COP 17 Heater | Rosemary Ainslie

[Groundloop]

Harvey,

I will set up the test again and run sweeps up to 1,3GHz. That is the
maximum frequency scan I can do. Is this high enough? But it will take
some time because I can only cover approx. 50MHz at each sweep,
and I must do each sweep twice to know the background first. But it
have to wait for the weekend, because I busy right now.

Groundloop.

[Harvey]

Hi Groundloop,

It is more of a curiosity for me just to see how wide the range is and where the dips are. To me, the dips indicate the best area of low loss operation. But the rising dBm as the frequency climbs makes me wonder if there is a mode up there that could have more energy than we expect. Its just a small trend, and if I were Al Gore I could extrapolate that up into thousands of dBm ok, just kidding around some there - but it would be nice to get a wider view of the landscape

And thanx again for what you have already done - as I told Aaron, it could be important. I wonder if I sent you my resistor, if it would have the same effect Hmmm.

[Groundloop]

Harvey,

The scan was run in two passes, the first detected the background radiation
(in green) the next with the RA circuit running (in red). That way you know
how much background RF there is. Normally one should run this in a grounded
cage, but I do not have access to that. The pickup antenna is very close
(less than 30mm) to the circuit and if there was any high output of RF
energy then it will get that easy since the input sensitivity to the
spectrum analyzer is -120dBm.

I can't comment on the VLF RF radiation in your setup, only in my setup.
My spectrum analyzer can't go below 10KHz, so if it is VLF below that,
then I can't detect it.

Forgot, If you want any runs above 50MHz then I can do that.

Groundloop.

[Harvey]

Hi Groundloop,

Thanx for that analysis - were you able to shield the surroundings so that the energy shown is all from the RA resistor? I see an upward trend starting at about 40MHz and naturally wonder what the spectrum looks like between there and 200MHz. Of course I don't know what type of antenna you are using or if you have a cage you put the device in with the antenna, but the information is interesting.

I know that I have had wireless emissions here that have affected my Keyboard and Aaron had some he documented as affecting his touch lamp - but neither of us checked the band. Perhaps it is not RF, or if it is, perhaps VLF Either way it was wireless interference.

What do you suppose causes the asymmetric oscillation on a large part of the signal? Flat bottoms, jagged tops? I notice between 15MHz and 20MHz it seems more symmetrical. Perhaps this symmetry is important to the dielectric heating of the resistor. What is more, perhaps the lack of amplitude between 10MHz and 15MHz means the energy is being absorbed by the resistor. Just thinking out loud here, and interested in your thoughts.

[Harvey]

The original reason I started powering the 555 from the same battery as the load battery is because of that individual at ieee that denied your article and said they would never consider it in the future. That is a very troublesome mentality!

So, I powered the 555 from the same battery and was able to either produce heat with less power than it is even supposed to take to run the 555 or I could get the negative net wattage while running both from the same battery. In either case, the ieee point is quite pointless.

Now from what you told me that someone that thinks they are an expert in electronics claims the effects come from the capacitors on the 555 circuit, so what do I do, simply remove the capacitors to show that the effect is there effectively obliterating their argument. Next!

I'll put the caps back on and get back to work. Seems some people get so desperate to hold on to their claustrophobic world view they have to grasp at anything to keep them feeling safe and secure like what babies do with pacifiers and blankets.

Hi Aaron, enjoyed your video Very happy to see the probes grounded right at the battery. Did we ever find out anymore on the high frequency signal? I'm not sure what to think on Groundloop's RF analysis - I had RF interference in my Keyboard circuit for an absolute certainty and I do not doubt the RF effects you documented as well. Could it be that his resistor is not emitting like ours? If so, we should find out the reason ours do, or his doesn't - it could be important. If his is able to operate at the same parameters as yours, without the RF losses, he may get more heating than we do.

If I understood Poynt's points he was drawing attention to the internal capacitance of the FET and how it itself reacts like a capacitor to the circuit at certain frequencies. I really do not think any malice was intended there, honestly - just an effort to explain the very interesting results.

Cheers!

[Harvey]

Fuzzy, those are some very interesting waveforms. I am particularly focusing on the rebound of that very clean negative spike right at the gate turn-off time. The gate is clearly off, and the source pin on the FET drops to what appears to be -2.5V and then mysteriously rebounds above zero with virtually no Gate activity. The source is then driven into another -2V negative spike, apparently by the back swing of the load resistor via the FET body diode. This means the first negative pulse is occurring at the same time the drain is in a rising pulse condition. We need to see the drain and source on the screen at the same time for timing comparison - it is very important.

If I read your values correctly, your gate is switching about 12V and your Source Pin is being driven between approximately -2.5V and +0.75V - it is difficult to see the zero line, but a close approximation is evident.

I am very interested in seeing the exact same setup presented with the new equipment monitoring. Particularly, any frequencies above 10MHz that may be present and undetected by your scope. It appears I can see about 15MHz there - this is the stuff that causes dielectric heating!

The first negative spike has a width of about 100nS at the top. At those frequencies, the 250pF output capacitance of the FET will look like an 11ohm resistor to the gate pulse - in other words, the energy will pass right through it, but only in a capacitive fashion (AC). The gate drops to zero, and the source drops negative (see my video) and then rebounds because it is isolated by the dielectric of the gate-source junction. There is also about 13nH of inductance in there that plays into this a small bit at those frequencies. And then, after the rebound, we get the next negative push off of the inductive collapse. All very interesting.

