Joule Thief 101

[tinman]

Todays schools going to common core is similar to some peoples 'teachings' here.

I had seen a vid the other day about how we used to learn things in school, back in the days. The guys said that today they try to make the students figure things out without first teaching them how to do it. And if you look at some of the ridiculous test questions, you can see there really is no way to provide an answer. Some of the questions are particularly loaded to not being able to figure them out.

But back in the day, teachers would work with us and teach us things each week. If we comprehend the teachings, then on test day we are able to answer the questions in tests.

here are some examples...... 

Mags

And all to often we have teachers that cannot answer the questions they ask the students.
Is MH one of these teachers?--well,we shall see soon enough.
If the question is basic !001! electronics as he claims,then a full and accurate description based around his given perameters should be a piece of cake.


Brad

[MileHigh]

I am just posting this to make it clear that I am no liar as has been alleged many times.

Me:  It's just like you saying something about your coil being sealed in epoxy therefore you couldn't see the direction of the windings therefore you couldn't add the dot convention to your schematic.  Thus we are led to conclude that you are incapable of inventing a way to do your own test?  Another jaw-dropping moment.

Brad:  Another lie,as i clearly stated as to how i could define the dot convention with that post.
Please stop your lies MH.

Brad, you said this on April 18th:

<<< CH1 is across the secondary /5 ohm resistor,and CH2 is across the 3 ohm CVR.
I do not know the dot convention,as the primary is sealed in apoxy resin,and i can find my compass.  >>>

<<< I will be winding a new 1:1 coil tonight,as requested by Poynt,and will be able to supply the dot convention.
I cannot determine the winding direction of the primary winding of the transformer,as it is taped and lacquered,and the wire very fine. Guess i could use a compass and DC current to work it out.  >>>

I did not see any clear statement for how you could "define" the dot convention.

I am no liar, but based on what you are stating above I am forced to conclude that you are unable to come up with a ridiculously simple test to determine the dot convention for a transformer.  Assuming that I am correct, that's a real shame.

Yes, you do indeed mention a compass, and I suppose that if push comes to shove you could use a compass to determine the dot convention for a transformer that puts magnetic flux in the open air, although it will not work for a closed-flux-loop transformer.  Considering that there is a pretty obvious and self-evident way to determine the dot convention that is so easy and so quick that will work for any type of transformer with standard bench equipment, your compass remark did not stick with me.  What I really remembered was the shock in reading you say, "I do not know the dot convention,as the primary is sealed in apoxy (sic) resin."

I only made this posting to make it clear that I am no liar.  I suppose that technically Brad is correct, and you really can use a compass to determine the dot convention for an air-core-type transformer if you really want to go that strange route.  Or Brad will have a miraculous alternative explanation that clears up the misunderstanding.

MileHigh

[poynt99]

At t=0, I think the universe might blow up 

[Magluvin]

I was thinking,,,

If when you dump the charge in cap you end up loosing 1\2 the energy that was used to charge the cap,, where does it go.

MarkE stated that there is a trade off between how much you dump and what the costs are,, as in,, if the change in voltage is smaller then there is more of the stored energy transferred per cost to replace.

Here is the thing,, I can do this mechanically with almost no losses so why not electrically?

So,, I need to make sure that what I thought was how to look at the energy value was close enough to start with,, setting a base line if you will.

So my 30V @540uf if used up should show about 5.9V @ 14000uf on one cap,, and many variations when going into 2 caps,,

Right now I am loosing almost all of it into the spark and bang   but you have to start from somewhere.

Ive thought of that many times. Even argued it a few times.


If we had 2 air tanks, 1 full at say 100psi and 1 empty.
Then we dump the full into the empty till they are equal. What did we lose?  We lost pressure.

Say each tank is 1cu ft. The one thats full is able to accomplish a certain amount of work over time, depending how you release it. But if we dump that full tank into the other till both are equal, we now have the total amount of air in 2 cu ft. 50psi each? Now if we calculated the total amount of work that can be done with the total of what is in the 2 tanks, we will find that we could do more work with the full one cu ft tank than we can with 2 1cu ft tanks described above after the dump and equalization.

Now we could introduce an air motor, motor driven with air that can also pump, and we put a flywheel on the motor shaft, that would enable us to release the full tank into the empty tank through the air motor/flywheel and be able to transfer most of that air in the first tank into the empty tank. Like having a full cap and dumping it into another empty cap through an inductor and a diode and get most of the full caps energy into the empty cap, minus minimal losses.

They say that if we dump a cap into an empty cap that the reason for the 50% loss is due to resistance in the transfer. I still fail to believe that. I believe we have just wasted the full caps energy by dividing its voltage/pressure into a cap/container that is twice as large. Where we lost it is in reduced voltage/pressure, not in resistance losses. We lost it in a stupid way. We didnt do anything with the energy transfer.   

Example.....

We have one full tank and one empty. We dump the full tank into the empty tank and the pressures equalize.

Now, we have our full tank and dump it into the empty tank, but we use the air motor to make the transfer. Now we can do work with the air motor until the 2 tanks are equalized.  And we still have the same amount of pressure in each tank as when we did it the stupid way.

Im still trying to figure out the 'reasoning for blaming' the loss on resistance/heat when dumping a full cap into and empty one of the same value.    There is something wrong there.

That would be an interesting debate thread.

Mags

[MileHigh]

At t=0, I think the universe might blow up 

Trump might indeed have the "football" so let's hope being the most powerful man on Earth chills him out a bit.