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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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

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 

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

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

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 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

 

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 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.

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

 

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

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

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.

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

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

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

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.

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

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

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

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.

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

 

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.

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

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 04 August 2020

Hey CD,

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

Best wishes, stay safe and well,

   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

raivope posted this 26 November 2020

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

 

Chris posted this 27 October 2021

My Friends,

It seems Aboveunity.com's World Leading Measurement Techniques have now, all of a sudden, been adopted by others:

Ref: Itsu's "state of the art" nano-pulser

 

Those that used to try to call fault to Aboveunity.com's technique! Now use this very same Technique!

Isn't that Ironic! My how things have changed! Seems they have managed to pickup on Industry Standard Techniques, the ones we learned many years before!

If Itsu was measuring "Power", can anyone see a problem that Itsu would have in doing so? It is easy to spot!

Best Wishes and great to see the evolution of those that used to pick others work to pieces! See Here for details!

   Chris

Chris posted this 14 July 2022

My Friends,

This thread covers in great detail, why we should not be taking RMS Measurements on a DC Input Power! I want to re-iterate this fact, because we have had a situation on Jagau's Thread, where RMS was shown on each Channel.

Exactly as Jagau said:

 

 

It seems misunderstood that when we are in the presence of different waveforms the way of calculation is different 

Ref: Jagau's Advice for Measurement

 

RMS Can not be used because all power on the line is counted as Input Power, active Power, used Power and this can be very different from the actual situation!

 

Why is this important? Watch this video:

 

Here is an example of why it can be very different: Using a Non-Linear Load on a DC Power Source

 

EG:

  • 1.28 Watts RMS ⇐ Includes Negative Power: V x -! = -P
  • 0.0957 Watt's Average ⇐ Only the Forward Power, Active or Used Power. If Negative, more Power is going back to the DC Source!

 

Power Flow in a Four Quadrant Argand Diagram:

 

Its worth studding the Power Flow in the Four Quadrant Argand Diagram to see how this works. Again, Positive Voltage x Negative Current = Negative Power, Generator Mode!

Again, already covered, the V x I Power, if one does the math, can work out to be Negative, and RMS voids this Power! RMS Includes this power as Used Power when it is not!

Know what your Input is doing, and then you can make so much more progress! Ignore others that do not abide by Industry Standard Protocol! 

We have the Best Measurement Protocols in the World! We are Accurate!

Bad or misleading procedure can cost you the Success you work so hard for, so learn Correct and Accurate Procedure, please!

Best Wishes,

   Chris

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,

Accurate Measurements can be obtained using the circuit here.

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

   Chris

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 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.

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.

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

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 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

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...

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.

Atti posted this 10 September 2019

Vidura. Szép munka .

CD. Unfortunately, I have a similar problem.

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 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

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Ere many generations pass, our machinery will be driven by a power obtainable at any point of the universe. This idea is not novel. Men have been led to it long ago by instinct or reason. It has been expressed in many ways, and in many places, in the history of old and new. We find it in the delightful myth of Antheus, who drives power from the earth; we find it among the subtle speculations of one of your splendid mathematicians, and in many hints and statements of thinkers of the present time. Throughout space there is energy. Is this energy static or kinetic? If static, our hopes are in vain; if kinetic - and this we know it is for certain - then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature.

Experiments With Alternate Currents Of High Potential And High Frequency (February 1892).

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