Measurements

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Vidura posted this 21 July 2019

Hello Friends, It occurred to me to post some lines regarding the measurements of Devices under Test, and want to invite all who are interested to discuss in this thread opinions, suggestions, techniques of measurements. Most Researchers know that testing of in and output power, COP and efficiency is an important tool when working on AU Devices, but also that it can be very tricky to achieve really reliable results. For this reason it would be helpful to elaborate the best possible convention for trustable measurement techniques and practice. Vidura

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Chris posted this 21 July 2019

My Friends,

Vidura is right. When Experimenting, I have always said look for the Effects, they will lead you to a greater understanding.

However, when making COP Claims, we must be sure to be accurate, to not kid ourselves and not mislead others.

If your not sure, then leaving an open ended statement is damaging for Us, our credibility, making a statement of "I got COP = 1.3" or what ever and not backing it up with any data does make us look like ammeters and we will be laughed at.

So please, we have Measurement Protocol on this forum, and it needs to be followed!

Many here are very skilled and can help if you need help with measurements!

Resource: Measuring AC Power. DC Power is easy just: V x I with big smoothing Caps.

 

New Rule: Any COP > 1 Claims must be accompanied by Measurements please!

 

   Chris

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Fighter posted this 22 July 2019

Hi Chris,

DC Power is easy just: V x I with big smoothing Caps.

Not really. I also thought the same that's why I trusted my DC source's readings because I checked it regularly with diverse loads and always it did shown correct readings.

Remember we're researching devices which according to current physics shouldn't exist and the measuring instruments on market are made according to the current physics. Take a look at the following video where all the readings are correct on all instruments (including the DC source's readings) with a usual load until I connect the ZPM then all the readings (using various measuring methods) become very different.

For now no matter how many big caps and diodes I put on DC source's output the readings are still different. So here I have no doubts about the output as I see 2 x 12V/55W light-bulbs shining, as I didn't expected here is a problem measuring the input. I was as sure as you about the easiness of verifying input.

However, when making COP Claims, we must be sure to be accurate, to not kid ourselves and not mislead others.

I'm not here to mislead anyone. I presented my reasons at the beginning of my thread. I have so little free time I would never waste it doing this (not even talking about the money spent on this).

I put all the data I have here, spent a lot of time presenting it in details including videos and asked others to try, to prove me right or wrong. Nobody tried to reproduce it.

Testing it with different power sources and measurement tools would be helpful, it's called third-party validation. It's not possible for a single person to make so may suggested experiments in so many directions, that would be a 24 hours per day full job. What we do here is to present our experiments and our conclusions (which could be right or wrong) so others can try and have their own conclusions.

These devices can only be fully validated when others reproduce it, there is no other way. I was silent a long time here and decided to post only when I was 100% sure based on the data I had at that moment.

To be honest I never imagined there could be something wrong with the input readings, my concern was to find a way to get exact numbers about the output. Even now I'm not 100% sure there is something wrong with the source's readings, actually on input I have 3 different readings from 3 different ways of measuring the current. Still looking for ways to find which reading is correct.

So I will continue my experiments and present them here in the ZPM thread so others can try, just wanted to present my point of view about this topic.

Chris posted this 22 July 2019

Hey Fighter,

I believe, reading back, you did not make any COP > 1 Claims, you said:

I'm creating this thread in order to present a device which I think is a overunity device.

 

Clearly stating you weren't sure.

Please, what I wrote was not about you, its a safety net, so all visitors can be assured when visiting, if a Claim is made, then they can be sure we have done the best we can to verify it.

Don't worry Fighter, I very much appreciate your work and the way you presented your work!

My statement is just so we are all protected and all taken serious! I am sure we all want this do we not?

   Chris

 

P.S: I believe your device is one of the best we have presented, so any out there wanting to learn more, your ZPM is the best place to start after The Mr Preva Experiment.

Fighter posted this 22 July 2019

Thank you Chris. Considering the troubles I have in determining the input as you can see in the latest video (about output I'm very sure it's a lot of power there), I was thinking the post is related to the experiments I presented, sorry it's 6:12 a.m. almost morning here (worked on presenting the tests I've made in weekend) so for sure my mind is far from fresh right now

I agree about the necessity of finding methods for accurate measurements, as you can see my video is a first and clear example of the issues encountered with this kind of devices even when making DC measurements...

Chris posted this 22 July 2019

Hey Fighter,

Accurate Measurements can be obtained using the circuit here.

We have the best people here, all very valuable human beings!

   Chris

Fighter posted this 22 July 2019

Question: if our fancy digital measurement instruments are so unreliable when dealing with high-frequency, pulses etc. what about using analog devices like this ?

Are they reliable ? I mean we don't need measurements with 3 digits when we're experimenting. Does something like this with an adequate current-sensing shunt be more reliable ? I never used something like this but I just bought one, it's 5A but I don't think it can withstand 5A directly so I should find and adequate shunt for it. Does it need to be tested and calibrated with that shunt ? What if I can't find a 5A shunt, could it work with let's say 10A shunt ? Should it be re-calibrated ?

The reason I'm asking this is because if analog measuring devices via shunts are reliable I'm thinking about making a custom DC source with incorporated measuring circuits which could be trusted in any conditions.

I mean if we're experimenting with devices Tesla worked on and our fancy digital measuring devices are not reliable why not using analog measuring devices like Tesla used ?

For example I could take an auto-transformer like this:

https://www.conexelectronic.ro/en/autotransformatoare/15369-AUTOTRANSFORMATOR-REGLABIL-2-8-A.html

put an adequate bridge rectifier on it then on output I can have shunts connected to digital but also to analog voltmeters and amperemeters, everything packed in a adequate case with a panel where analog plus digital readings can pe shown. Also it can have direct AC output which can be useful when needing a specific AC voltage for experiments.

Of course if would cost and take time to build but it's worth it as long as the result would be a platform with accurate readings no matter what kind of device it's powering.

So the question is: is analog devices + shunts combination reliable ? would be reliable (in terms of readings accuracy) a custom source like the one I just described ?

Vidura posted this 22 July 2019

Hey Fighter, This simple coilwound meters can be a good choice when dealing with DC currents, although of these have transients components, spikes or high frequency components. They can be used with shunt resistors to adjust the range. Note that this instruments are basically for DC , in order to measure AC a rectifier and filter have to be connected. This can be quite good for frequencies up to several kHz, if components are accordingly selected. But of we deal with very high frequencies it becomes tricky due to increased sensitivity to parasitic inductance and capacitance. Also most components are limited regarding their high frequency capability. Regarding the autotransformer, it is only for a very limited frequency range, for example mains frequency. But the former method with the simple meter, combined with a simple capacitor-choke filter should be fine for a reliable input measurement on the input of your ZPM module. Although the readings will be more broad , not so much resolution, it should be enough for a estimation of real input power. Regards Vidura.

Fighter posted this 22 July 2019

Hi Vidura, thanks for the explanation. The custom source I was thinking about is actually a DC source with variable voltage driven by that autotransformer + bridge rectifier. On the output of the bridge rectifier I would have shunt and in parallel on that shunt I would have digital + analog ampere-meters. Also it would have digital + analog voltmeters on output. So if in case the device powered on by the source is making the source's digital measurements inaccurate (like in my case now) I will still have reliable readings on the analog amperemeter and voltmeter. Additionally (if needed) I would an AC output with variable voltage but with 50Hz frequency taken directly from the autotransformer. So could I count on the analog voltmeter and amperemeter on the output of the source to be immune to pulses, ripples etc. which could come back to the source from the device it's powering on ? I'm talking about DC output which with my actual DC source seems to mess up with the digital measurements I'm using to check amperage taken from  the source (as you can see in my video posted here the readings from source, amperemeter and voltmeter put in parallel with resistor - all are showing dramatically different amperage values). I mean let's say if I would have also analog amperemeter plus voltmeter on the panel of my actual DC source would they show correct values and be immune to the problems the digital amperemeters and voltmeters have now when I power on ZPM and try to make measurements ?

About using filter as you can see in my video I tried with a Schottky diode on the source's positive output plus a big electrolytic capacitor in parallel on the source's output but the digital measurements on amperage are still messed up - big differences between what the source is displaying, what the amperemeter is displaying and what the voltmeter in parallel on that 1MO resitor is displaying. What about the capacitor-choke filter, how would this filter should be built ? I have some small torroidal ferite cores, I can use them to make a choke coil, how many turns and what wire diameter I should try to eliminate the problem I have when measuring DC amperage with digital instruments ? Thanks for your explanations.

