Selfrunning cold electricity circuit from Dr.Stiffler

[DrStiffler]

One word of advice,   watch out how much power you put out in the radio spectrum.   The FCC will come knocking on the door, maybe even the FAA if you're close to an airport, or if you're in another country then the US, your local authorities perhaps.

Better yet, if you have a Spectrum Analyzer, you can try a rough measurement of radiated power, like they do officially in EMI labs (3 meter radiated emissions tests etc..) to see if you have energy above the CISPR specifications for radiated emissions.

One last note,  when you drive with a single transistor a multi-mode capable resonator, like you're doing in this case,  the modes of resonance can change abruptly.   My mini-Tesla does the same , but it's way more stable since I'm driving it with the separate Colpitts oscillator (which has it's own frequency), but still, if I get my hand near the main resonator coil, I can "snap" the resonance from one mode to another, which is interesting.  Mode locking certainly happens quite easily even with the Colpitts arrangement.  These modes and the interactions they have with the circuitry is not to terribly hard to understand, but it can be mystifying at times. 

My goal is to create as stable a resonator as I can.  I'm contemplating a crystal oscillator to keep it on frequency.

EM

@Emdevices
Thanks for the heads up, they might take my Federal License away from me and strip me of my Ham ticket 

If anyone is silently building Stiffler Oscillators with VLT's, you need some complex tools for probing them. Included are three pics of very complex probes that work great for finding hot spots and null nodes. High current White LED, 1N4148's on 1cc plunger.

[starcruiser]

that is sure hi tech Ron! 

As I always say KISS

[Loki67671]

@All & @ Loki

Loki, sometimes a person wonders why they take such care. In you case your followed you own knowledge sprinkled with a bit of input from me and build a real nice 'Thing', all in the hope of greater control and ease in measurement and not wanting to fight the stray artifacts that exist. What I mean is my information to you was based on all the smaller circuits (coil arrangements). Until I saw your VLT I wondered if it would work at all, so I built one, now many. In short you want to include the ability to move that inner coil and observe the Spectrum while doing it. There is a sweet spot where it goes 'WILD' as shown on some of my images. I know what you mean but haven't sustained it yet!

Second I am bothered by you low currents (like none), this indicates you are not at peak tuning yet. The only times I have seem no current is at lower voltages, and at the same time the supply voltage goes up (go figure  . I'm beyond doubting the panel meters and will be measuring current via ground leg shunt. I will have accurate measurements shortly. I cannot believe this circuit draws no current! But also I was taught to do things like take a few turns off the tank coil so the oscillator adjustment peak drops off more in the center of the adjustment range of the tank resonance. Yes I want to explore more range of adjustment, just slowly LOL 

I know you have not done it yet and will, but it is so insightful to also watch the spectrum while varying the supply voltage. Linear increase in V-supply is a standard test from the cookbook Sir! I use it regularly along with fast and slow rise transient to monitor for circuit instability. The SEC shows a very interesting changing spectrum based on V-IN from 0 VDC to 21.5 VDC in just the manual linear increase test, thats all I've done so far. At the shop I would have used a programmable supply. Like where you see the stair steps in the tuning, you will observe rather pronounced Power steps from one voltage to the next, (far from any linear curve) more like log.

And yes that pipe organ is not far off 

Just thinking out loud, with a Near Field of 1/3 wavelength in diameter and power dropping inversely with distance, yet this thing near field don't drop, where to put all the stuff is an interesting problem. Oh I certainly agree with that one, I made a picture in the spectrum analyzer display with my coffee mug this morning. 

@ Dr. Stiffler,
Added directly to quoted text above.

Jim

[Loki67671]

@All,
Made some measurements, applied some tweaks, starting to make a little more light. I completed the killer decoupling filter board today along with a change in the base coil and capacitance. I think I still need to make some observations and measurements to coax out the circuits max performance but I have seen very good improvement today. Specifically because I can now make accurate measurements, although I have not yet put together appropriate probes for looking at the waveforms, you can bet I'm gonna,,,  I added a decoupling cap from the inductor / emitter ground node to V+ for good measure and at the Doc's advice. :  I spose I'll light show it with LED's for folks but I think it's wasting valuable and fleeting labtime. Had some folks scratching heads today, har, along with me of course. I'm certainly trying to figure out what it's doing! Here's some old digital photo's of progress.

Best regards,

JIM

[Loki67671]

And todays light show was performed by, a real nice probe design by Doc Stiffler. Worked like a charm for performing the light show, but more importantly is the ability to explore the entire circuit for illumination of the LED. It is a fascinating search. More LED's to follow. 

Best regards,

JIM