Joule Thief

[jeanna]

Hi everyone,
Well, I have never read a manual through even once. This time I read it through 2 1/2 times before I turned on my new hand held oscilloscope.

I cannot tell much yet. It certainly does work. If I put it on my fingers or temple or brain stem area I get different waveforms.

So, I sat down to gingerly test a jt. I was holding the secondary in my left hand and my right hand was holding  the probe probably right at the tip and I saw a jt type of waveform. It was the skin effect being read by the machine. That is cool.

Then I put the probe directly onto and read the secondary and got a waveform

THEN, I changed body positions and saw the waveform again  and realized I was holding the probe just over the center of the core of the toroid. It was not touching anything just hovering over the center of the core.

I then put the probe on the opposite side and the wave was still very spiky but different and it went in the opposite direction!

I need to read the manual a couple more times, I think, to find out how to freeze the frame it so I can study what I am seeing. Man, this is cool.

Altrez, this is $189 from allelectronics. It is made by Velleman. The one they sell at allelectronics is the slightly less fancy one, so you could find the one with the back light and the ability to send the info/screen to your pc. but this takes 5 AA'a and I think it is gonna do what I need. (as long as I can find my magnifying glass!)  check it out.
@Altrez,
When you have the dmm probes on your secondary testing for continuity, don't you see a voltage too?

jeanna

[altrez]

@jeanna

I read no voltage on the pickup coil. Thanks for the advice on the O-Scope I will check them out

Thank you so much!

[jadaro2600]

@gadgetmall,

Interesting piece of work you've got there! What the heck is it?

@jeanna,

It's good to have one of those, I wish I could afford one that works with linux - my issue is with the frequency range of the devices.

I noticed that the toroids are sensitive - they whole oscillator is sensitive to temperature, etc.  You should take readings at initial startup and after every minute for five minutes - it may give you a better overall result - I'm not sure what kind of documentation you do of your own work; this is just the scientific advice.

[Pirate88179]

@ Gadgetmall:

Very interesting post.  The main thing that jumped out at me is the term "Metglass".  We, (My father's ceramic company) made the original nozzles for this process developed by Allied Chemical in Parisipanny, NJ.  We made them hundreds of these nozzles and the process involved pouring molten metal onto a 15 foot diameter water cooled wheel.  The metal instantly crystallized and formed an heretofore unknown metal with very unique electrical properties.  This is the single reason that starters for vehicles, as well as alternators got about half the size and still put out the same, or more.

We used ultrasonic impact grinders to generate the very accurate slots required for these nozzles which were made from zirconia.  We also had to machine some very accurate details using diamond surface grinders as well to allow them to mate with the machine.  I used to have some strips of this stuff but, where it went, I have no idea.

Anyway, this brought back memories for me...thanks.  Now I will go back and see if I understand anything else about it.

Bill

[jeanna]

@jeanna

I read no voltage on the pickup coil. Thanks for the advice on the O-Scope I will check them out

Thank you so much!

I just had a thought.

Are you wrapping your secondary wires through the center of the loop? (like where your girlfriend is standing when she is dancing with the hulahoop.) I know the solution is simple. I got a led to light with just one loop through the center. It was brighter with 2 loops, so I recommend starting with 5 loops, but no more.

One other possibility... MK1 found there is a dead spot just opposite the place where the wires connect. I don't think it is dead enough for you to get nothing, but maybe...

jeanna