Vidura posted this 22 July 2019

When we are working with devices using frequencies of several hundred kHz we have to take in account that currents will not necessarily take a closed path as one would expect. At this frequencies one wire transfer of power is common and earth ground plays an important role as well. After watching the video of your measurements I would suggest isolating the powersupply and measurement stage for the ZPM with two chokes, one on the positive and one on the negative wire , followed by two different capacitors, one electrolytic type as you used and one or more smaller ones low ESR type(tantalum, ceramical), near the device under test. With this technique it should be possible to block high frequency transients to a mayor degree. The chokes should have wire gauge according the expected maximal current, the number of turns depending some on the core material , more turns will block down to lower frequency. You can give it a try with what you have at hand anyway. And yes the simple analogue meters are much less prone to react to transients and HF components. If using shunt resistors better avoid wire wound type, as they have more parasitic inductance. Another observation: the continuously changing values on the supply display is typical when HF interference is present on digital meters. I hope this helps something. Vidura.

Fighter posted this 22 July 2019

Thanks Vidura, yes, your explanations helps me a lot to figure out what's going on and how to address these issues. I will read your answers multiple times to make sure I understand them and I'll try your suggestions.

Chris posted this 23 July 2019

My Friends,

I think we need to take a step back.

Fighter has shown a machine that is doing a lot of things, the most important thing is that it is interfering with the Power Measurements! At least it is interfering with the Power Measurements with the Digital Multimeters. Again a common problem.

With Precision Metal Film, Metal Strip, or Carbon 0.1 ohm Resistors and an Oscilloscope, accurate measurements can be taken.

Fighter will get to this when time and resources are available.

Fighter and Vasile are right, the Globe will no doubt be close to some sort of Approximation.

From my understanding, this thread was meant for those that were loosely throwing around COP > 1 statements in their Posts?

Please remember, Fighter did not do this.

   Chris 

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Vidura posted this 23 July 2019

Chris is right , we can use shunt resistors and a oscilloscope for accurate and reliable results, if measurement for DC (also with HF components) and AC sine waves is required. Some more advanced scopes also have math functions integrated to get RMS values for other than sine shaped waveforms. Specially on the output of many devices we will get composed waveforms, or harmonic distortion. If we don't have equipment to make correct measurements of composed waveforms, a good and cheap method is the calorimetric measurement, which is by the way widely accepted in the most orthodox scientific community. If we we have a device that outputs a complex AC wave, and maybe hardly can be rectified or filtered we can use a resistive water heater with a convenient resistance (similar to our load) measure the start and end temperature in a given time interval, using a scaled amount of water. Then we can calculate with good accuracy the exact power dissipated by the resistance in the time interval. We can use the specific heat of water, with is 4.186 w/s to rise the temperature of 1g water 1°C. Although the actual value is a graph depending on temperature , the deviation is very small, and if we keep the temperature for measurements between 25 and60°C the error will be less than 1%. Water heaters are available for a broad range of power , and different voltages. But when used for calorimetric measurement the only value that is important to us, is the impedance (resistance) to Mach the requirements of our DUT. Regards Vidura.

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Fighter posted this 28 July 2019

Hello Fighter,

This is in response to your video:

I will post some suggestions and some questions. I hope you will take them as constructive as posible because this is how they are intended.

Hi Vasile, no problem, any suggestion is welcome, the only problem is I don't have enough time to test all the suggestions, that would be a full-time job, that's why I'm sharing the information in my thread, hopefully others will duplicate the device and make experiments in different directions as they want.

1)At 03:41 in the video it says 1M Ohm. I think you meant 1 Ohm. Correct?

That's correct, it's one ohm. In the same video you'll notice I was saying miliampers instead of microfarads when talking about that capacitor, I was kind of tired when I made the video, my apologies.

2)At 06:19 you say the luminosity of the light bulb is confirming you have close to the amperage your source is showing, meaning close to 0.060 mA. It is best not to judge amperage value virtue of the luminosity of the bulb, because it can be misleading. You are using DC in that example, so I can tell you have at least 1Amp flowing thru it. I atached even a picture with a 12V, 55 W bulb. You can see it draws way more than 1Amp. (Picture atached)

3)Again at 07: 32 you make the same asumption like at 06:19.

I was saying that between the 3 readings I had (DC source's display, amperemeter and voltmeter on shunt) the closer reading would be DC source's readings based on light-bulb luminosity. I saw your photo, the problem there is you have no voltage even if you have current; in my case I'm pretty sure I have 24V on input as you can see in this video:

Those two light-bulbs in series confirm that on the output of the DC source is in fact 24V and the voltage displayed by the source is not wrong.

4)At 09:49 you say why different readings between all the equipment? You have a 1 Ohm resistor over there, but lets suppose that it isn't exactly 1 Ohm and it is ±0.1 Ohm, you will have a diferent voltage reading which will lead to a different amp reading, which evidently would be wrong if judged as a 1 Ohm resistor. Another point would be that the majority of multimetres, as you have, measure well only up to 15-20 KHz. The really expensive ones can measure over that and even then only to 50-100KHz range. To solve this problem you need an osciloscope which goes up to MHz as far as voltage readings are concerned.

Don't foget there is DC on the output of the DC source. Even putting a filter made from one fast Schottky diode and a big 10,000uF/60V electrolytic capacitor on DC source's output while making measurements will not change the readings; so why talking about measurement instruments having issues at KHz when they're actually measuring DC ?

Conclusion:

1)My conclusion is simple. Your power source does not indicate well Amperage and maybe even Voltage. Why? It appears your S.G. and/or the black box transistor thing you have there plays the biggest role. Either the high frequency of the switching is messing up with the reading or you have a common ground issue where power flows from the P.S. positive thru either one or both of the S.G. and/or the black box, to ground.

All the best,

Vasile

I just shown in my previous video that the DC source indicate voltage correctly. Also with that noise filter the amperages indicated by DC source and other measuring instruments remain the same so the cause of different readings is not the noise coming back. The "black box" meaning the MOSFET driver is not connected to the power grid, it's connected only to the DC source's output so there is no power leak through it. Also you should see the transformer in that signal generator, I doubt it can handle amperes leaking to the power grid through it, it would be gone for a long time if that would happen. About the high-frequency messing up with the readings, I already mentioned that I tried with that noise filter and saw no changes. But let's say there is high-frequency on the DC source's output, it should mess with all the instruments not only with the source. Why other instruments show amperes while the source show miliamperes ? Makes no sense. So as you can see there is no conclusion yet on these issues. That's why I'm using my free time to share this information, so others can replicate ZPM and start experimenting with it else there would be just an exchange of hypotheses without real advance. Thanks.

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Vidura posted this 28 July 2019

Hello all, Only a brief comment about filters: For an effective filtering of interference in a DC line the LC filter combining inductors and capacitors is a good and effective methodology. There can exist common and differential mode interferences, if we use at least one inductor in the positive and one in the negative wire combined with some capacitors in parallel, we can block both types of them mostly if inductance and capacitance values are choosen according to the frequency ranges. Note that a combination of capacitors and diodes will not block interferences efficiently. Vidura.

Fighter posted this 29 July 2019

Vasile, I agree with that but that doesn't mean what's powering that bulb is entirely provided by the DC source. Please take a look in the latest updates on ZPM thread, in some experiments I posted there you will see the oscilloscope reading Vpp=240V. That voltage is not provided entirely by the 24 volts of the DC source either. Regards.

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Fighter posted this 29 July 2019

Vidura, noted, so that diode-capacitor filter is not very efficient. I have on my list to create an inductor-capacitor filter, thanks, will take care of it when I will have some time.

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Chris posted this 31 July 2019

Hey Vasile,

Please forgive me, but that's a very long way around a simple problem don't you think?

With some 0.01 Ohm precision Resistors, Fighter could have a very accurate result in about 10 minutes! I have already provided the circuit for measurements: here.

   Chris

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Chris posted this 31 July 2019

Hey Vasile,

 

I understand that perfectly and I want to say something here:
1) If we are talking about measuring after the power source, I think he believes that somehow the power is coming from the ZPM to his power source, so it would be irrelevant measuring like that, because once again, the power could come somehow from the ZPM.

 

Yes, the Power does reverse. Yes Energy does come back to the Source, its an Impedance and the DUT see's the Power Source as a Load. This Power coming back reduces the Power Input, Reactance, and yes as a result, the Input Power reduces the more load is applied.

Most certainly not an irrelevant measurement, this is an important understanding step, very important.

One can see on the scope when this occurs, as a Power Factor Correction: 0.0 or less:

 

 

 

2)So, I recomended measuring before the power source, like between the plug of the power source and wall power. I didn't want him to go near with his hands on live wires, that is why I recomended the wattmeter. Of course as you said the resistor method would be more accurate.

 

Yes, a good idea to see what the power is doing. Certainly an experiment that can be performed once more is understood about what's going on. The Input to the Device Under Test ( DUT ) is from the source, and from there, in between the Source and the DUT, the Input Power must be measured:

 

The Power Source must be measured as a separate load because of the condition the Power Source is exposed to. Again, it simply is an Impedance to the DUT.

I have always said, study closely the Currents, the applied Right Hand Grip Rule will guide one from there. Truly, the important thing is the Currents.

I also encourage extreme care with these Devices!

   Chris

 

P.S: 

the power could come somehow from the ZPM

 

If Fighter replaced the ZPM with a Honda 3 Kwh Electric "Generator" would that explain the somehow part? Faraday's Law of Electromagnetic Induction is the Somehow. wink No Magic, No Mysticism, please believe in todays Tech.

