Is joule thief circuit gets overunity?

[ltseung888]

@Lawrence. Here's an overview on using a differential oscilloscope probe when making low power measurements with a scope. The author of the article also recommends a current probe for low power current measurements as well.
http://www.edn.com/electronics-blogs/scope-guru-on-signal-integrity/4403528/Low-power-measurement-techniques

However, any testing I am going to do will just be with regular single-ended scope probes, so I will have to work within those limitations with the understanding that the margin of error will be higher. I do have a current probe for my scope, but it is cheaper quality one and it has poor shielding and is very susceptible to EM fields. I don't find it is any much more accurate than my regular scope probes.

Do not worry about the low current/power input for now.  We can always use the 2n3055 and much higher Input Voltage such as 12V Car batteries.  The load can easily be 1,000 LEDs.  The present experiment is to iron out the bugs and do simple proof of concept.

[ltseung888]

It looks like the use of rechargeable batteries for Board 116 or similar makes a difference in battery life (or LED lighting time).

After the batterry hits the 0.4V mark, the LED with rechargeable battery continued for at least 3 days.  The LED with normal batteries died within 12 hours.  I now have 8 rechargeable AA batteries to try.

[ltseung888]

Board 119 results posted here first.  The Board will be sent to void for verification after all tests are done.  The process will guarantee to have at least one independent verification.

[TinselKoala]

1. Your trigger is set out of the range of your signal on CH1. This means that your scope will not be triggering accurately on some known and consistent portion of the signal waveform. This may be the root cause of the frequency error, or that error may be independent of trigger setting.
2. Your scope is reporting values that do not correspond to the trace indications, as I have noted in the diagram below. The discrepancy is most marked in the frequency error.
3. The "average" value of "zero" for the current trace is clearly incorrect, does not agree with the trace position, and most importantly IS SMALLER THAN THE KNOWN VOLTAGE ERRORS of your oscilloscope. This entire trace does not represent data at all; it is impossible to know, with your equipment as shown, whether it is noise, or represents a + 3 mV or a -3 mV true average. It looks to me like the trace is indicating about -2 mV average, but as I said, this is an unreliable measurement, beneath the noise and accuracy floors of the instrument, and thus meaningless.

Lawrence, the combination of your low level of scoposcopy skills and your inaccurate Atten scopes results in a lot of wasted time and effort, for yourself and everyone else interested in your work. Please put those miserable Atten oscilloscopes on a high shelf and refrain from using them in attempts to claim "overunity" or high COP results. Also, you might like to do a little bit of homework on the use and abuse of oscilloscopes. There are many good references, university lab class lecture notes, YouTube tutorials, and other sources of information on the use of scopes to make measurements, and how to avoid the pitfalls that have already entrapped you many times over.

[Void]

1. Your trigger is set out of the range of your signal on CH1. This means that your scope will not be triggering accurately on some known and consistent portion of the signal waveform. This may be the root cause of the frequency error, or that error may be independent of trigger setting.
2. Your scope is reporting values that do not correspond to the trace indications, as I have noted in the diagram below. The discrepancy is most marked in the frequency error.

I find the frequency determination routines in these type of scopes is not very reliable over all. In the scope shots I posted previously for my second test the frequency readings were all over the place. When I want to get a frequency reading from my scope I usually just determine the waveform period myself from the scope trace and then determine the frequency that way. I have found that the frequency reading calculations my scope does are usually not very reliable unless you have fairly simple and clean waveforms. As far as Lawrence's other readings being off, that may be because of the trigger setting being off and/or because the signal is quite a bit in the noise level, and this may be throwing off the scope's auto measurements.

@Lawrence, if there is a way that you can run these same tests at higher input voltages so that your signal to noise ratio is higher, then your measurements should be a lot less prone to error.

@Tinselkoala, it seems my scope does not have a waveform integration feature. The user manual is pretty poor however, but it seems my scope does not have that feature. It may be only higher end scopes that have that feature? I think the best method for trying to determine power with the type of DSO I have would be to log the voltage and current data points to a file and then do the instantaneous power calculations in Excel like Lawrence is doing now.

@Tinselkoala, @Lawrence:
Is the method used to determine the average power from the data points, to calculate the instantaneous power for each voltage/current data point set, and then take the average of all the calculated instantaneous data points by summing all the calculated instantaneous power values and dividing by the number of data points? Or is there more to it than that?
Is this method considered to be a fairly accurate way (within the accuracy limitation of the scope) to determine average power?

- void -