Dr Ronald Stiffler SEC technology

[itsu]

Thanks for the suggestions guys,

the switching time of a 1N4148 and a BAT42 does not differ much (5ns), so need to find a faster diode for
to have any measurable difference i guess.


I did a quick time measurement of the current signal at both sides of the led entry, they differ 24.8ns.
So that implies that each diode add a time delay of 24.8 / 15 = 1.7ns, but this time delay does not build
up gradually, instead it kind of "jumps" from 0ns to 24.8ns after where the the L3 coil is positioned at the diode loop.

Itsu

Just to backup what i was saying above in bold with a video.

I taped all to my desk to get a stable setup and measured the input to the 12 leds with my yellow probe
which also serves as the trigger point.

The green trace is the current probe starting at the leds plus entry point, then going around to the minus entry
point.

The L3 coil has the diode loop top going inside it to avoid again movement.

I fixed the starting signal by making it Ref1 point, then move the current probe around the loop to watch
for any time delays around the diode loop.

No time delays are seen untill skipping across the L3 coil (which is on the top of the diode loop).
Right after the L3 coil there is a time delay of 25ns which again stays the same untill the current probe
reach the minus entry point of the leds, see screenshot. (yellow voltage / trigger point, white initial current signal,
green ending current signal)

So to me this means that the diodes do not introduce any time delay, its the L3 coil which injects the
signal in the loop that somehow produces this.

Video here:  https://www.youtube.com/watch?v=LAP9LgPWmfI

Sorry about the video, its kind of shaky.


Itsu   

[itsu]

Perhaps even more important than Vf is the switching time or reverse recovery time of the diode. The faster the diode the higher the operating frequency it can sustain, this is obvious, but what may be less obvious is that faster diodes will "capture" more of the peak of a waveform of even a lower frequency, thus resulting in a higher capacitor charge voltage. This is because the diode shuts off faster so doesn't allow as much reverse leakage out of the capacitor.

Another thing to try is to use a few LEDs in the loop instead of diodes all around. Use, say, three LEDs in series (to approximate the same total Vf of the full diode ring) and complete the ring with a simple wire, the same total length as the 1-LED, diodes all around, loop. A tiny little trimmer cap across the LEDs may help.

While waiting for some low Vf SMD diodes i tried TK's 3 led suggestion.
Each led has a Vf of about 2.7V, so 3 would almost cover the 15 x 0.6 = 9V drop of the 1N4148's.

Using my PS i see that it needs about 38V to light up the 12 Leds on the board plus the 3 leds in the ring.

We have about 15Vpp using my FG at 18Mhz when in resonance which is not enough to light them.
Even the 3 trimmer cap (0 - 100pF) across each of the 3 leds can not improve much (1st trimmer left has
no effect at all, middle / top trimmer some and the right trimmer most), see screenshot where the yellow
signal is across the leds on the board.

Itsu

[Lidmotor]

Erfandl---  Thanks for the tip about the inductor on your crystal oscillator.  I will try the barrel types and see what happens.  I also will place the components on the board exactly like have them placed.  At this MHz frequency the interaction of the parts in that tiny space may have an effect.

Itsu-- I was afraid that you might find that the 'time delay' explanation might not be the simple answer to the 'Loop'.  I guess we have to wait for Doc's further explanation of what is happening---and then test for that.   

All---This 'Loop' works great on a Slayer Exciter.   To me it just an AV plug on steroids.

---Lidmotor

[itsu]

In this video Dr. Stiffler introduces a shorted turn (with 1 diode) being placed across the
diode ring which makes the leds go of:  https://www.youtube.com/watch?v=qtNSko30ZMs&t=3s


I did a replication of this, monitoring the input into the L3 coil (voltage, current and power).
It seems that placing this shorted turn will detune the L3 coil out of series resonance causing the leds to go off.

No matter which way i place the shorted turn, the L3 coil is evenly detuned.

I can retune for resonance again when the shorted turn is in place, which will be lower in freqeuncy and lower  in amplitude.

Video here:   https://www.youtube.com/watch?v=bteRDsRfYmE&feature=youtu.be

Itsu

[gyulasun]

Perhaps even more important than Vf is the switching time or reverse recovery time of the diode. The faster the diode the higher the operating frequency it can sustain, this is obvious, but what may be less obvious is that faster diodes will "capture" more of the peak of a waveform of even a lower frequency, thus resulting in a higher capacitor charge voltage. This is because the diode shuts off faster so doesn't allow as much reverse leakage out of the capacitor.

Another thing to try is to use a few LEDs in the loop instead of diodes all around. Use, say, three LEDs in series (to approximate the same total Vf of the full diode ring) and complete the ring with a simple wire, the same total length as the 1-LED, diodes all around, loop. A tiny little trimmer cap across the LEDs may help.

Hi TinselKoala,
I wonder if the diodes in the loop switch on all at once or in groups or individually, what do you think.  If I understand you correctly, in your above post you suggest the diodes work about all at once.  This then may also imply that the best position of the loop is when the end part of coil L3 (where the near or close field) is the highest is in the loop center point.  Is this correct?

Gyula