Lawrence Tseung sent a Prototype to test... any comments?

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Author Topic: Lawrence Tseung sent a Prototype to test... any comments? (Read 330390 times)

Harvey	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #500 on: 2011-02-03, 04:27:01 »
Group: Guest	Quote from: ltseung888 on 2011-02-03, 02:54:36 To make the debate meaningful, I shall take the following positions . . . 2. For a generalize waveform, the rms value MUST be used. . . . I think we are getting close to establishing the topic and the stance of each participant. Debate Topic: "What method of computation should be applied to a Power Waveform Trace to obtain the Average Power of the sample set under consideration?" Poynt99: Is your stance that the MEAN computation must be used? Lawrence: Is your stance that the RMS computation must be used? If so, then when the facility is made available I will set up the debate thread along with a separate audience thread where the matter can be discussed. Harvey

poynt99	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #501 on: 2011-02-03, 04:48:55 »
Group: Administrator Hero Member Posts: 3208 It's not as complicated as it may seem...	Regarding the question, yes. My stance is for MEAN. I have set up a new "Technical Debates" board here, where you are the moderator Harvey. .99 --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

Harvey	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #502 on: 2011-02-03, 05:13:08 »
Group: Guest	Ok, the debate thread is setup there along with an audience area for comments on the debate. May good things come from this interchange of knowledge that everyone can benefit from

MileHigh	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #503 on: 2011-02-03, 05:18:59 »
Group: Guest	Good that there will be debate thread. The confusion lies in that when you look at voltage or current, the power associated with these parameters is proportional to the square of the measurement. That's why you make RMS measurements on AC voltage-alone or current-alone waveforms to "rationalize" them down to DC equivalents. It's a way of giving you a measure of the true power capability inherent in an AC voltage or current waveform. Alternatively, voltage times current is in itself a measurement that is the product of two variables and is therefore inherently "squared." When it comes to a "power waveform," that is an abstraction derived from two other real-world variables. The power waveform already factors in the "squared" factor associated with the voltage and current waveforms. Therefore it makes no sense at all to "square power" and then take the mean value of that and then calculate the square root. The only thing that you have to do is average out the power over an entire periodic cycle. When you want to calculate energy over a cycle, you integrate the power waveform over that cycle to get your energy calculation. You do not integrate over the square of the power waveform and then take the square root. Again, that makes no sense. MileHigh

poynt99	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #504 on: 2011-02-03, 05:28:03 »
Group: Administrator Hero Member Posts: 3208 It's not as complicated as it may seem...	Quote from: Harvey on 2011-02-02, 07:34:51 Hi All, Before an actual debate thread is started regarding measurement methods it may be good to review certain terms to lay the ground work for mutual understanding. Q. What does 'mean' mean when used on a scope? A. It is the Arithmetical Mean of the selected train or cycle. This is often referred to as the Average Q. What is the Formula for Average Power (Mean Power) in an AC waveform? A. (Also See: http://en.wikipedia.org/wiki/Audio_power#Power_calculations ) Q. Is there a formula for calculating the RMS value of a sawtooth wave like those shown in some of the screen shots here? A. Yes, if the period and amplitude are consistent: http://en.wikipedia.org/wiki/Root_mean_square#RMS_of_common_waveforms Q. Is there any solid way to compare power between two stages of a circuit when the waveforms are wildly diverse in amplitude, frequency and envelope? A. Yes. Certain scopes offer an AREA selection that will return Volt-Seconds of a particular wave form. When applied to the power traces for the two stages an easy comparison can be made that very accurately provides the ratio between the two stages. For an example see page 162 in this manual http://www.tequipment.net/pdf/Tektronix/DPO3000_UM.pdf Q. Can the ground system of two different scopes inject energy into a DUT? A. Yes. Consider a situation where two scopes are plugged into different receptacles only a few feet apart. The ground wire for each is routed next to the other two current carrying wires in the wall for those few feet. Current flowing in those other wires will induce current in the ground wire along that path. Now consider that one of the scopes is connected to the input stage at the battery ground and the other is connected to the output stage (isolated by the toroid). We now have created a short circuit between the reference lead at battery negative and the reference lead at the output winding and we are pumping energy into that wire which in turn will drive the output transformer from the output side and store energy in its core. So it is important that short circuits of this sort are allowed for the DUT and that any grounds for connected test equipment are secured as close to each other as possible. I think it is great to have so many persons assembled in one place to share their knowledge and experience. Unfortunately I cannot claim that all of my knowledge is accurate and correct, so it is practically guaranteed that I will make mistakes and errors. So when you see them, please feel free to correct them Cheers! Harvey Thank you for the helpful links and info Harvey. Your knowledge, creativity, and aptitude for teaching will also be a boon for OUR. We all slip up from time to time, and I know you'll be there to catch our falls too. Welcome to the forum Harvey, and thanks for taking on the Technical Debates Moderator job. .99 --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

