRON]

Something I thought of that doesnt make sense to me.

Considering a transformer, lets say step down,  say 10 to 1,  with 100v in and 10v out.
If ya think about it, on the secondary, the voltage is stepped down, less motive force, less pressure, yet the amperage capability is relatively high.  Or the other way around, 100v, high pressure, but low current content.  Sounds like something is wrong here.  I just really never looked at it that way before. Sounds like basic info, but when we consider the pressure(voltage) capabilities in each situation, something doesnt seem right.

Is it only related to the AWG size of the wire for the pri and sec? 

If we looked at a step up as if it were gears and the teeth were turns, The sec, larger gear with more teeth, has more pressure, force, voltage, and low current, low current as in the gear moves slow, things are moving slow on that side, where as the smaller gear, the primary, can be driven with little pressure, voltage, but great amount of movement, current.

I dunno.   It seems as if there were a way to make a transformer that had gain, we may be able to apply that idea to gears in some fashion.   weird

I just have these crazy visions of it has to be done another way.   Its like havin a name you cant recall on the tip of your tongue.   

Mags

Mags, Agent Gates thread was topic 8586.
I'm new to the boards and electronics. Ive been playing the SIM and screwed around with the transformer specs. I really feel that you can NOT trust the results at all. Unless I accidentally fell into a perfectly tuned OVER UNITY circuit. ~500x unity!!! 2w in 1kw out. What do Ya'll think???