I hope we have cleared this part up?

 

Vidura posted this 31 July 2019

Hey Fighter, I have seen your scope measurements before, there are some odd things actually. It is likely, almost certain that there's an interaction between the DUT and the power source. I have noted that the waveform is changing when you invert the probe polarity. This could be a effect of ground connection of the scope. Maybe by filtering you can get more accurate results, provided that the filter capacitors don't prevent the DUT to work properly. I mean the current would circulate between the device and the filter capacitors instead the powersupply, and actual current and voltage could be measured between the filter and the supply. You should also take measurements of the voltage with the scope, and multiply V RMS and I RMS. Vidura.

Fighter posted this 31 July 2019

Hi Vidura, but it is recommended to make sure the scope is grounded, isn't ? So I made sure my scope is grounded and the source is floating (not grounded) to avoid blowing up my scope while measuring circuits powered by my source.

Jagau posted this 31 July 2019

Hi my friends

I use on all my measuring instruments on insulation transformer is strongly recommend.
I also run my oscilloscope on an inverter ,12volts DC battery to 110volts AC,  that works very well too, 

however, for an oscilloscope, a floating ground is a way to avoid a problem but accuracy can suffer.

So the ground is not linked


Jagau

Vidura posted this 31 July 2019

hey Fighter,
Yes it is recommended to ground not only Scopes, but virtually all electric devices for safety reasons, it is not likely that a device will  be damaged for using it without ground connection. I use my old CTR scope mostly without earth ground, also the methods proposed by Jagau are correct and can be safely used. Anyway probably when the device is separated from the power supply by a efficient filter it will show a smooth DC like trace on the scope, with or without grounding.

Vidura

Chris posted this 31 July 2019

But I already did that (fragment from that post below) I just used half of a shunt borrowed from Cd_Sharp. But what I saw was strange, I saw currents going in both directions through those resistors.

 

Hey Fighter,

Those Resistors might be Wire Wound Resistors, CD if you can verify the model you bought, that's might be why you see the strange currents. Here is the 15FR250E Datasheet, saying its a Axial Wire, that should be ok.

 

We can not use Wire Wound Resistors at high Frequency, only low frequency. Its a big no-no, so if these Shunt Resistors are Axial Wire, they should be ok.

Another thing to do is shorten your Wires to the machine, short as possible, this might help. 

At the end of the day, the ringing just might be a real effect coming back out of your ZPM. Perhaps a Harmonic?

   Chris

 

P.S: Sorry everyone, I made a mistake and Fighters post was accidentally deleted embarassed

Fighter posted this 31 July 2019

P.S: Sorry everyone, I made a mistake and Fighters post was accidentally deleted embarassed

No worries, it's not a big deal

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Chris posted this 01 August 2019

My Friends,

The missing post was in reference to this post: here. Sorry again!

In the below image, we see two numbers with a red line above them:

 

Both numbers are very different! Average or Mean: 172mV and Vrms or Voltage Root Mean Square: 610mV.

Importantly, we have a DC Power Supply! Direct Current meaning one way only! At lease if one is running a Linear Load like a Light Globe!

All Current below the faint turquoise line I have drawn in here:

 

is Negative Current, its below the Zero Graticule Line of the Probe measuring it.

The Root Mean Square is 610mV across a 0.25 Ohm Resistor, this is approximately: 59.512 Watts input to the ZPM.

At the same time the Scope is saying we have 172mV across a 0.25 Ohm Resistor, this is approximately: 17.082 Watts input the ZPM.

Both figures cant be right! So in this case which one do we trust?

We know Power is coming back at us, the ZPM sees the Source as a Load! The ZPM is trying to Power its load, being the Power Supply.

So what do we have? What are the facts?

  1. 172mV across a 0.25 Ohm Resistor, 0.688 Amps, approximately: 17.082 Watts input the ZPM.
  2. 610mV across a 0.25 Ohm Resistor, 2.44 Amps, approximately: 59.512 Watts input to the ZPM.

 

 

NOTE: RMS is always positive, it does not give an indication of the direction of power.

Now, I ask others to correct me if I am wrong!

You should use Mean, which is an integration ( Addition ) of the instantaneous power readings ( each sampling point on your screen ) over as many Cycles you have on your screen, which is time, which yields total Energy for this time interval.

This is because your DUT is Non-Linear, and your Source is DC, the DUT sending Power back to Power the DC Source!

With a Linear Load, and an AC Source, you should use RMS most of the time.

   Chris

 

Vidura posted this 01 August 2019

Good tutorial video, in my understanding basically the mean value would show a DC offset in such a complex waveform, we could define if in average more current flows in one direction limiting the measurement by cursor triggering to one cycle. But what's about the power factor? The real power in any point of the cycle of a sine wave or a complex waveform depends on the phase angle to the related voltage. I guess that the area measurement could be used if the value of the capacitance is known, as in the example in the video, but I don't have experience in this, as I don't have a digital scope. Although this tests can be useful for understanding the behaviour of the interaction of the DUT and the power source, for a input power measurement I would prefer to go a step backwards using a filter , and simply take a reading of current and voltage on the quiet side of the circuit. Vidura.

Jagau posted this 01 August 2019

A good explanation of the difference between mean (average) and RMS

which is to say:

Average value = 0.637 × maximum or peak value, Vpeak

RMS value = 0.707 × maximum or peak value, Vpeak

in terms easy to understand. here is the link:

https://www.electronics-tutorials.ws/accircuits/average-voltage.html

Jagau

Chris posted this 01 August 2019

Hey Vidura, Jagau,

@Jagau, thanks for the excellent links!

@Vidura, I agree, yes DC Offset, what is the definition of DC Offset:

DC offset is an imbalance that sometimes occurs in A/D converters ( see WFTD archive “A/D Converter“ ). When working with audio it is desirable to have only the audio program material passed through the signal path. Almost by definition audio, being a periodic waveform, is an AC (Alternating Current) signal.

Ref: www.sweetwater.com

 

Note: A/D converters = Analog to Digital converter.

Note: Mean or Average can be both Negative and Positive! Unlike RMS, which is only Positive.

The above video shows and states: ( 1 : 07 )

 

the mean value or average is computed by summing the value of each point and dividing by the number of points.

 

Because we are using a DC Source, Direct Current, not Alternating over Time in any way, we should only ever expect to see one polarity of Current, but we do not!

NOTE: If Fighter were to measure Zero Mean Current, then equal Current is going out as is coming back to the DC Power Source.

If I can reference the above video again: ( 1 : 16 )

if a signal is as negative as it is positive, that is if its symmetrical around zero, the mean value will be zero.

 

We see the DUT pushing Current back, already covered. If the ZPM uses zero mean current, then the Energy used in the ZPM is Zero.

The Mathematical function to Integrate (  ) is just, a series of additions:

 

Taking all the Sampling Points the Scope has taken over the time period, adding them all together and dividing by the number of points recorded. When a Scope Samples at say 5GHz per second, a common sampling rate today, that means 5 Gigabits per second are recorded. There are different methods of recording:

 

This guy is awesome!

His example: ( ( 5Gs / Sec ) x ( 20μs / Div ) x ( 10 Div ) ) = 1,000,000 samples

NOTE: Each pixel, representing the waveform, drawn on the Scope Screen is a Potential Value, its not related to the direction of the Current, in this case, the Polarity, the amplitude above or below the Zero Graticule Line for the Probe, determines the direction of the Current. Meaning if the Value Recorded is Negative or Positive.

Our Scope, if all points are Positive, then the Active power from the DC Source will be Positive Power, in the direction of DC Supply to Load.

The Average, or Mean of those points over the course of the Scopes Memory captured is the Average power in our case, measuring V and I over Time with Instantaneous Measurement Points.

Here is a brief example of the Points being measured with DC and a Linear Load:

 

So what do we have?

Scope Probe is set to 1x, but in the scope settings I have 10x set on the Probe. The Sense Resistor, a Metal Strip Through Hole Current Sense Resistor, is a 0.1 Ohms Resistor, so what I read on the Scope is the Current: 977.7 milliamperes at 4.8 Volts = 4.693296 Active Watts, because we have DC with a Linear Load.

Remembering: Watts is equivalent to Joules per Second. One Watt = one Joule per second. Energy over Time.

Above you can see, RMS and Mean are pretty much the same: 977.7 vs 977.3 mean.

With a Linear load, we don't have a problem, but as soon as the Load is non linear, we get a much different story. Again the Sampling Points become Negative, and Current is being returned to the DC Power Source.

Not something you would expect to see on average, in a DC Circuit.

   Chris

cd_sharp posted this 01 August 2019

Hey, Chris the resistors Fighter is using are non-inductive. I have been using them for a long time with good accuracy at any frequency.

"It's just the knowledge of the coils and how they interact with each other" (Steven Mark)

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Chris posted this 01 August 2019

 

Hey, Chris the resistors Fighter is using are non-inductive. I have been using them for a long time with good accuracy at any frequency.

