Is joule thief circuit gets overunity?

[TinselKoala]

On reply 771, both scopes showed CH1 Vrms = 500mV because I adjusted the DC Power Supply so that such values are shown. 

I see. Thank you for the explanation. But do you have any independent confirmation that you were actually supplying 500.0 mV from the power supply?
I have found that the meters on power supplies are generally not all that accurate and should be supplemented by DMMs right at the input to the device under testing.
But since you are no longer relying on your Attens, the question is moot, I suppose. Still, it's curious that the DC signal from the power supply gave readings that agree, but the JT readings disagree so much.

You should rent a scope from Mr. Bahng's company before you buy one. Why throw good money after bad, even in China? You may find that the rental gives you all the data you need, and you won't have money tied up in an expensive scope that sits on the shelf and gets very little use after this.

[ltseung888]

I see. Thank you for the explanation. But do you have any independent confirmation that you were actually supplying 500.0 mV from the power supply?
I have found that the meters on power supplies are generally not all that accurate and should be supplemented by DMMs right at the input to the device under testing.
But since you are no longer relying on your Attens, the question is moot, I suppose. Still, it's curious that the DC signal from the power supply gave readings that agree, but the JT readings disagree so much.

You should rent a scope from Mr. Bahng's company before you buy one. Why throw good money after bad, even in China? You may find that the rental gives you all the data you need, and you won't have money tied up in an expensive scope that sits on the shelf and gets very little use after this.

Mr. Bahng's company has the same terms as Mr. Zhou but much more expensive.  There is NO renting for the Tektronics but he can order it for me.  I do not worry about money - since it does not come out from my pocket.

[Pirate88179]

The various JT threads on this forum document much more efficient JT circuits than this one here. The circuit under test here is the "JTBasic" circuit using a toroid and a 2n2222 transistor. Other transistors in this same circuit work "better" in the sense of being more efficient still, and slight modifications to the circuit, such as placing a 70 nF capacitor in parallel with the base resistor, make it even more efficient. If you get into optimizing the transformer, you can reach incredibly low levels of current input while still making appreciable light in a low voltage LED JT, and I've shown several times my HVJT which lights up six 90-volt NE-2 neons in series, from a single AAA battery, or even wirelessly without an onboard battery at all.

You can look thru the forum for Pirate's and Groundloop's and LaserSaber's and some other circuits for JTs that are amazingly efficient and powerful. There are many variations depending on what you want to test. My personal favorite is still my HVJT. It's not especially efficient, I optimized for high voltage, but it's cute, you have to admit that much.

TK is correct.  Gadgetmall has a JT circuit that will light an led off an AA battery for over a year.  So does Lasersaber.  Nothing against Lawrence's efforts here but his JT's are at least 2-3 years behind the work shown in the main JT topic area.  Oh, and those are not claimed to be O.U.

Nice circuit TK.

Bill

[ltseung888]

Continuing the experiment into Day 3.  It is only 5 am now.  I should take the reading at 9am.  But I plan to be out this morning and shall not be back until the afternoon.  Thus I post the result now.

Note that the voltage on Board 116 showed a big drop with the LED still ON.
The Voltage on Board 124 with capacitor and timer is still quite high.
Adding the capacitor and timer appears to make a big difference.
@testers, please try this test.  If you need more boards or capacitors, email me.

It is 3 pm in the afternoon now.  I came home.  Both the LEDs are ON but now Board 124 (with the capacitor and timer) LED is much brighter.  I know that we are still in the middle of the experiment.  What can we do with such results?  What should the next set of experiments be?

I sow seeds.  Are these rotten seeds???

[TinselKoala]

1. You have no instrumental measurement of light output. Your subjective evaluations of "brightness" do not equal an output power measurement.

2. You have no assurance that the batteries had the same amount of energy in them to begin with. Voltage is not energy; the starting energy content is not known. You should repeat this experiment with capacitors as the power sources.

3. Just as your oscilloscopes have been shown to be inaccurate, it is possible that your DMMS are as well. You need a voltage standard for comparison. I have shown you how to obtain a reasonably cheap (65 dollars US, iirc) standard of high accuracy delivering 5 voltages of your choice. Do you understand the process of instrument calibration? One plots the instrument reading (the dependent variable, vertical axis) against the actual supplied voltage from the standard (the independent variable, horizontal axis). Five points allow you to interpolate a line, and then when you read your instrument you can look up the corresponding _actual_ voltage on the graph.

4. You have not given any assurance that your timer is not supplying power to the circuit under test. I have asked you for a schematic and other technical details of the timer so that this matter can be evaluated. A _tiny_ amount of power leakage from the timer could be more than enough to fool you into thinking you have some advantage. This issue must be addressed, not ignored.

5. Finally (for now) if your timer is necessary to achieve the effect.... then you must include the power _supplied TO_ the timer as part of your total input power to the system, whether or not any of this leaks through to power the LED.


Since no seeds that you have sown have borne sweet fruit, it is important to find out why, don't you think? We already have identified major problems with the Atten scopes that would seem to poison all fruit harvested with their aid. The Divine Wine is going off, turning to vinegar, and your seeds are wasting the Gardener's time and effort. You need to concentrate on pulling up the weeds before you can tell if your fruit is going to be sweet or sour.

Directly across the street from where I live there is a large orange tree. Every year this tree is heavily laden with beautiful large oranges; they fall to the ground and the children use them as balls, or throw them at each other in mock combat. Nobody can eat these large, beautiful oranges, because they are as sour as lemons and as juicy as a dry sponge.  Fruit is not always what it appears to be, as the taster often finds out to his chagrin.