Joule Thief: A Measurement Pitfall

Naive measurements of power in high-frequency circuits can produce faulty readings even on good equipment.

The Joule Thief is a simple circuit with subtly complex behaviour that is easy to miss or ignore.

Or, worse yet, to misinterpret.

Category:

Science & Technology

Tags:

• measurement
• oscilloscope
• joule
• thief
• inductance
• current
• monitoring
• ufo
• free
• energy
• buddha
• overunity
• cheese
• danish

[overunitydotcom]

Please have a look now at the Joule Ringer circuit.

As you have this great measurement equipment you should take a look

at this mysterious circuit that keeps on running and running....

Many thanks.

Regards, Stefan.

[TinselKoala]

@overunitydotcom

What's mysterious about it? It uses principles that I have been emphasizing for a long long time: get away from ferrite cores, use air core coils that are 1/4 wavelength resonators, go for the shortest possible rise time in the primary pulse, so that you get the highest possible voltage produced in the secondary with the least voltage input to the primary.

I am glad to see these principles -- that is, real Tesla technology -- being put into use in the Joule Ringer.

[conradelektro]

Let's consider a correct measurement of the voltage drop over the 1 Ohm shunt:

it shows an interesting feature; the voltage rises from 0 steeply to a positive value, than drops gradually to a negative value, and finally steeply back to 0. Does this mean some power is fed back into the battery when the voltage drop is below 0?

It puzzles me whenever I measure the power consumption of Joule Thief over a shunt, Conrad

[TinselKoala]

@conradelektro

No, what it indicates is the very same energy "sloshing around" between the inductances and capacitances represented by the wires and the space between. A classic signature of an inductive "ringdown".

Since the energy is the same energy sloshing around, and dissipating, and the ring waveform goes negative, positive, and so on.... there is really no or nearly no effect on the energy integral. The integral reads the same, with the reference in either location.

[TinselKoala]

@TinselKoala

(continued) But readings taken with simple meters will respond to the spikes and give different input values to a manual power and energy calculation, depending on where the reference lead is placed.

[shubus]

I, for one, am glad to see this clear and plainly stated explanation of how some of these measurement fiascos are occurring on the forums we've been seeing for these many years. Of course we all know the cheap Chinese meters is usually the main culprit, but here is another one. Just wish it didn't take a $13,000 scope to show it. Thanks for help clearing the air, TK.

[nonesounique]

Haha. Looks a lot like what Lawrence Tseung showed on his scope shots. Maybe the delusions are real!

[rave154]

great & clear Demo there Tinsel,

alas, i fear that this will make no difference what so ever to Tseung as he worships at the Church of Peak-to-Peak Values......or is it the church of Santa Claus.......ive forgotten now.....wait, i remember, its Mickey Mouse !!!!

[overunitydotcom]

Well done TK,

yes, with high frequency every cm of wire counts as an inductance,

so it is really advised not to use croco-cables as these add too much inductances.

So better solder all your circuits with short leads and use stranded cables for better RF conduction.

Regards, Stefan.

[Pirate88179]

But TK, you were not using an OU JT in your video. What is Lawrence going to do now? Please note, I have never claimed OU for any JT, although the Jeanna circuit is so efficient that I don't really care as it can run stuff for a long time.

Yet another great, educational video...thanks.

Bill