 

Thanks for verifying that CD.

We can have Non-Inductive Wire Wound, which we can not use to verify Currents in a High Frequency Machine:

 

If only the potential was realised?

So all Wire Wound Resistors should be our goal to eliminate from our measuring toolkit.

 

All components have a little bit of the three base quantity's:  Resistance, Inductance and Capacitance

We can not eliminate Inductance and Capacitance completely, but we can minimise it!

   Chris

Chris posted this 06 August 2019

Guys, this is a repost, for information purposes:

 

Hey Fighter,

This is correct! The RMS Values are including the Power being returned back to the Source and not giving you an indication of the Direction of Current.

Direct Current, is a unidirectional Current, its not supposed to Alternate over Time or it is then AC, Alternating Current.

 

The quote goes on:

E.G: The scope records: 0123456789876543210.

Now we Integrate ( Series addition ) : 0 + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 = 81.

Now divide by the number of points recorded: 81 / 19 = ‭4.26315789.

‭4.26315789 is the average.

 

What does this mean? It means we can split the Triangle above the Mean line, down the middle, and put the two sides in the open area on the ends, the area is the same. This gives us a perfect Mean value. The shown RMS Value you can see is well above the mean height! There is no even distribution of the Waveform above the RMS value to the ends of the Wave shape. The area is not equal to the open area on the sides under the line!

The reason straight DC is so easy to measure is because its a straight line:

 

 

The area under the Straight Line, the Waveform is a Rectangular Box: H x W = Area. 977.7mV x 1t = 977.7mV

 

NOTE: The ZPM is a NON-Linear Load.

Now in the ZPM, if we use RMS, we cant include Power coming back as USED Power, which is what RMS power setting is doing! This is wrong!

Also NOTE: RMS is fine for Linear Loads! It will measure almost the same as Mean! See Here.

RMS is Root Mean Square, the equation is fairly straight forward:

 

See www.electronics-tutorials.ws for much better information on all this.

So we could say:

int TotalPoints = 19;
double Integration = Math.Pow(0, 2) + Math.Pow(1, 2)
                   + Math.Pow(2, 2) + Math.Pow(3, 2)
                   + Math.Pow(4, 2) + Math.Pow(5, 2)
                   + Math.Pow(6, 2) + Math.Pow(7, 2)
                   + Math.Pow(8, 2) + Math.Pow(9, 2)
                   + Math.Pow(8, 2) + Math.Pow(7, 2)
                   + Math.Pow(6, 2) + Math.Pow(5, 2)
                   + Math.Pow(4, 2) + Math.Pow(3, 2)
                   + Math.Pow(2, 2) + Math.Pow(1, 2) + Math.Pow(0, 2);

double Average = Integration / TotalPoints;

MessageBox.Show("RMS: " + Math.Sqrt(Average));

RMS: 5.07314913098986

 

Note: a small difference: 5.07314913 RMS vs 4.26315789 Mean, the difference: ‭0.80999124‬. The values often vary a little between RMS and Mean, but with a Non-Linear-Load, Mean must be used.

Note: I have used the same numbers in this example, RMS Voltage and Mean Voltage readings on the scope can be different, so please be aware this example is only that, an example.

Note: (81 / 19)2 is not the same as squaring each number and adding.

Again, RMS does not give you an indication of the Direction of Power, the reading is always Positive, the Mean or Average setting is not this way! Mean can be Positive, Negative or Zero. Zero means all the Power you send Out to your Load ( DUT ) You get the exact same back again! 1 + -1 = 0...

For some it may seem impossible, but Electromagnetic Induction really does work!

Now I am not perfect I make mistakes! So I urge you to all do your own research on this! Research how to measure the Area under a Curve (  Scope Waveform ) and find out more on this. I did post several very good videos on this!

Remember: Every pixel drawn on your scope screen, it is a Potential Value Recorded. Millions of values measured then recorded of that Potential over Time. All these values, in the Scope Buffer, indicate Instantaneous Power measured over time, this is the X Axis, the values themselves are the Y Axis, Amplitude.

Some time back I was very lucky, a very good friend of mine gave me one on one lessons on how to use a scope. Thanks Gerry!

I hope the knowledge I gained I am now able to pass on to you so you can also pass on.

   Chris

 

P.S: a better code example if you want to play with this:

double Integration = 0.0;

double[] Points = new double[] { 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 8.0, 7.0, 6.0, 5.0, 4.0, 3.0, 2.0, 1.0, 0.0 };

for (int i = 0; i < Points.Length; i++)
    Integration += Math.Pow((Points[i]), 2);

double Mean = Integration / Points.Length;

MessageBox.Show("RMS: " + Math.Sqrt(Mean));

 

Vidura posted this 07 August 2019

A suggestion for a simple and good filter for keeping out interference from our measuring devices. The values of the components are not at all critical, but may need some adaptation for the expected frequencies. Ceramic decoupling  and tantalium caps for the smaller values perform better. The meters could be replaced by a scope as well.

Regards Vidura.

Chris posted this 09 August 2019

My Friends,

I have put what we have covered into a Video:

 

It is important to understand what the numbers are, that's being recorded on the scope. Remember, two wires can only deliver Current in two directions, Positive and Negative. The Negative numbers cancel out the Positive numbers and the Mean is only the total difference.

I hope this helps!

   Chris

Chris posted this 11 August 2019

My Friends,

This video is a bit long and perhaps rambles a bit, but I hope you find it useful anyway:

 

Fighters ZPM is an example of what I am trying to outline! Know the capabilities of your Current Source!

I hope it helps!

   Chris

Jagau posted this 06 September 2019

Hi Chris
an excellent video that I listen until the end

Just a quick note, most of John Bedini's Ing. books carry this mention and I think the same thing.

 

Jagau

 

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Chris posted this 06 September 2019

Hey Jagau,

Thank You! I am glad its useful for you!

Some years back, I did an in-depth study of the way we Humans measure Power. I found that even Electrical Engineers did not have a very good understanding of how Measuring Power properly worked! They get confused and even get it wrong when they are dealing with Non-Linear Loads!

A Non-Linear load, all it means is Power can be sent back to the Source, that's all.

Most EE's do not grasp this concept very well! Even some of the big wigs over on the other forums do not know how to deal with the Non-Linear Load phenomena! Many say use RMS, we have seen, that's just out right wrong if a DC Source is used and we have a Non-Linear Load! Two names in particular come to mind!

Some folks told me, years ago, over on one of the other forums, people are here to help you, they can help with your measurements - That's outright wrong, as they themselves don't know how to measure! See for yourselves: Accurate Measurements on pulsed system's harder than you think.

Even now, Tinman still does not know how to take proper DC measurements, still using RMS measurements with a Non-Linear Load, getting the entire thing wrong! The evidence is here:

 

I hope everyone can see, why its so important to know some of these simple things! Things that the Trolls would be happy for us to stay in the dark about!

Light Up The Darkness!

   Chris

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Jagau posted this 06 September 2019

In the system of which I am more familiar "RF measurement"

it is the mean and the peak power measurement which are important

the RMS is not to use it is mainly to use for more linear circuits.

i agree with you


Jagau

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getreal156 posted this 06 September 2019

Hi Cris and/or others,

For me it also is very confusing and I would love to learn more about this topic. 
Is there a source of information that you can recommend regarding non-linear power measurements?

 

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Chris posted this 06 September 2019

Hey GR,

One source, not really, a study is required, reference and then Cross-Reference is required.

https://www.sciencedirect.com/topics/engineering/non-linear-load

https://www.academia.edu/2072975/Design_of_a_Power_Factor_Measurement_System_for_Nonlinear_Load

and sort of carry on from there.

   Chris

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Jagau posted this 06 September 2019

One of the best video I could recommend is this one

 


Subsequently in his site there are other video on resonance measurements, but starts with this one


Jagau

getreal156 posted this 06 September 2019

Great. Thanks a lot Jagau and Cris

As I am progressing with my experiments it is about time I learn more about it.

 

Chris posted this 06 September 2019

@All Readers,

I think it is important to re-emphasise, there is a time and a place for RMS and also Mean measurements - We need to know when this time is.

  • RMS typically used for an Alternating Current Source.
  • Mean typically used with Direct Current Source. 

The Load, Linear or Non-Linear must be realised. There is a time and a place for each measurement system, and this is what I am trying to explain, how to identify the need for which System.

Its necessary to identify the capability of ones Power Source.

Any Current in a direction, or a Frequency, that your Power Source is not capable of supplying must be taken into account.

   Chris

Vidura posted this 09 September 2019

Current shunt resistors:

As there where some doubts about the high frequency capability of some types of current sensing resistors I will post this suggestion, i use this sometimes as a cheap and very accurate option:  1.6 mm diameter of 308 grade stainless steel welding rods have a resistance of 0.343 ohm per meter of length. You can make a 0.1 ohm precision shunt using a length of 291mm, and if you bend it in a u-shape nearly all parasitic inductance will be cancelled due to opposing magnetic fields . ( like Atti shown in his ZPM replication video). 