poynt99	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #505 on: 2011-02-03, 18:33:49 »
Group: Administrator Hero Member Posts: 3208 It's not as complicated as it may seem...	While we wait for a rebuttal from Lawrence in the debate thread, I am off today, and have already wound my toroid transformer. I'll be posting pictures and preliminary scope shots (1x 100MHz scope at the moment) today/tonight, so stay tuned .99 --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

ltseung888	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #506 on: 2011-02-05, 10:32:56 »
Group: Guest	Quote from: poynt99 on 2011-02-03, 18:33:49 While we wait for a rebuttal from Lawrence in the debate thread, I am off today, and have already wound my toroid transformer. I'll be posting pictures and preliminary scope shots (1x 100MHz scope at the moment) today/tonight, so stay tuned .99 Looking forward to that and seeing the mean value.

GibbsHelmholtz	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #507 on: 2011-02-05, 13:18:40 »
Group: Guest	Quote from: ltseung888 on 2011-02-05, 10:32:56 Looking forward to that and seeing the mean value. btw mr. Tseung, I think what you were looking for earlier is (l P1l + l P2l + l P3l . . . l Pnl) / n

poynt99	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #508 on: 2011-02-05, 13:24:52 »
Group: Administrator Hero Member Posts: 3208 It's not as complicated as it may seem...	Quote from: ltseung888 on 2011-02-05, 10:32:56 Looking forward to that and seeing the mean value. Indeed, you will I suspect we might also be seeing some very different numbers from the professor now. .99 --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

ltseung888	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #509 on: 2011-02-05, 15:53:11 »
Group: Guest	Quote from: GibbsHelmholtz on 2011-02-05, 13:18:40 btw mr. Tseung, I think what you were looking for earlier is (l P1l + l P2l + l P3l . . . l Pnl) / n Well put. But that was in the past. We continue to move forward. The results and screen shots from poynt99 will tell us much more. Especially the mean.

poynt99	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #510 on: 2011-02-05, 17:53:18 »
Group: Administrator Hero Member Posts: 3208 It's not as complicated as it may seem...	Lawrence, did you find what you thought were favorable results, at any particular frequency range? What was the lowest frequency you or some other experimenters have used? .99 --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

GibbsHelmholtz	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #511 on: 2011-02-06, 00:57:15 »
Group: Guest	Quote from: ltseung888 on 2011-02-05, 15:53:11 Well put. But that was in the past. We continue to move forward. The results and screen shots from poynt99 will tell us much more. Especially the mean. You are a scary man and can only compares to Rosemary.

ltseung888	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #512 on: 2011-02-06, 01:37:55 »
Group: Guest	If you look at reply 22 in the participant debate thread, from Poynit99: Quote What Harvey is trying to convey, is that VRMS * IRMS = PAVE = MEAN[v(t) * i(t)], and he is correct. We have been using VRMS * IRMS and Vpp * Ipp for our estimation since July 2010 and that was renamed Tseung FLEET Comparison Index under the request of Poynt99. If VRMS * IRMS = PAVE was the correct equation to use, we accidentally used it for months now. It would be interesting to see the results from Poynt99. I am even more confident in helping him to tune a device with COP > 1!

poynt99	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #513 on: 2011-02-06, 02:08:28 »
Group: Administrator Hero Member Posts: 3208 It's not as complicated as it may seem...	Quote from: ltseung888 on 2011-02-06, 01:37:55 If you look at reply 22 in the participant debate thread, from Poynit99: We have been using VRMS * IRMS and Vpp * Ipp for our estimation since July 2010 and that was renamed Tseung FLEET Comparison Index under the request of Poynt99. If VRMS * IRMS = PAVE was the correct equation to use, we accidentally used it for months now. It would be interesting to see the results from Poynt99. I am even more confident in helping him to tune a device with COP > 1! That method is only valid for 0-phase circuits Lawrence. The phase relationship is not accounted for that way, and it will yield incorrect results in cases where there is phase shift between the voltage and current. Let's stick to the p(t) method, sound good? .99 --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

