Is joule thief circuit gets overunity?

[ltseung888]

Trying to resolve the DC Offset Problem at Zhou's Shop.
(1) A UNI-T brand DSO was used as suggested by Poynt99.  The display line was very thick and some crossing of the 0 ref line was seen.
(2) Mr. Zhou does not have the Tektronics in stock but he can order it at a relatively low price but the condition is that money has to be paid in full up front and there is no refund.
(3) Another new Atten was calibrated using the normal procedure recommended by Atten (pressing Default button and then the Auto buttorn etc.)  The crossing of the 0 reference line was still seen but the actual value appeared less.
(4) Mr. Zhou believes that a 5-6mV variance or DC offset error is within the specification or limitation of the Atten.  Using the 4-Ch tektronics may be the solution.  (There were many requests for quotes with such high end equipment in the last few days.  One Indian group asked for quotes while I was there.)
(5) Mr. Zhou suggested that I use different Atten Scopes on the same Board and check the variation.  I have three in my bedroom.  I have access to another two in Hong Kong.  Mr. Zhou has dozens in stock.  That may show clearly why the Tektronics is worth its price.
(6) Supporters' first reaction is - use the right equipment.  The cost is small compared with the potential benefits.  The "demonstrated" savings in electricity bills using the capacitor may already justify such expense.

More work but we are learning more.  God Bless.

[poynt99]

Lawrence,

I believe Instek is a fairly decent scope and I see Mr. Zhou sells those too. Could Mr. Zhou try one and see if there is an improvement?

[ltseung888]

Lawrence,

I believe Instek is a fairly decent scope and I see Mr. Zhou sells those too. Could Mr. Zhou try one and see if there is an improvement?

@poynt99.

I am sure he will try if I ask.  He is already making money on this "Lead-out energy" project.

[ltseung888]

First result from "Demonstrating longer battery life" with Demo Boards.
The results are as follows:
(1) Board 116 barebone JT with no capacitor.
      Initial Battery Voltage = 1.318V
      Battery Voltage after 24 hours = 1.252V

(2) Board 124 JT with capacitor and twin timer set to 10 seconds ON 2 minutes OFF
      Initial Battery Voltage = 1.317V
      Battery Voltage after 24 hours = 1.261V

This experiment will be continued for a few days/weeks until the LED is off?
The initial results indicate longer battery life.  Does that translate to saving in electricity bills when properly implemented?

[TinselKoala]

1. Where do those voltage numbers come from? What is the accuracy of your voltage measurement? Have you calibrated your voltage measurements against a known standard? This is absolutely necessary if you are reporting a claim that depends on a few milliVolts difference, as you are here.

2. "Apparent" brightness here is no good as a criterion for several reasons, not the least being observer bias. You absolutely need to have a reliable and accurate _instrumental_ measure of light output, especially if you are making a claim based on "similar" light outputs and voltage levels that differ by a few milliVolts.

I've already given you links for local experts with good test equipment, links for affordable and accurate voltage standards, and so on. Should I now find you a suitable method of measuring light intensity, or can you handle that search yourself?

3. We need to see the schematic for your timer in the black box. Many people have made the error of allowing power from their timer/clock/control electronics to make it through and add power to the system under test. Please show the exact schematic and hookup for your timer so that we can evaluate whether or not it might be also acting as a power supply to the circuit under test.

9 mv / 1250 mv == less than one percent.  A result that is not different from noise, being smaller than the voltage measurement error of your oscilloscope, anyway.