Joule Thief

[xee2]

@ Pirate88179

What in that circuit makes the led blink exactly? 

The time it takes the capacitor to charge up.

[Pirate88179]

Xee2:

Ah, thank you.  I see now.

Bill

[jeanna]

Wonderful xee2,

I hope that was the train and not the led making the roaring sound? 

I like to know the limits of things, and finding the lower limits seems safe for early tests. I often learn a great deal by having this outlook.

So, is this circuit which is feeding back into its own battery using more energy from the battery? or maybe it is using less. I bet you already told me in the corner with an amps draw number.
How would this work with a supercap instead of a battery, I wonder?

I have been making myself dizzy today trying to wrap my head around matching inductors to capacitors.

When you are doing this, do you have a rule of thumb that you use to get close to the right match?
Here is the problem:

The earth currents seem to oscillate at a rate of about 2.25 to 2.50Mhz and I want to create a tank circuit that will resonate along with them, .......?

I went to Barrys coilgun site. There I came to the conclusion that I could wrap a piece of 24g or 26g wire around a straw  7T and with a 10kpF cap in series it would oscillate at that rate. Later at deep fried Neon, the number was confirmed for a parallel cap.

Is this the way you would go about it?
To first calculate the resonance amounts of cap and inductor to match the frequency?

Sometimes I feel close and sometimes it all eludes me.

I will try that straw inductor I just mentioned. The cap is surprisingly high value. I would figure a much smaller amount for such a high frequency, but I am just learning...

thanks for the circuit too,

jeanna

edit.
While I was typing you were explaining this to Bill. I like this.
166 days eh?

Bill, you could make a drum machine out of something like this!.

I really like it. The tank is what is doing it. very nice.
j

[xee2]

@ jeanna

This was experiment at reducing power to see how long JT could run on super cap. I do not have a super cap, but I am sure it will not run anywhere near as long as on a battery. A lot of the power goes back into battery. A battery cap may help catch the returned power. I do not know more. It was just a test. Can you re-post link to cheap super caps? I looked but could not find them.

[Pirate88179]

Xee2:

Here you go:

http://parts.digikey.com/1/parts/90420-capacitor-ultra-10f-2-7v-radial-eshsr-0010c0-002r7.html

These are $3.54 for 10 Farads.  This is a pretty good price for this size.

Bill