ltseung888	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #514 on: 2011-02-09, 18:31:55 »
Group: Guest	The prototype with high Tseung FLEET Comparison Index is being delivered by Fed Ex to Poynt99. He should receive it later this afternoon (Feb 9). The latest is tomorrow. The prototype should be tested as shipped. That would give a quick comparison between his oscilloscope and the ATTEN oscilloscope used in Hong Kong. That prototype should be used for testing and discussion purposes. It has a higher Index value than that sent to Physics Society in Beijing. Poynt99 should also be receiving a components package via Post Office Mail. He should Keep the prototype as shipped and build another prototype to his liking. The fun begins. Lawrence ------------------------ Lawrence Tseung sent a Prototype to test... any comments? Prototype on Feb 7b.JPG (67.53 kB, 960x720 - viewed 931 times.)

poynt99	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #515 on: 2011-02-09, 19:21:20 »
Group: Administrator Hero Member Posts: 3208 It's not as complicated as it may seem...	Sounds good. Will do Lawrence. .99 --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

PhysicsProf	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #516 on: 2011-02-17, 21:24:40 »
Group: Professor Hero Member Posts: 2994	Yesterday, I traveled to the University and used the Tektronix 3032 there. (I may use it, not bring it to my home, a distance of about 70 miles away. We drove home through a blizzard last night... but made it safely.) I decided to post the results, whatever they turned out to be. Prototype A was sent to me by Lawrence some time ago. I have preserved his soldered-up JT circuit (with transistor) -- except that I cut a wire to the LED here. On the output circuit, I replaced the two resistors (10 and 100 ohms) with a single 1 ohm resistor, keeping his white LED there. Below are the results, showing the Power waveform for both input and output in Red -- and letting the Tek 3032 do the Mean calculation for many cycles. Also shown are the RMS voltages for the input- and output-circuit voltages and for the 1-ohm resistor leading to each of these circuits, which will be of interest to some. ------------------------ ProtoAinMany.bmp (301.05 kB - downloaded 349 times.) ProtoAoutVeryManyOUR.bmp (301.05 kB - downloaded 329 times.)

PhysicsProf	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #517 on: 2011-02-17, 21:37:24 »
Group: Professor Hero Member Posts: 2994	The Math waveform is channel 1 TIMES channel 2, that is, VI = P since 1-ohm resistors are used in both input and output (one for input, one for output). Using the mean Power calculated over many cycles, we can evaluate the COP: Prototype A, Poutmean = 61.62 mVV Pinmean = 106.2 mVV, so that the COP is Pin/Pout = 0.58 Now, let's take a look at the VRMS and IRMS values also given by the Tek 3032 -- which RMS values have been the subject of debate here at OUR: Vrmsout I rmsout = 2.92V * 31.5 mV = 92.0 mVV Vrmsin * I rmsin = 1.43V * 110 mV = 157.3 mVV So that the "FLEET Index" as defined in this thread becomes 92.0/157.3 = 0.58 -- which agrees very well with the COP evaluated above by a different method (using the Mean Power values). So I ask you -- is this agreement just a coincidence?

PhysicsProf	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #518 on: 2011-02-18, 06:45:04 »
Group: Professor Hero Member Posts: 2994	Hmmm... This is an important question. Hope I haven't stumped you guys: Quote So that the "FLEET Index" as defined in this thread becomes 92.0/157.3 = 0.58 -- which agrees very well with the COP [of 0.58 also] evaluated above by a different method (using the Mean Power values). So I ask you -- is this agreement just a coincidence?

Harvey	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #519 on: 2011-02-18, 09:50:37 »
Group: Guest	Hi PhysicsProf, That is an interesting thing, but what is missing is the average phase angle which could be determined in post by the following: Mean Power / (V_rms * I_rms) = Cos(θ) or θ = InvCos(Mean Power / (V_rms * I_rms). Pavg = V_rms * I_rms * Cos (θ) (the formula in my prior post is for purely resistive circuits only where θ = 0) So for POUT_mean = 61.62 mVV (or mW) we get θ = InvCos(0.06162 / (2.92 * 0.0315)) = 47.69° And for PIN_mean = 106.2 mVV (or mW) we get θ = InvCos(0.1062 / (1.43 * .110)) = 47.53° So there is some phase differential between the input and the output by about 0.16°. If the scope were able to give you this average phase angle, then you would have arrived at the same values as the mean. I would like to point out that these are 'effective' phase angles that allow us to treat the signal as a sinusoid in these calculations. The more complex the waveform, the more difficult it is to process in this way. But looking at the actual factors involved, we see that Cos(47.69) is 0.673 and Cos(47.53) is 0.675 so the differential of 0.675 / 0.673 is .0029 away from 1 and this falls below your 2 digit rounding. So essentially excluding your phase angle in this case was the same as having a factor of 1. I think that is why it came so close to being the same thing. Something I wanted to try, and did not get a chance yet, was to compare Lawrence's index differences to actual average power differences. In other words, if Lawrence was doing the math wrong, he was doing it wrong for both the input and the output so both were inflated or deflated by the same algorithm and that may mean that the ratios held. Just a thought. Also, do you know if his scopes output any data? If he has the raw data then we could have a look at that and see what it shows. Harvey