Cheers!



ETA: Prior post with link to video

[dllabarre]

I bought quite a few caps from ebay over the years.
Mostly used but in perfect shape. They can be very
expensive if you buy those ratings new.

.

Thank you,

[Aaron]

big caps

@Aaron, @All

I need some HV capacitors.
2uF - 10uF capacitance at 4-5kV range.

I bought quite a few caps from ebay over the years.
Mostly used but in perfect shape. They can be very
expensive if you buy those ratings new.

You might be able to series up some identical microwave
caps. The HV caps I have 4000v 2uf someone gave me
and they are DC, which are preferable over the AC caps
in my opinion.

[Groundloop]

RF from the circuit

All,

Today I did a test to see how much radio frequency energy there was
radiated from the RA circuit.

Circuit version : http://home.no/ufoufoufoufo/anc_revB_sch.gif
Resistor: GRF20/100 10R 80W 6,5 μH.
Power: Lab supply, separate 12.0VDC for 555 IC, separate 12.0VDC for Switch.
Frequency: 2,4 KHz at approx. 3-4% ON Duty Cycle.
Input: 12.0VDC @ 0,04A indicated on lab supply.
Shunt: 0,25 Ohm 1%, 10,7mV average measured with DVM.

Spectrum Analyzer:

- Set to scan from 10KHz to 50MHz. Bandwidth 15KHz. Scan Step 15KHz.
- Pickup antenna less than 30mm distance from the 10 Ohm power resistor.

The scan did not pick up any RF energy above -80dBm. To give you a idea
of the low RF levels, -70dBm is equal to 100pW (pico Watt).

Conclutions:

It is fairly safe to say that the circuit does not radiate any significant level
of radio frequency energy to the surroundings.

Groundloop.

[dllabarre]

HV Caps

@Aaron, @All

I need some HV capacitors.
2uF - 10uF capacitance at 4-5kV range.

I know I'll need to create a bank to get close to these values.

I just need some part numbers from Digikey or Mouser or someplace.

All my searches on Mouser & Digikey come up with these poly film caps.
I'm not sure these are correct to use for devices like EV Gray Tube and other HV circuits. I see others using CANS and I don't see them coming up in my searches.

If someone could PM me with what they use, so as not to redirect this thread, I'd appreciate it.

Thanks

[Aaron]

no caps needed

Hi Aaron. I think you've aced this argument - but apparently I missed the general thrust here. Hopefully we'll hear more from Poynt.

The original reason I started powering the 555 from the same battery as the load battery is because of that individual at ieee that denied your article and said they would never consider it in the future. That is a very troublesome mentality!

So, I powered the 555 from the same battery and was able to either produce heat with less power than it is even supposed to take to run the 555 or I could get the negative net wattage while running both from the same battery. In either case, the ieee point is quite pointless.

Now from what you told me that someone that thinks they are an expert in electronics claims the effects come from the capacitors on the 555 circuit, so what do I do, simply remove the capacitors to show that the effect is there effectively obliterating their argument. Next!

I'll put the caps back on and get back to work. Seems some people get so desperate to hold on to their claustrophobic world view they have to grasp at anything to keep them feeling safe and secure like what babies do with pacifiers and blankets.

[FuzzyTomCat]

Fuzzy - please get hold of Lisa. I've emailed you her telephone number. Lisa has kindly organised something for you for the weekend.

Many thanks Lisa. We are all indebted. I hope we'll do your instruments justice.

Rosie

Hi Rosie,

Talked to Lisa at "Tektronix" and it's a done deal for the weekend ... I cannot thank her enough for this opportunity to further the understanding and the verification of our findings using equipment designed for these types of experiments. This is a really good day for the "open source" community and now possibly has made the value of what we all can do more credible to the main stream.

Glen

[witsend]

YouTube - Ainslie circuit without caps on 555 circuit

Some people amateurishly believe the negative effects on this circuit come from caps on the 555 circuit. Even if they do, it is still unconventional and there is still more leaving the circuit than going into it. In any case, this video shows no caps on the 555 circuit at all, and yes it will run, and the negative effects are still there. So, the argument that the effects are coming from the caps are completely erroneous.

Hi Aaron. I think you've aced this argument - but apparently I missed the general thrust here. Hopefully we'll hear more from Poynt.

[witsend]

Hi Fuzzy. Such interesting waveforms. I must tell you they're reaching the kind of chaos that we found over the resistor in our own tests. It may very well be that the magic is in the frequency? I'm beginning to get optimistic again.

Golly Fuzzy. You keep on keeping on. I'm blown away.

[Aaron]

Ainslie circuit without caps on 555 going negative

YouTube - Ainslie circuit without caps on 555 circuit

Some people amateurishly believe the negative effects on this circuit come from caps on the 555 circuit. Even if they do, it is still unconventional and there is still more leaving the circuit than going into it. In any case, this video shows no caps on the 555 circuit at all, and yes it will run, and the negative effects are still there. So, the argument that the effects are coming from the caps are completely erroneous.