Joule Thief

[TheNOP]

The question on the whereabouts to place your probes, I you are referring to circuir "orphanwithlights.jpg" which I think you are.

Looking at the right hand part of the diagram, one would place the clip to the earth being the neg battery side, probe could be placed anywhere else.
That said, we now tackle the substance of your question, relating to 2nd Tier.


OK, now for placing probes on the 2nd Tier side.
This side of the circuit is "floating" in regards to the 1st tier, as there is no actual physical electrical wire connection to it.
Any measurements will not be accurate, if you leave your earth cro clip, on the 1st tier.
.
So you need to establish a new "terminal point" to make your measurements, try cliping the probes earth lead to the (-) as seen which feeds the 2nd Tier circuit. make all your measurements from this "point".

Looking again at you new circuit you have two DC outputs being made from your 2nd Teir, The 1st output, is derived from the 2nd Torid itself, driving the single LED, the 2nd output, is derived from the 2nd secondary which is driving the 2 LEDs as seen.

So if you clip the probe earth end to the Negative, from your 1st Torid secondary output, as the base point to take readings, you should have success.

the accuracy of the measurements will be as accurate as the accuracy of your equipment, no matter where you put the probe.
it could be meanningless measurements in some cases, but that have nothing to do with the accuracy.

it all depends on what you are trying to find.
you can try to put a led(s) from the - side of the battery and the second jt pickup coils if you want.
you are only limited by your imagination.

one thing jeanna could measure is the voltage difference between where she put one set of  led(s) and the other set.
trying to find witch place is best and if placing a bypass wire help either set.
if yes, what are the trade off.

because trade off there will be.
it is nature's ways, there are always trade off.
the question is: are those trade off are in your favor...

[jeanna]

So you need to establish a new "terminal point" to make your measurements, try cliping the probes earth lead to the (-) as seen which feeds the 2nd Tier circuit. make all your measurements from this "point".

Looking again at you new circuit you have two DC outputs being made from your 2nd Teir, The 1st output, is derived from the 2nd Torid itself, driving the single LED, the 2nd output, is derived from the 2nd secondary which is driving the 2 LEDs as seen.

So if you clip the probe earth end to the Negative, from your 1st Torid secondary output, as the base point to take readings, you should have success.

Excellent Jim,

I have been wanting to measure this and measure it with out the lights. Many times the lights take a great deal of what looked like power from the secondary. One light might take the power down by 10 or more volts.

I put the clip on the neg incoming from the first tier secondary and then turned on the scope.

I assume this is how it sets up that baseline for all subsequent tests. Please correct me if that is wrong.

Then I looked at a bunch of places. They were all between 4.62v and 6,93v.

But most interesting to me was between the bjt led and the baseline with and without lights.
So, with all 8 lights the voltage here was 4.62v.

With all lights removed except one in each parallel row, the reading was 6.42v

I can remove the last light from the secondary of this second tier, and the voltage like this is 6.93v but the led must stay in the bjt led place.
If I short that line with a jumper or a 4001 diode the voltage goes out.

Thank you. This helps me complete the tests on this one.

jeanna

edit.

one thing jeanna could measure is the voltage difference between where she put one set of  led(s) and the other set.
trying to find witch place is best and if placing a bypass wire help either set.

I need to check those places in the morning. I did get 8.73 between the 2sides of the secondary leads with the lights removed

And the bypass wire is what the orphaned wire that used to go to the base of the transistor does. the magic, if you will.
Thanks too theNOP

[Pirate88179]

@ All:

I noticed earlier today that Stefan has moved this topic, and the diagrams topic to our own Joule Thief Heading in the forum.  I just wanted to comment that I think this is a good thing and I appreciate Stefan doing this for us.  Thanks again for everyone's hard work and inspirational posts.  Also, thank you Stefan.

Bill

[electricme]

@ALL


I have an idea, which I passed by Bill, as he is moderator, he thinks it is cool, but asked me to pass it by everyone here first to get everyones opinion first.

Those who have been following this thread have lamented at times (me also) the lack of an Index about all the major posts.

So I am willing to pop my hand up and make a index, which could be placed at a significant area on the forum, say at the 500th post.

To do this, I would have to "reserve all the pages" in Post 500, buy presenting some blank posts with the words RESERVED for FORUM INDEX   

The posts would continue onward from 501.

If everyone is all in one mind and thinks this is OK. Please let us know. 

We are in the 490's now so P500 willl have to be reserved very soon.

Bill as moderator said to me, he will remove the RESERVED pages to insert the INDEX when it is ready.

jim
     

[TheNOP]

@electricme and Pirate88179
if for whatever reasons the number of posts per page change, it will have to be changed back again.

instead
what if a new tread, like the schematic one, was done in place ?
with only links in it ?
with short descriptions ?
what is important and what is not ?

it kinda duplicate the schematic/photo tread tho.
if you look at it, each posts has the cross reference link to the initial tread post.