Mosfet Heating Circuits

[Aaron]

common ground

P.S. I would like to see the 'Common Ground' variation of the circuit. If it's been posted, then please steer me there or I'll simply anxiously wait.

The common ground here is a bit different of a concept than the
plasma ignition stuff.

When measuring the resistor, a "shunt", or actually a current sensing
resistor like 0.25 ohms or so was in series with the ground and the scope
channel A was put across that to see the voltage difference so the
current could be calculated at that point.

On the timer circuit, I was using a current sensing resistor on the negative
rail from the same battery to the negative of the timer circuit - I think
that is how I had it wired. On this one, channel B for example could be
put across that to measure what the timer circuit is drawing as well.

But with the Tektronix 3054C, the grounds for the channels are connected
to each other. So if measuring both channels A & B at the same time,
having both probes across those resistors on both the resistor shunt
and timer shunt, the probes were interfering with each other.

So it is better to measure each independently of each other which is
probably ok but is more difficult to see their relationship with each other
in live time with a high degree of accuracy.

The Fluke123 that I also used has the probes for Channel A & B isolated
from each other so when measuring both A & B, neither will interfere with
each other.

So the common ground thing was really a reference to how the
Tektronix scope had the channels wired together. The circuit itself,
resistor/mosfet side and the timer are already common ground being
run on the same battery.

This is my recollection of the deal with the common ground issue with
the Tektronix - I noticed the readings of one channel would instantly
change when attaching a probe to the second channel.

[Harvey]

Hi Greg,

I found the images on Glens 'Devices and Components' Repository:
Device & Components - Windows Live


This Image shows all four scope probes connected to a common location:


And this image shows the actual common node 'Wire Tree' fabricated to do this. You can see the four copper protrusions over the white wires:


Attached is the original shot along with my suggested modification

[gmeast]

info'

Hi Greg,

I found the images on Glens 'Devices and Components' Repository:
Device & Components - Windows Live
..................................

Attached is the original shot along with my suggested modification

Hi Harvey,

Thanks for the links,

Greg

[gmeast]

isolated channels

.................................................. .................................................. ..................................................
The Fluke123 that I also used has the probes for Channel A & B isolated
from each other so when measuring both A & B, neither will interfere with
each other.

This is my recollection of the deal with the common ground issue with
the Tektronix - I noticed the readings of one channel would instantly
change when attaching a probe to the second channel.

Thanks Aaron,

I've been combing the Fluke info' an I just CANNOT find where it specifically says that the Fluke 123 has isolated channels, but the Fluke 190 specifically says it does. The PDF I have for the Fluke 120 series (123/124) specs says:
"Maximum voltage between reference leads:
Instrument has common grounds connected via self recovering fault protection. For different ground potential measurements between inputs use DP120 differential voltage probe."

... unless this means something other than what I think it means...?

mmm... so dunno'

Greg

[Aaron]

isolated grounds?

Greg,

Then the fluke 123 may not have isolated probes.

But I thought the channels were supposed to be connected
to a voltage that wasn't ground for a "ground" reference...something
like that.

Anyway, it's been a while and I might be remembering wrong.

There was a ground issue with the Tektronix and the Fluke had some
advantage over it in that regard - that for sure is accurate and I don't
recall all the details.

[jibbguy]

It has to do with the battery power.

If not stated specifically as "Input to Output Isolated" or "Channel to Channel Isolated" (and these terms are very precise); then the method is "Single Ended To Ground". NOT "Differential" (lol which is another precise term that is slightly different that "input to output isolated").

Single Ended Meaning that there is only passive resistance between the "Signal Low" of the scope, and Earth ground. This is what nearly all bench scopes are, unless otherwise stated (or without special probes).

However, when under battery power, the scopemeters are "isolated"... the same as a DMM is, because it has no connection to Earth. This is probably true when the charger AC "wall wart" is plugged in too (depending on the schematic of the charging circuit); but this would have to be checked to be sure.

