Is joule thief circuit gets overunity?

[picowatt]

I did the DSO analysis on Board 80 again with the latest "correct" setting.

The negative Input Power is now taken to be Current drawn from the battery.  Thus the COP is now positive.

The COP is still 1.41.  The Average Output Power is still greater than then Average Input Power.

More research is worthwhile.

Lawrence,

Do you have a completed spreadsheet of slide 12 (board 80 input)?

PW

[picowatt]

Lawrence,

In your recent post #549 of board 80's input power, the waveshapes and frequencies are different from that which you posted in your reply 503.

Slide 12 of post 503, which is supposed to be the input power capture for board 80, is at 3KHz, the same as the output power slide .  Both of the recent posts of board 80's input capture have different frequencies and wveshapes.  The only input power that can compared to a board's output power is one that was performed as close to simultaneously as possible.

Also, when comparing the input and output data, you should attempt to sync up the data as best you can.  As TK has suggested, try looking at both the inpuc current with CH1 and the output current with CH2 on the same scope.  You will then be able to recognize the true beginning of a cycle when you use two scopes.  You can then collect a bit more data length than you need and edit your sample list from each scope so that you are sure they both contain the same number of cycles (i.e., have the same beginning and end point relative to an integral number of samples).

Alternately, you might try using a fifth probe connected to the output voltage point (top of LED) and connect that probe to the external trigger of the first scope.  The output voltage waveform has a fairly fast risetime so by triggering both scopes from that point, you will be more assured of having the same number of full cycles in your sample data.

To sync up even closer, you could use 6 probes total, with the tips of probes 5 and 6 cboth onnected to the output voltage point and each used to drive the externa trigger inputs of the two scopes.  Using 10X probes shouldn't overly load that point and by setting the triggers on both scopes to external, rising edge, and the same voltage, you will be assured of at least some degree of reasonable sync triggering.  All input/output capture images posted will then be time aligned between the two scopes to a fair degree.

PW     

[ltseung888]

Lawrence,

Do you have a completed spreadsheet of slide 12 (board 80 input)?

PW

See Reply 552.  That completed spreadsheet is for Board 80.  It has the Average Input and Output Power, the COP and the graphs.  Please study and comment on it carefully.  It will be presented to the Hong Kong Government.

[ltseung888]

The oscilloscope analysis for Board 107.


Average Output Power
12.05105778 watt
Average Input Power
0.009865636 watt

COP = 1221.52

This Board 107 will be carefully studied and preserved.
 

[ltseung888]

Lawrence,

In your recent post #549 of board 80's input power, the waveshapes and frequencies are different from that which you posted in your reply 503.

Slide 12 of post 503, which is supposed to be the input power capture for board 80, is at 3KHz, the same as the output power slide .  Both of the recent posts of board 80's input capture have different frequencies and wveshapes.  The only input power that can compared to a board's output power is one that was performed as close to simultaneously as possible.

Also, when comparing the input and output data, you should attempt to sync up the data as best you can.  As TK has suggested, try looking at both the inpuc current with CH1 and the output current with CH2 on the same scope.  You will then be able to recognize the true beginning of a cycle when you use two scopes.  You can then collect a bit more data length than you need and edit your sample list from each scope so that you are sure they both contain the same number of cycles (i.e., have the same beginning and end point relative to an integral number of samples).

Alternately, you might try using a fifth probe connected to the output voltage point (top of LED) and connect that probe to the external trigger of the first scope.  The output voltage waveform has a fairly fast risetime so by triggering both scopes from that point, you will be more assured of having the same number of full cycles in your sample data.

To sync up even closer, you could use 6 probes total, with the tips of probes 5 and 6 cboth onnected to the output voltage point and each used to drive the externa trigger inputs of the two scopes.  Using 10X probes shouldn't overly load that point and by setting the triggers on both scopes to external, rising edge, and the same voltage, you will be assured of at least some degree of reasonable sync triggering.  All input/output capture images posted will then be time aligned between the two scopes to a fair degree.

PW   

@PW

Poynt99 has a 4-CH DSO.  All the top Universities in Hong Kong (and the World) are expected to have top of the line 4-Ch DSOs.  I sow seeds only.