Joule Thief

[sm0ky2]

Well, I gave this some thought.  If you put the supercap in parallel with the led then you run the risk of over charging the cap if the energy flows into the cap faster then it is being drained by the led.  This is why I used series so the pulses get absorbed and leveled out on the way to the led and since the led is a diode we do not have to worry about any energy returning back into the cap.

I believe I did this very thing a while back and I will see if I made a video of it...if not, I will make another circuit to attempt to demonstrate what I am saying...or trying to say.

Bill

PS  This has to do with something I found out about supercaps (or possibly any caps?) in that when you hit them with spikes or pulses, they do a much better job of retaining that energy than a battery which makes them very good to use with catching spikes from a JT circuit or the pulses from my earth battery.

I made some that charged caps using a 1/2 wave rectifier off a secondary coil. Just be sure to drain the cap with some kind of load, or it could blow up!

[AlienGrey]

That looks like a straw hat led...I have some of those and they are very bright for their size.

Well done.  Will that run on 1.5 volts or lower?

Bill

Yes it will, i just tried it with an old AA duracell ! and it's about as bright too.

[Pirate88179]

MH:

Here is one of my first earth battery videos: https://www.youtube.com/watch?v=mq9ZKDKDclY
(This was before Pirate Labs)

I didn't know it at the time but I was using a .5 farad 5.5 volt supercap in series with the led.  The led would
not light without it in the circuit.  This is where I first learned how the caps can gather up the spikes and allow them to be used.  This is where I got the idea to use them later on the JT circuit.  The cap is charged by the spikes from the earth battery and later, the cap is charged by the JT spikes.

Does this make any sense now?  I knew next to nothing about electronics when I did this 9 years ago (not that I am an expert now, ha ha) but I stumbled on to something that has been helpful ever since.

Bill

[MileHigh]

Bill:

It's the corroding magnesium rod that generates the voltage and associated current.  The current is quite low and that translates into saying that as a voltage source, the corroding magnesium has a very high output impedance, too high to drive the LED reliably.  There are no spikes produced by the magnesium.  But it is reasonable to assume that the current produced by corroding magnesium is variable.  It depends on what is happening at the boundary layer between the magnesium and the soil and how much moisture and salinity there is at every point of contact, etc.  That is presumably quite variable and therefore the output impedance is also variable.

So the capacitor just absorbs the variable current and smooths it out to drive the LED.  It effectively converts the variable output impedance from the corroding magnesium rod into a more constant impedance such that the LED is driven with a more constant current.

MileHigh

[Pirate88179]

Bill:

It's the corroding magnesium rod that generates the voltage and associated current.  The current is quite low and that translates into saying that as a voltage source, the corroding magnesium has a very high output impedance, too high to drive the LED reliably.  There are no spikes produced by the magnesium.  But it is reasonable to assume that the current produced by corroding magnesium is variable.  It depends on what is happening at the boundary layer between the magnesium and the soil and how much moisture and salinity there is at every point of contact, etc.  That is presumably quite variable and therefore the output impedance is also variable.

So the capacitor just absorbs the variable current and smooths it out to drive the LED.  It effectively converts the variable output impedance from the corroding magnesium rod into a more constant impedance such that the LED is driven with a more constant current.

MileHigh

Well, we later learned some other things about this type of set-up.  For example, I hooked up my scope to the E.B. and you could see all of these high voltage spikes jumping all over the place.  They could have be coming from anywhere...leaking ac line, radio waves in the ground (noise) or possibly lightning strikes from distant storms?  Who knows...but...those spikes were there and that is why I could charge up my large cap (650 F) to 2.7 volts when I was only measuring around 1.9 volts using several different meters. (Analog and digital)

This is about the time I began calling this arrangement an earth energy receiver rather than an earth battery.  Maybe the energy was man-made...who knows?  I just know it was there otherwise, I could never have made enough power to run my Bedini motor or those Fuji circuits.

I will look for some photos of the spikes if I can find some and will edit this post later.

Here is the video showing the spikes jumping all over the screen...they are hard to see but they are all over the place.

https://www.youtube.com/watch?v=qjBAU4HAMfs


Bill