Vidura

Fighter posted this 09 September 2019

... or something like this ?...

They are 10A/75mV shunts and I intend to use them for real-time and permanent measuring system on ZPM's input and output.

I will try to use them with some analog ampere-meters, the only problem is calibrating this system to make sure the measurements are accurate all the time in any conditions...

Vidura posted this 09 September 2019

Hey Fighter, Yes this shunts are also ok, the stripe shape has very little inductance , a drawback might be the small resistance, depending of course on the measured current., This one will have a voltage drop of 7.5mV @1A. You can test them with DC, although they are factory calibrated. For practical reasons and easy reading without calculations it is recommended to use values like 0.1 ohm,(100mv @1A) or 1ohm (1v@1A)for smaller current values. Vidura.

cd_sharp posted this 09 September 2019

Hey, guys, testing the shunt 15FR250E:

The results at 1000Hz:

The ringing is there and prevents me to use the shunts for my current experiments. I'll continue without them until I grab another model.

"It's just the knowledge of the coils and how they interact with each other" (Steven Mark)

Chris posted this 09 September 2019

Well, CD, this is odd!

I am going take a guess and say bad Mosfet, perhaps stray capacitance on the Gate? You truly should not be seeing this, even with wire wound resistors!

Testing both Resistors, do you get the same results?

To me, this just does not look like the Resistors are causing all this noise! It is coming from somewhere else, perhaps even a bad connection in the breadboard?

Upwards of 3 to 10 MHz you might see noise like this, but not this low! 1KHz!

   Chris

Fighter posted this 10 September 2019

I would suggest to replace all the inputs and outputs of the device plus the connection from the signal generator to the MOSFET driver with thicker multifilar wire like I use (you can see it in my photos).

Links:

Don't forget all those coil wires I see intersecting each other are producing high-frequency and powerful enough magnetic fields interfering with each other. That could be the source of the ringings, those coil wires are forming themselves small coils interacting with each other.

The only ringings should come from the device itself.

Just my opinion.

Jagau posted this 10 September 2019

it is a very good idea to use gate series resistors of 1K to 10K.

 This is especially important if the Gate signal comes from another circuit board. 

 If a MOSFET could be left floating then use a pull down resistor (100K to 1M is generally ok) from Gate to Source.

you will avoid many problems like this one.

Jagau

solarlab posted this 10 September 2019

Hi CD Sharp,

** Jagua's more than likely correct. **

Might be MOSFET jitter or oscillation due to Gate bounce or noise - the MOSFET is being turned on - off rapidly due to gate trigger threshold being exceeded (noise - probably created by feed-back from the drain - source switching side). 

Refer to some FET gate driver application notes for details.

JMHO of course... [but, I'd bet that's what it is wink !]

SL

 

Chris posted this 10 September 2019

Hey CD,

If I may remind you of our thread: On and Off, Conduction in a Mosfet

We looked at properly switching a Mosfet. This should help greatly with your problem.

I hope this helps!

   Chris

Vidura posted this 10 September 2019

Hello All
Here I will show you how you can make a low cost precision shunt resistor 0.1 ohm made from a 1.6mm 308 grade stainless steel welding rod. First cut a length of 299mm of the rod, 291 mm corresponding to 0.1 ohm resistance, plus 4mm each side for the screw connectors:


Then wrap several turns of a uninsulated thin copper wire over the 4mm reserved for the connector on each side. This is very important, because if only a small area of the resistive rod is touching the connector, the resistance can increase notably and lead to erroneous results.


Then bend the rod in the centre exactly to get a U shape like this:
And finally mount it tightly on a screw connector :

 

Vidura posted this 10 September 2019

I have made a test of the simple circuit suggested by Chris, and want to remark a couple if things: in any circuit where a switch abruptly is turned on and off there will occur transient spikes, the magnitude depending on parameters like the parasitic inductance and capacitance , voltage , current and frequency. Note also that incandescent lightbulbs have a spired filament, which at high frequencies will have considerable inductance, and high power Leds have a lot of parasitic capacitance. One thing I noted , and can not be explained convincedly with the above mentioned influence, is that the shorter the duty cycle becomes the higher the switching transient spikes. I would guess that the ether environment is stroked harder by very short pulses, but this will be subject of another topic. here the video:

Vidura

 

Atti posted this 10 September 2019

Vidura. Szép munka .

CD. Unfortunately, I have a similar problem.

Chris posted this 11 September 2019

Hey Guys,

+1 Nice Work Vidura! Yes spikes are inevitable, as you say parasitic Inductance and Capacitance is always going to be present, but CD's case is extreme  - Nice work Vidura, thanks for sharing!

   Chris

Chris posted this 11 September 2019

My Friends,

For the historical record, we have some conversation over on: Current measuring using non-inductive resistors

This is so we can keep track of posts that flip flop between threads.

   Chris

Vidura posted this 12 September 2019

Hello Friends,
here i will post about an odd result when i was measuring the signal current feeding the opt isolated driver of the Power Switch Modules. In the video you can see the comparison when using the PWM module and then the SG. The scope probes are connected for voltage ch1 (5V/div) and current across a 1 ohm resistor ch2 (10mV/div). the frequency is 30khz  50% duty cycle in both signal sources. Here is the Video:

If someone can check if other SGs also show the same effect would be helpful.

Regards VIDURA.

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Vidura posted this 08 October 2019

Hello Friends, I Wang to present here a simple test i did , maybe anyone can help to verify if we can trast the LCR measurements, or if this results can be bached up with calculations. I took a lenght of wire 12 meters and connected the inductance meter first with the extended wire:

reading 19,7 uH

then with 75 turns on a plastic former, in all tests the same wirelenght:

the coil is extended over 20cm lenght, reading:90uH

now the lenght is reduced to 4cm:

reading 233uH

the lenght is further reduced:

Reading 356uH

now the last on a smaller former with 145 turns in 6 layers:

Reading :452 uH

I did this tests just out of curiousity, but now i have some doubts on the measurements, or what formulas would mach this results,

regards Vidura 

Jagau posted this 08 October 2019

 Hello Vidura

may be an answer to your question with exemple,

look at page 56 of the pdf published recently:

 

 The resulting inductance of a single layer powdered iron toroid can not be precisely predicted due to the effect of leakage inductance, (uncoupled flux). The further apart the turns are, the lower the resulting inductance will be due to reduced flux linkage between turns

 


Jagau

Vidura posted this 08 October 2019

Thanks Jagau, This helps, for air coils it seems to apply also. Vidura

Jagau posted this 08 October 2019

Yes indeed Vidura

it is still a very good question that I had already asked and if it can help. I have read a lot of interesting things here.
I believe in this forum we can make good exchanges of ideas between each member.

I like this forum.


Jagau

cd_sharp posted this 08 October 2019

Guys, Inductance depends also on shape and for solenoids it depends on the length. A more valuable thing for us could be ampere-turns.

"It's just the knowledge of the coils and how they interact with each other" (Steven Mark)

Atti posted this 08 October 2019

Hi everyone.

For measuring Vidura inductance.

We can see that there is a short circuit between two identical coils
after insertion of iron, the inductance of one of the coils increases.
The magnetic field closure of the coils will be shorter.
They will also be more independent.
Thus, a distinction is made between the flux closing in the iron and the flux of the coil.

If it is no longer able to close in iron (due to saturation), it will close in the air. Or iron in between the two rolls.

Vidura posted this 15 December 2019

Hi Friends Some thoughts about interferences and noise. Certainly All who do experiments can observe this phenomenon in some cases. How does this impact on measurements? As you might know i don't own a DSO, and my old ctr scope don't have math functions to make measurements of complex wave forms, so I can only use my common sense to evaluate the influence of interference, ringing and so. We can have the case of a "real" ringing in a setup or device, which would of course display actual voltage and current on a scope, and count as actual power. If this power can actually be used to drive a load is another question. But there's also another case, where interference appears in the measurement device, meters or scope, not displaying the actual behaviour of the DUT. I have many times observed that all kinds of digital meters became practical useless, due to interference. Of course a DSO should be mostly immune to this as it is intended bas precision instrument. I have noted that this interferences are special notable when we have devices which develope standing waves, or with partially saturated cores, shorted coils(also half cycle with diode), and hi voltage Oscillating E fields. In a conclusion of my experiences the analogue meters are the most trustworthy ( not the multimeters, the simple versions). It is a good idea to put them in series to the PS , so you always have a comparison and will nota mayor deviations immediately. For the moment I believe that a backlooped device is the best proof to be AU. Regards Vidura.

Atti posted this 15 December 2019

Hey Vidura.

You touched the point again.
I share the view that digital meters should only be used for orientation. Or DSO.
If there is something strange, you have to think about the possibility of moving on. Or why the situation happened.
But the exact definition requires the ratio of dc input to dc output.
No more accurate than that.

It is possible to deceive others, to mislead others.
But if I mislead myself, then something is wrong.
This can or may not be accepted.
The point does not change.
I think.