GibbsHelmholtz	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #520 on: 2011-02-18, 14:34:19 »
Group: Guest	It doesn't make sense to me that the phase angle of the primary is different than the phase angle of the secondary although the overal circuit phase angle can change significantly with frequency. In another word, they can change, but both must have the same phase. In this case, it's easy to prove. Ri/Ai = Ro/Ao ===> Ri/Ro = Ai/Ao R= real power i = input o = output A = apparent power Yes, they were eating apples and oranges and try to convinced the world which one taste better. Thank you professor for your trip.

humbugger	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #521 on: 2011-02-18, 14:59:21 »
Group: Guest	Quote from: Harvey on 2011-02-18, 09:50:37 Hi PhysicsProf, That is an interesting thing, but what is missing is the average phase angle which could be determined in post by the following: Mean Power / (V_rms * I_rms) = Cos(θ) or θ = InvCos(Mean Power / (V_rms * I_rms). Pavg = V_rms * I_rms * Cos (θ) (the formula in my prior post is for purely resistive circuits only where θ = 0) So for POUT_mean = 61.62 mVV (or mW) we get θ = InvCos(0.06162 / (2.92 * 0.0315)) = 47.69° And for PIN_mean = 106.2 mVV (or mW) we get θ = InvCos(0.1062 / (1.43 * .110)) = 47.53° So there is some phase differential between the input and the output by about 0.16°. If the scope were able to give you this average phase angle, then you would have arrived at the same values as the mean. I would like to point out that these are 'effective' phase angles that allow us to treat the signal as a sinusoid in these calculations. The more complex the waveform, the more difficult it is to process in this way. But looking at the actual factors involved, we see that Cos(47.69) is 0.673 and Cos(47.53) is 0.675 so the differential of 0.675 / 0.673 is .0029 away from 1 and this falls below your 2 digit rounding. So essentially excluding your phase angle in this case was the same as having a factor of 1. I think that is why it came so close to being the same thing. Something I wanted to try, and did not get a chance yet, was to compare Lawrence's index differences to actual average power differences. In other words, if Lawrence was doing the math wrong, he was doing it wrong for both the input and the output so both were inflated or deflated by the same algorithm and that may mean that the ratios held. Just a thought. Also, do you know if his scopes output any data? If he has the raw data then we could have a look at that and see what it shows. Harvey Hmmm... This might be quite plausible as an explanation if we were dealing with single frequency sine waves. How well these phase shift calculations fit in with a waveform rich in harmonics (where the phase angles will be different for each sine component of the composite waveform) is another matter, I would think. I don't have an answer to the Professor's question, but I'm not convinced that these calculations would apply quite so neatly in the case of the waveforms involved here. Humbugger « Last Edit: 2011-02-18, 15:55:37 by humbugger »

MileHigh	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #522 on: 2011-02-18, 16:03:16 »
Group: Guest	Yes sine waves rule and the output power formula only works for the phase relationship between two sine waves of the the same frequency.

Harvey	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #523 on: 2011-03-10, 11:02:47 »
Group: Guest	Interesting comments by the last three posters Since we are looking at Voltage and Current from the same source if the frequency of the two were different then we would be having discussions on an entirely different level to be sure - but certainly not beyond the realm of possibility. It would be cool to see if they could forensically extrapolate the phase angle of the periodic signals under consideration from the supplied data.

teslaalset	Re: Lawrence Tseung sent a Prototype to test... any comments? « Reply #524 on: 2011-03-10, 13:46:06 »
Group: Guest	Quote from: poynt99 on 2011-02-09, 19:21:20 Sounds good. Will do Lawrence. .99 Poynt, Just curious, did you receive the proto and did you have a chance to review already?

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