The problems arise when the Signal Low of the Single Ended scope is attached to a spot that is Off Ground. If the potential difference is low (meaning the diff between the point Signal Low is at, and "Earth" referenced by the third prong of the scope's Mains power plug), some current can flow from Signal Low to Earth, possibly distorting the signal and inducing minor measurement errors. When the potential is large, it can easily burn out that channel (this is the single most common reason for Single Ended scope repairs, and is NOT covered under Warranty lol ).

Note: To get around this, sometimes folks cut off the third prong of the power plug (removing connection to Earth).... Which can be dangerous: If you do this, make damned sure that you are ABSOLUTELY POSITIVE that the AC plug is wired correctly (it is somewhat common to have Hot and Neutral wired backwards at some point in the circuit).... Because if it is backwards, the scope's chassis can be HOT and give you a serious Wake Up Call when you touch it (electrical shock is nothing to mess with).

[FuzzyTomCat]

Thanks Aaron,

I've been combing the Fluke info' an I just CANNOT find where it specifically says that the Fluke 123 has isolated channels, but the Fluke 190 specifically says it does. The PDF I have for the Fluke 120 series (123/124) specs says:
"Maximum voltage between reference leads:
Instrument has common grounds connected via self recovering fault protection. For different ground potential measurements between inputs use DP120 differential voltage probe."

... unless this means something other than what I think it means...?

mmm... so dunno'

Greg

Hi Greg,

I have the PDF information on the Fluke 199C ScopeMeter in my SkyDrive Public Folder this is the instrument used in the Quantum article research.

Regards,
Glen

[FuzzyTomCat]

Hi Aaron,

I was curious in the first PDF of yours http://www.feelthevibe.com/free_ener...slieheater.pdf I see in the experiment image the use of a "Fly Back" diode across the 10 Ohm "Load Resistor".

How long did you use the "Fly Back" diode in your experimental device?

Best Regards,
Glen

[Aaron]

battery power scope

It has to do with the battery power.

That Tektronix I believe has a battery bank available, it just wasn't
included when I was using the scope so it was usually wall power. A few
times I hooked it to an inverter that was powered by a car battery and
did this for a few tests. Especially the ones Lighty walked me through.
I might have even had it on an inverter for some tests I did for Harvey.

My own Goldstar scope that I used in the beginning, I had that running
from an inverter powered by a car battery because the Isolation transformer
I borrowed from Peter never worked for some reason. I started doing that
when doing the Gray motor experiments because even with the isolation
transformer - as soon as I connected the scope to the circuit, the breaker
would pop - luckily the scope was never damaged. Anyway, that is why
this scope was almost always down on the ground, that is where the
battery and inverter was. When I was using that scope in the very
beginning, it was only just that one scope.

The Fluke 123 - I ran it from the battery most of the time. I still don't
remember what some of its advantages were over the 3054C but it
was explained to me by more than one person. This scope does have
some port on the side for optically isolated probes, etc... it can also be
used for a data port to download all the data capture but I never had
the cable or software.

[Aaron]

flyback diode

Hi Aaron,

I was curious in the first PDF of yours http://www.feelthevibe.com/free_ener...slieheater.pdf I see in the experiment image the use of a "Fly Back" diode across the 10 Ohm "Load Resistor".

How long did you use the "Fly Back" diode in your experimental device?

Best Regards,
Glen

Glen, that was the first test I did and you can see I even had a 10 ohm
"shunt" resistor. lol - that is why the battery was receiving such a
potential charge that kept pushing up the battery voltage.

Anyway, I used that flyback diode in the very beginning for how long I
don't recall. But after a while, I did probably half/half - half the experiments
had the flyback diode going back to the top of the resistor and half
the experiments didn't have one.

I remember at one point, Rosemary told me that the cop17 test were done
with the flyback diode even through the quantum article didn't show it.

I think that was all posted in the original cop 17 thread.

It was like she had a sudden realization about it - or it was the other
way around. I spent literally a few hundred hours on voice skype chats
with her during quite a bit of those experiments - mostly after I got the
Tektronix here - I then set the camera up so she could see the waveforms
on the screen.

Eventually, I probably did as many experiments with the diode as without.

With the diode, about half were to the top of the resistor and the other
half were split between charging a secondary battery or a capacitor.
There is a LOT of promise with charging a cap with the recovery for
various uses - feedback to the front isolated so the front battery doesn't
see it - or timed discharges of that same cap back to the same inductive
resistor the spikes came from, etc... I want to go back to some of
those tests at some point.