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Chris posted this 16 December 2019

My Friends,

Vidura has provided some very important insight! As has Atti!

Complex Signals are a problem for many Instruments - However, an Oscilloscope is designed to measure these signals. Of course, that's the entire design specification for the Oscilloscope.

We should expect from every single Oscilloscope: If it can be drawn on the screen it can be measured.

However, this is not always the case!

We should, as Atti pointed out, try to aim for a DC to DC Input to Output measurement! Thus smoothing out the complex Waveform we might be missing for accurate Scope Measurements.

If there is real power there, then it should be able to fill a Capacitor, then power a Load.

I want to share some helpful videos I shared on Tier II:

 

Both very good videos and help to  understand how the Scope takes a measurement.

The Oscilloscope is by far the most advanced Instrument we have ever created to measure waveform's!

We Should not, we can not discard it as one of the most useful tools in our arsenal! If we are going to do this, we only need to learn how to use these tools properly!

We must not fool ourselves! We must investigate everything and do it properly!

   Chris

Attached Files

Chris posted this 24 December 2019

My Friends,

This post is in regard to recent posts on Fighters Thread, The ZPM, specifically the set of posts after this one.

I see a lot more confusion entering at the moment than is necessary! The introduction of Mains Metered, Low Bandwidth, Watt Meters and Input Power Circuitry was the topic.

No matter what the Circuitry is, in regard to the input Line and the Power Source, and as I said, the less the better, the circuitry will play a role in what occurs on the Input Side, being the Circuitry is Input side Circuitry.

Lets break this down to the most basic possible logic:

 

Your Input power Line:

 

NOTE: This is Conventional Current, we know the opposite actually occurs in the wire. I am showing Conventional Current so as to not confuse people. 

Every single soldier, Charge, that marches up one Wire, must march back down the other Wire. Meaning Current, a bunch of soldiers

From 25V at the Top Left to Ve+, then through the load, not shown, and back again, from Ve-, Right to Left to 0V. Completing the loop. Not a single soldier is lost, with respect to the Circuit!

This is DC, or Direct Current. Directly from one Terminal to the other Terminal. If the Direction of this Direct Current Changes, and this Change is not a function of the Power Supply, supplying the Power, then some or all, or in some cases more soldiers march back the other way.

 

If 100 soldiers march the Circuit, but 10 come back, then we have not used the 100 soldiers, we only use 90 soldiers. We have a 10% return on our Input Power, not all Input Power is Consumed. This concept appears to be very difficult for many EE's to grasp! Current is NOT Power, but Voltage x Current in a DC situation, is.

 

E.G: 

  • 25 Volts x 100 soldiers, or amps = 2500 Watts.
  • BUT, we had 10 soldiers come back!
  • 25 Volts x -10 soldiers = -250 Watts

 

So, we used 2500 + -250 = 2250 watts, 250 watts less than was initially thought!

 

IMPORTANT: Not a single unit can be lost, with respect to the Circuit, every single unit must pass through R1, the Current Sensing Resistor or CSR, sometimes a Current Viewing Resistor CVR. This means all Current from the Source to the Load, and all Current from the Load to the Source can be observed flowing through this CSR, R1.

IMPORTANT: The Bandwidth of this measurement system is only limited to the Oscilloscope and the Current Sensing Resistor you choose to use.

 

Merry Christmas Everyone!

 

   Chris

Atti posted this 18 January 2020

It annoys the length of the measuring resistor I use. That's why I'm buying a precision resistor. We'll see.

"Four-wire resistor optimized specifically for the small-ohmic range. Separately wired sense connectors avoid measurement error caused by transient resistors. Particularly useful in power electronics."

https://www.conrad.hu/hu/precizios-ellenallas-pbv-01-ohm-447331.html

Chris posted this 19 January 2020

Atti is right!

A precision Resistor will be one of the best investments you can make! Get a 0.1 Ohm Precision Resistor, makes for easy Current Monitoring!

 

A precision Resistor, one with minimal Inductance, ±1% or so is important!

Worth going to have a read of this thread: Current Observation and Measurement

   Chris

Jagau posted this 19 January 2020

Another way to take a voltage measurement anywhere in a circuit. In differential mode with an oscilloscope,

try it out the friends it works very well

only with the 2 channels nothing else.

Jagau

Vidura posted this 12 March 2020

Hello All!

this post in order to make you aware of the unusual behaviour of current shunts with a certain length, when tests are performed ,which involve partially or total core saturation. In some videos titled "the effect of core saturation " I have shown already this strange effects. I was not sure if it was something specific of the analogue scope , but lately I saw the effect on one of CD-sharps videos, on his DSO.

in this experiment he used as current shunt  two metal strip precision resistors series connected. I recently made a test  on a saturable device with this shunt:

and then y changed it for this bundle of 10  1ohm resistors(=0.1ohm):

Under "normal" conditions the stainless steel rod shunt is very accurate, but when a saturated core is present, it showed more than 5x the value of the resistor bundle. So when we are working with this kind of devices, the length of the shunt seems to be a critical factor. I also noticed this readings when I used a current transformer, but I have no data about professional current probes, as I dont have such tools. If someone has these, it would be interesting to make a comparison test , if there are inconsistencies.

Mostly I wanted to post this to avoid you to run in measurement errors, using for example the metal strip resistors, when there is a possibility to reach the saturation area of the core.

Vidura.

 

Chris posted this 12 March 2020

My Friends,

Vidura is right! There are plenty of things that can throw measurements off! Thermal Drift, to Stray Inductance, to a scope probe set incorrectly.

The Measurement Blocks I am selling use Industry Standard 0.1 Ohm accurate to 1% Through Hole Current Sensing Metal Strips, very accurate and very reliable:

These PCB Kits are the product of years of experience, a product of on going reliability. This method is one of the most accurate methods of measuring power that I have every used for the price. Other accurate methods can cost many thousands of dollars, I show in this video just how easy it is to use:

 

See the thread: Measurement Block PCB and Kit on E-Bay for info on how to purchase.

Keep your cords short, wires short and there is be very few problems you need to watch out for! Stray Inductance is one of the worst!

It is always good to test and verify what your'e doing, always calibrate your scope and watch for thermal drift.

Best wishes

   Chris

Chris posted this 26 May 2020

My Friends,

Some mostly constructive debate is occurring here: Partnered Output Coils - Builders Group - Moderated!

Note, there are no real Builders, not like here! The debate is on measurements, this the reason I put this post in this thread. Some posts from the one I linked to on are very beneficial if you wish to brush up on our existing knowledge.

Others, on the other forums have been doing it wrong for a very long time! No wonder they are chasing their tails!

Best wishes, stay safe and well,

   Chris

Chris posted this 25 June 2020

My Friends,

Most of us, here know this already, but because I though they were done so well, I thought I would post them here anyway:

 

I did a similar thing some time back and although it was very useful, its only good to a certain frequency. Ideally, DC Projects are what these are best for!

Best wishes, stay safe and well,

   Chris

cd_sharp posted this 04 August 2020

Hi, everyone

I wish to publicly thank Chris for the wonderful measurements blocks. This is a comparison with my old ones which are 0.2ohms, twice the value, but the amount of noise is way up comparing to the AU measurement blocks:

It's a great tool.

"It's just the knowledge of the coils and how they interact with each other" (Steven Mark)

Chris posted this 04 August 2020

Hey CD,

Thank You My Friend! I have found these simple things extremely useful!

Best wishes, stay safe and well,

   Chris

Chris posted this 30 August 2020

My Friends,

Some so called measurement experts call the old fake news line: "measurement error", in reality, they are mostly wrong and can not correctly and accurately call "measurement error". They just don't have enough data and experience to make this call!

NOTE: Run a Scope Calibration before running important Measurements: Utility -> Down Arrow  -> Self-Cal

Remember: Our Energy Machines are Non-Linear Energy Machines! They need proper protocols!

The following procedure is the basic procedure for the Rigol Oscilloscopes:

On the Output, RMS Measurements should be used. On the Input, Average should be used.

Mean is the same as Average.

Sampling, best to use the default: Normal,  or use: High Res.

Setup the Probe Units, set V and I for the probes. Then hit the Math button, go to Math, set A x B, set operation: On, then set Source A and B to the channels you have set.

Set V and I for the Probe settings. Current on 10x on the scope, and 1x on the probe, for Voltage 10x on the scope and 10x on the probe.

Now go to Measure Button, set Measure all: On, and go to Measure All Source, set Math as the measure ticked.

At this stage, you should have a scope menu and it should be displaying Math in purple. You should have three Scope traces, Chx, Chy, and Math.

Turn on your DUT, and tune, adjust the Time and Division scales to fit all trace data, take measurements, screen shotting the Menu onto a USB Key plugged into your scope by pressing your Print Button. Then upload to the forum, this will give you a complete screen shot of the Scope Display.

