OverUnity prize money 15825 US$ total until now

[poynt99]

Stefan,

How will you measure this GJT to ensure at least 1W of power is being supplied by its output?

I would not rely on the specification of an LED. LED's can run on a wide range of voltage and current inputs, above its minimum. You can run a LED off 20mW or so (i.e. 10mA @ 2V).

I would suggest dispensing with LED's as an output power indication in favor of a 0.5W or 1W suitable value* carbon resistor. Do a control test with a DC supply and see what temperature the resistor is at with 1W input power. Then monitor the resistor's temperature for the DUT test to ensure it remains at that temperature, or higher. *A value that results in a temperature rise of say 20 to 40ºC above ambient.

As a side note, the applicant would be wise to tweak the submitted device to put out the amount of power he thinks will make the device last the 3 months and still maintain the minimum 1W output.

An AA battery should be able to source 1W of power for about 3.75 hours (assumed 1.5V output). This control test being with a standard Ohmic load, for example a 1.5 Ohm resistor. At this point, the battery would have fallen to a certain percentage of its full charge voltage. The battery however is not fully depleted of its energy.

It should be noted that using this same battery in a step-up circuit such as the JT, the time duration of this 1W output power can be extended quite a lot for two reasons:

1) The average load current on the battery is lower than with the control test, and

2) The JT facilitates access to more of the battery's stored energy, depleting it far beyond what the control test will while still being able to maintain the 1W power output.

I estimate therefore, that the AA battery would be able to charge the 650F cap from 0V to 2.6V about 8 to 10 times using the JT to charge it.

So I would suggest the temperature monitored resistor as the output power indicator (use a thermistor attached to the resistor), and see how long the GJT can keep the heat on. This will require some tweaking of the switching circuit which dumps some of the cap's energy back into the battery, such that it does so before the resistor's temperature drops below the required minimum.

For a 1W constant load, I will be surprised if this circuit (powered by a 2500mA AA battery) lasts more than 10 hours, which is a little shy of 3 months.

.99

[MileHigh]

Hey Poynt,

Assuming that whatever variation of a JT circuit tested makes exclusive use of an inductive collapse going through a diode as the power output of the device, then there is an alternative way to monitor the power output of the DUT.

If you replace the ultracapacitor or whatever the load is in the "charging battery" (or blinking LED) position with a resistor in parallel with a large capacitor, then you can simply monitor the capacitor voltage and derive the power dissipation across the known resistor.

In this case the value of the resistor is somewhat arbitrary, but you might want to use a value that results in a capacitor voltage of perhaps between two and five volts.

It is very simple, just take spot measurements of the capacitor voltage at your chosen interval, and that's it.

A simple spreadsheet could be used to do the energy integration as an option also.

No heat issues - change the low-pass filter from a thermal one based on the thermal capacitance of the load resistor to an electrical one - a big cap in parallel with a "drain" resistor.  Use a multimeter!   

MileHigh

[poynt99]

MH,

That's probably a viable method as well.

However, I just try not to change the circuit too much in order to keep the folks happy. I think the thermal method would work quite well, with minimal disruption to the operation of the circuit.

In this case they like their ultra-caps, so I left that part untouched.

.99

[PaulLowrance]

I understand the skepticism but what i don't understand is why no one builds one and proves me wrong along with all the negitive comments i am getting ? flamed left and right by justa few .It is as easy as making a pie so why not make a pie ? there are no varables / nothing "tricky" .
Albert

I already told you that I will, and told you that I bought the 650F bcap. The seller can't teleport the bcap to me, so be patient.

We're all looking forward to seeing your video.


Stefan, we all look forward to you & others verify the real machine in person!

Paul

[PaulLowrance]

[Never mind. I was just thinking out loud.]