I also did quite a few tests with diodes bypassing the mosfet's internal
diode and got to the point where I was able to get the same heat for
much less power. To my understanding, that diode in the mosfet is
garbage. I think you might have been doing some of those tests too didn't
you? I think you brought me a few high speed diodes when you came to
my house but don't remember if they were for bypassing the mosfet's
diode or if they were for putting across the resistor.

Those tests are worth doing too - to increase the efficiency of how the
mosfet itself was running.

Anyway, I think I used that flyback diode on that particular first experiment
circuit for the entire test until I got some larger resistors. That one was
a pretty small one. Even after I got some bigger resistors, I still used the
flyback diode on quite a few tests but also did quite a few without.

[gmeast]

specs

Hi Greg,

I have the PDF information on the Fluke 199C ScopeMeter in my SkyDrive Public Folder this is the instrument used in the Quantum article research.

Regards,
Glen

Glen,

Thanks. Just downloaded them. They're expensive.

Greg

[gadh]

help with heat measurements

Hi all.
i hope this is the right thread to post for this subject.
i'm continuing my tests on the Ainslie (MOSFET heating) circuit, after a few months i did not have time to promote this issue.
now i'm in the middle of the heat testing. first i tested in an equivalent DC circuit, in which i adjust the current to be stable at rates of 200/400/600 ma, and i measure the heat rise by time with a multimeter and k-type thermocouple probe. the probe is measuring the temperature rise of a distilled water tank (650cc) in which i put the load resistor.

so far no problem. but now i started testing the Ainslie circuit which uses pulsed DC current, and the multimeter shows weird results ! it jumps immediately to 36 degrees (all celsius) (while ambient is 24 deg.) and then almost immediately to 50-70 deg. and continues to fluctuate between these values. the actual water remperature does not change in this time. the probe does not touch the load resistor and the water resistance is between 1-2 megaohms (this value also changes , depending on the scale i choose - 2 mohms, 20mohms, and also by time it changes, so its weird too...).
the distilled water label shows "0 micro-siemens".

could someone help me understand why the heat measuremnt goes crazy ?

[Harvey]

Hi Gad,

Really good to hear from you

Honestly, there could be many causes for this, but the most likely is RF getting into the meter or probes and affecting the readings.

Both Aaron and myself observed strange RF behavior with this system and Glen too observed magnetic influence on his monitor so we know it can influence nearby things.

More details may help us analyze the problem - and you may want to try putting your measurement stuff in a Faraday Cage appropriate to the frequencies you are running at.

Short on time here, but will check my messages later.

Cheers,

[gadh]

hi Harvey.
when you have time, please tell me which details you need in order to point me to the cause of this behaviour. meanwhile i'll try to assemble a small farady cage for my probe.

[Guruji]

Mosfet heater

Hi all.
i hope this is the right thread to post for this subject.
i'm continuing my tests on the Ainslie (MOSFET heating) circuit, after a few months i did not have time to promote this issue.
now i'm in the middle of the heat testing. first i tested in an equivalent DC circuit, in which i adjust the current to be stable at rates of 200/400/600 ma, and i measure the heat rise by time with a multimeter and k-type thermocouple probe. the probe is measuring the temperature rise of a distilled water tank (650cc) in which i put the load resistor.

so far no problem. but now i started testing the Ainslie circuit which uses pulsed DC current, and the multimeter shows weird results ! it jumps immediately to 36 degrees (all celsius) (while ambient is 24 deg.) and then almost immediately to 50-70 deg. and continues to fluctuate between these values. the actual water remperature does not change in this time. the probe does not touch the load resistor and the water resistance is between 1-2 megaohms (this value also changes , depending on the scale i choose - 2 mohms, 20mohms, and also by time it changes, so its weird too...).
the distilled water label shows "0 micro-siemens".

could someone help me understand why the heat measuremnt goes crazy ?

Hi Gadh it's amazing what you're saying so do you mean that if I put a JT to this circuit I can hook it to a water heater?I understood rightly?
Thanks.