Basic rule of thumb, Mean or Average is Forward Power minus Backward Power = Mean used Power. Remember, if 1 Amp + -1 Amp = Zero Amps, so forward Power can be the same as Backward Power, meaning if all your Power comes back to you, then you have used no power!

On the Output, RMS is used, as all Power Out is Used, so no Power is going back to your Input.

 

I have a short video on how to take measurements using the Rigol Oscilloscope.

 

 

Note: I have shown the basic setup for most measurements, using the Aboveunity.com Measurement Block using a 0.1 ohm metal strip resistor.

 

 

Don't let anyone else tell you you are wrong! You must only measure Used Power, Returned Power is not Used Power on the Input, so you MUST use Average and not RMS!

On the Output, You need to use RMS and compare it to the Average!

The procedures on this thread are very important and need to be understood and followed to make Close Approximations!

It is very easy for Experts, to make wild assumptions and for those not skilled in the Art, to become confused, a tactic they rely on to dissuade others, thinking they have it wrong when they do not! Let no one tell you any different especially when they have Zero Real World Experience!

Only Aboveunity.com Members should be trusted in this Field! No one else!

Best wishes, stay safe and well My Friend,

   Chris

baerndorfer posted this 12 September 2020

hi guys, here you can see a measurement from MSO5204

Measurement Problem

you will notice, that the measurement for the pulsewidth is not correct. the device switches between nanoseconds and microseconds for some reason. the cursor measurement is correct.

what i want to point out is, that we should not fully trust our equipment it helps in many situations but only the operator who knows about how measurement is done correctly can derive meaningful theses out of it.

the next scope shot is for entertainment only...

greetings!

Jagau posted this 13 September 2020

Hi baern
Its look like what EEvblog spoke about this rigol model MSO
Known Firmware Bugs / Issues 11 Time base bugs
look here:
https://www.eevblog.com/forum/testgear/review-rigol-mso5000-tests-bugs-questions/
Jagau

Chris posted this 14 September 2020

My Friends,

A simple experiment, lets see if we can take a simple experiment and learn something simple?

 

The Circuit:

 

The Scope Shot:

 

The Results:

The power used, is the Average: 3.06 Watts, but the RMS: 5.17 Watts, Power is a long way off!

Using DC, Switching on the High Side, and measuring the Input Power, going to the Resistor, or Globe, we see a massive difference! A difference that the other Forums have not even switched on to!

2.11 Watts of Error!

I have to say, the professionals that so many people have listened to for so long, over on the other Forums, are so far out of touch its just not funny! They are completely Wrong on nearly every aspect!

I hope all Aboveunity Members can now see why I have tried to tell everyone not to use RMS? When using DC, Switched, RMS is not sufficient to give anywhere near accurate measurements!

You must use Average, or Mean, on the Input!

The smallest Experiment can yeild the most important information!

Best wishes, stay safe and well My Friends,

   Chris

Jagau posted this 14 September 2020

Hi Chris

Analog device a very reputable semiconductor company and their service engineer produced a memo which you confirm Chris.
Read the pdf enclosed as irrefutable proof.

 

It is the average power that produces the correct value, and thus it is average power that has physical significance.

 

Jagau

 

Attached Files

Vidura posted this 17 September 2020

Hello All,

as there has been some uncertainty regarding the current measurements with the scope, I decided to make a series of tests with different shunts and test conditions. The circuit is simple, a low side switch, IRFP460 , a filament bulb 12V 20W, two capacitors on the supply line 10000uF + 100nF. PWM module set at 50% duty cycle.

the analogue Ammeter showed the expected average value of  1/2 peak current in all  the tests:

The first test is made with a wire wound 1 ohm 5 W resistor. I really expected a much worse result with this one, but note that the inductive part isn't significant as the "coil" has only 4mm diameter and 10 mm length, with bigger sizes we can expect more inductance of course. here the scope shots in three different frequency ranges:

above 30khz switching spikes appeared.

@ 100khz  notable ringing and large switching spikes

at 350khz ringing and alteration of duty cycle.

next tests with a boundle of 10 resistors 1 ohm 1%   equivalent  0.1 ohm

less ringing and smaller spikes

at 350 khz  also a lot of distortion and ringing, but I realized that a lot of it is caused by the parasitics of the layout and wires.

I added a 100 nF cap near the shunt and the signals improoved notably:

A selfmade SS rod shunt:

At higher frequencies unsuitable.

metalstripe 0.1 ohm:

conclusion, for the instance non of the tested shunts would give a reliable readings above 150khz, using the math function of a scope. will continue.

Vidura posted this 17 September 2020

A couple of things more: I haven't tested special nonconductive shunt resistors, as I don't have any available, they might be something more accurate . The best performance gave the bundle of precision resistors. For the practical implementation of shunt resistors we should choose the value In proportion to the expected current in the circuit. It has to be taken in account that the power dissipation of the shunt will increase at the square of the current, therefore for major current capabilities, shunts of very low resistance and high wattage will be employed. For example a shunt 0.001Ohm@ 100A will dissipate 10watts , and read 0.1V For more accurate measurement at lower current, the resistance should be increased. A 0.1ohm shunt rated for 10W would be capable up to 10A Reading 1V on the scope. This ratings are for the maximum amount of CONTINUOUS current, with pulsed current the value can exceed, dependent on the duty cycle. For measurement of small current in the mA range a 1ohm resistor could be a good choice, as the higher voltage reading will reduce noise on the scope.to be continued...

Chris posted this 17 September 2020

Hey Vidura,

My Friend, you are exactly correct! Thank You for Sharing!

For very low Resistance ( 0.001 Ohm or lower ), a Op Amp may be required, depending on how much Current the Resistor carries, as the Scope may not be able to accurately measure such low Voltage Drops:

 

NOTE: ADC is Analog to Digital Converter. A Microcontroller uses a ADC to read the Voltage Drop in a Digital Meter.

None of this is hard, if others that are not sure, just follow the advice of those of us, here, that know better and are trying to help.

Selecting a Resistance Value is important for the Range of Currents you expect, just as Vidura has said.

Your Guide is very valuable! Thank You!

Best wishes, stay safe and well My Friends,

   Chris

raivope posted this 17 September 2020

Hi,

For 0.001 ohm shunts, I have built, the op-amp must be chosen with very low offset error to have quality output. Plus and minus supply to op-amp must have good RC filter to avoid ripple noise.

(I used to build amp sensor plus multiplied by voltage we get power and power was forwarded (in range 0..5V) galvanically isolated to output where you can read with ADC or simply with panel meter. Usually I kept 2.5V as a zero centre to measure also negative range.)

Best,

Raivo

Vidura posted this 18 September 2020

Hello Friends,

In this post I will provide a solution for the interference issues shown in the last post. Note that this method is adequate (only) for quantitative measurement, that is for power measurements. It consists in averaging the signal from the shunt (for current) or from other test points (voltage). Note that this method will provide a clean signal, but will not account for the involved powerfactor. Thus it is suitable for resistive loads only. 

Up to frequencies of 50khz we can do it as simple as this:

Also the analogue meters are very simple and trustworthy, if some decoupling capacitors are placed near the DUT.

 

 

In the following Images you can see how I developed a simple filtered circuit to make clean avarage measurements:

at lower frequencies the above circuit works fine.

But when we increase...

so i tried this:

Much better, but not good enough.

next step....

the result, at maximum frequency of the PWM:

the remaining interference comes from the conector of the scopeprobe:

removed the ground clip:

Now it is acceptable. I hope this helps some.

Vidura 

 

 

 

Vidura posted this 19 September 2020

Hello,

In this post I will address another potential issue on measurements , which you won't find likely on any other Forum. On order to establish a really complete and trustworthy measurement protocol we have to be aware of the following effect. It is not explained by conventional EM theory. I have already posted something about it, but can't remember in which thread. It is documented in the videos 

and 

I could observe the effect in the following circuits, it happens when the core goes in the nonlinear region near or beyond saturation:

 The most pronounced in the first one, where the core saturates always beyond a threshold duty cycle. In some cases it occurs only with a very fast switch, and the intensity might vary with various parameters. One most important is the physical length of the shunt, it's material and the distance of test point and scope ground connection. So here I have made a short video related to the effect on measurements:

Some recommendations regarding your measurements specially when in the DUT saturation or nonlinearity are likely: If you find some odd behaviour like currents against blocking diodes, or switches in off state, then check again using a different shunt, eventually carbon resistors, ensure that the scope probe is close to the shunt resistor(test point and ground, both).

Vidura

Chris posted this 2 weeks ago

My Friends,

In our quest to bring easy simple measurement to every person with an Oscilloscope, we have had a few issues that have cropped up, simple issues to fix, but issues one needs to be aware of.

 

Best Practice: It is always best practice to use a Current Sensing Resistor ( CSR some use the term CVR Current Viewing Resistor ) that will have the least possible effect on the Circuit! As if the CSR was not in the Circuit! Remember, you always want to take measurement on the Circuit , which means if you change the Circuit by introducing large Impedances, the Circuit is no longer the same! To take accurate Measurements, the Circuit must be minimally affected by introducing your Measurement Equipment! This is important!

 

Recently, Itsu has done a video on 1 Ohm vs a 0.1 Ohm resistor:

 

For sure, the 0.1 Ohm Resistor is Bad!

Ohmite Resistors are commonly Wire Wound, they say that they are not, or say: "Non-Inductive" but beware, they can go bad very easily!

CD_Sharp has seen this issue before and we have resolved this simply by replacing the Resistor.

This is another reason Equipment should always be Calibrated and Checked! We have not yet seen any issues with the Measurement Block I have shared with you all! The Measurement Block should always give you a solid stable Signal! However, it is wise to Test its accuracy on a regular basis!

 

Where:

  • Green Trace = Clamp on Current Probe.
  • Blue Trace = 0.1 Ohm Current Sensing Resistor.

 

Current Signals should always be the same! If they are not, as in Itsu's case, above image, there is a Problem!

I have left a Message:

 

Best Wishes

   Chris

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Chris posted this 6 days ago

My Friends,

I have decided to post this post here in the Measurements thread also, to help others out.

Itsu has a fresh round of "Surprising" data:

Ref: Itsu's workbench / placeholder.

 

This is an astounding series of statements! It really is!

Every single Engineer on the planet will disagree with Itsu's statement that a 1 Ohm Current Sensing Resistor is Superior!

 

Proving Incorrect

In the following circuits, you can see the Voltage Drop across the Load and the Current Sensing Resistor:

 

You can see, with a 1 Volt Supply, with a 0.5 Ohm Load, we get a greater Voltage Drop across the 1 Ohm Resistor than the Load, this means, more Energy is being wasted in the 1 Ohm Resistor than is being consumed in the Load!

This Circuit, because we introduced the 1 Ohm Resistor is now Mal-Performing by a factor of: 2

This circuit is NOT being measured properly, because we have changed the Circuit by introducing 2x In-Circuit Impedance is not greater than the Load!

 

 

This Circuit, because we introduced the 0.1 Ohm Resistor is now Mal-Performing by a factor of: 0.2, an improvement of 10 times!

Now we can say we have reduced the In Circuit Impedance by 10 Times and also have a Circuit that is MUCH Closer to the actual way the Circuit is supposed to actually work!

It is Best Practice to measure a Circuit, with minimal Introduction of Impedances!

 

Current Sensing Resolution

How does Resolution work?

The Voltage Drop over a Resistor is using the Ohms Law equations to determined Current via: I = V / R

NOTE: Current Sensing Resistors are ideal at specific Ranges of Currents! Beyond those Ranges, they are not adequate and should be replaced with adequate Resistors!

As far as I understand, 50mV per division is Industry Standard Baseline for Noise test. So anything below 50mV per division is not useful for accurate Measurement.

People must think about this! This is important!

If we plot, the Voltage Steps vs the Current we see something that is very important:

 

The deviation between the 1 Ohm Resistor and the 0.1 Ohm Resistor grows linearly, this means, the Error is greater per Voltage Step, on the 1.0 Ohm Resistor! Yes, Error!

For every 50mV step, which is mA if on has the Scope set correctly, is: 10x

What does this mean? Well, we are able to Measure much more finely, we can Measure, 10mA to 1mA, let me show you:

 

There you have it, the Resolution is much greater on the 0.1 Ohm Resistor than the 1 Ohm Resistor, we lost a whopping: 45mA compared to the 0.1 Ohm Resistor: 4.5mA. So you see here, we have 10 times the Resolution with a 0.1 Ohm Resistor! 10 Times More Accurate! Simply: 0.1 Ohms is 10x the Resolution of a 1.0 Ohms Resistor!

 

A Resistor is a Resistor is a Resistor

NO! You need to carefully select a Resistor to do the Job! The exact same waveform should always be available every single time between the Resistors, except for the above stated Resolution issues! If the waveform is in any way distorted, throw away the Current Sensing Resistor and get a Good One!

We have very carefully selected the 0.1 Ohm 1% Tolerance, Metal Strip Through Hole Resistor to accurately give measurements in median Current Ranges! Others can try to find fault all they like, but really, they just show how un-educated they are about such things!

A good Current Sensing Resistor should be nothing more than a piece of Wire of Known Impedance. Remember, keep all wire lengths short as possible! Always!

 

 

Conclusion

I hope you can see, why we are Light Years ahead of the other Forums! This, what I have shown here is simple stuff and they should know this stuff!

It is Industry Standard to use Very Low Resistance Current Sensing Resistors! This is very well known! Extremely Low Resistances, even as low as 0.0001 Ohms, or 100 μOhms.

 

I recommend all to do their own research and even check and double check what I say!

 

Rigol DP832 Precision Power Supply Current Shunt Resistor: 0.02 Ohms 1% Tollerance

 

The top of the line Keysight Current Probe uses a 0.1 Ohm Sensing Resistor! Thanks Jagau for the link!

Don't let yourself be led up the Garden Path, is easy, if you let this happen!

NOTE: This group of people that have been calling: "Measurement Error", on your machines for decades! Do you see why I have done what I have done? They are not qualified, or well enough educated to make Judgment on Others Work!

Stick to Facts, Logic and what Makes Sense!

Best Wishes,

   Chris

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Chris posted this 5 days ago

My Friends,

It is true, some totally ridiculous statements are being made over on one of the Other Forums. You know where!

I want to stress again, use: Common Sense

Take a length of Wire, 3 Centimeters, it has an inductance of 300 μH, we remove 2 Centimeters of Wire and replace this length with a Current Sensing Resistor, or Current Shunt, it has an inductance of 200 μH, which just happens to still give us 300 μH in Total.

Are we Better off or Worse off?

Neither! We have the exact same Inductance!

Some people absolutely Grasp at Imaginary Straws! Current Sensing Resistors come in all Shapes and Sizes, with many different Inductances and Resistances! Here are just a few examples:

 

If someone is Un-Educated enough to choose a Current Sensing Resistor that has a large Inductance in Applications at High Frequencies, then this is a mistake!

However, as already pointed out, if your Current Sensing Resistor has no more Inductance than a piece of Wire of the Same length, then you are ONLY going to have a problem if you have not followed advice already given, which is: Keep all Wire Lengths as Short as Possible.

It is a total joke, just stupidity, to make any wild claims of:

  • In Accuracy
  • Current Waveform Difference
  • Bad Data in General

 

Unless one has deliberately chosen bad Current Sensing Equipment! E.G: Wire Wound Resistor or similar!

It is obvious, the Current in a Circuit, MUST always be the same in the Circuit, the Entire Circuit, according to Kirchhoff's Current Law:

We simply can not read different Currents at each of the different Meters, or Nodes! That is, unless the Element itself is creating a Change in the Current! E.G: An Active Element!

 

Those people, out there, should know this already, unless they are Learning Impaired! Alas, they don't! And that's why you should not listen to them!

It simply can not be said, a Sense Resistor with the same Inductance as a piece of Wire the same Length will be any more problematic than the piece of Wire itself! That's just not true! Period!

The Comparison being made by these people is ridiculous:

 

All people with 5c of Common-Sense is not going to use L1 as a Current Sensing Resistor!

This Current Sensing Resistor:

 

Has: < 3nH that's less than 3 Nano Henry's of Inductance. Less than some pieces of Wire, the same length! See Datasheet Below.

We have covered this many times:

 

Again, do stupid un-educated things, expect stupid un-educated Results!

Best Wishes,

   Chris

Attached Files

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raivope posted this 10 hours ago

Hi co-creators!

I found an amazing solution for current measurement by testing different shunts, resistors(10x in parallel), current clamp.

Lets call it HF shunt (above) and the bottom one is 200kHz bandwidth clamp (realistically you can go to 20kHz where you start having a phase lag).

This HF shunt is virtually noise free and totally free from phase lag - tested up to 60MHz.

However, it will have some anomalous amplitude rise near 2MHz, so I would certify this shunt to have 1MHz bandwidth.

Only 3 pieces needed:
Oscilloscope Probe, Passive, 150 MHz (run at 1:1) -  https://uk.farnell.com/testec/lf312/probe-oscilloscope-low-frequency/dp/220619

* BNC Coaxial, Straight Jack, 50 ohm  - https://uk.farnell.com/amphenol/b6251c1-nt3g-50/rf-coaxial-bnc-straight-jack-50ohm/dp/1111295

Current Sense Resistor, 0.1 ohm, PWR220T-35 Series, 35 W, Thick Film, TO-220 - https://uk.farnell.com/bourns/pwr220t-35-r100f/resistor-power-0-1r-0-01-35w/dp/2101746

This Oscilloscope probe had special connector for BNC.

Here you can see the noise difference of this wire shunt you use and HF shunt:

My top:

  • HF shunt - 1MHz
  • thru the hole wire shunt - 200kHz - the same as 10x 1ohm metal-foil resistors in parallel (less noise than wire shunt)
  • CP-05A current clamp - 20kHz (good point to have it is low noise and galvanic isolation)

Best wishes,

Raivo

 

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