Joule Thief 101

MileHigh · April 12, 2016, 10:59:55 PM

Just a comment on Brad's post #1807.

I said, "As I alluded to before, the "phase shift" is not even real - there is no phase shift. It's just an abstraction we use to make it easier to describe sinusoidal-type waveforms you see on your scope display."

Brad thinks this is really funny and makes a long posting mocking me for several times where I mention "phase shift" in my postings.

Read again, "As I alluded to before, the "phase shift" is not even real - there is no phase shift. It's just an abstraction we use to make it easier to describe sinusoidal-type waveforms you see on your scope display."

I am clearly stating that the term is in use and I clearly have no problem with it because I use it myself. The point being that if you scope the current through the primary of a transformer and then look at the open circuit voltage on the secondary, the voltage on the secondary is instantaneous relative to the "excitation signal" of the current in the primary and happening in real time. There is no true "phase shift" if you interpret "phase shift" as meaning "shifted in time." We only describe the voltage output on the secondary as "appearing to be shifted in time" but in fact the output is an instantaneous output and not shifted in time.

That's just a subtlety that I wanted to mention because I thought it might add some value to the PW/EMJ discussion.

MileHigh

Pirate88179 · April 13, 2016, 12:03:39 AM

Quote from: Magluvin on April 12, 2016, 10:56:32 PM
Ah. I was thinking of the old modulus. Im sure everything has elasticity by some measure. But isnt it the tensile strength that determines that measure? Just of the top of my head here, not looking anything up on that. Yet.

Mags

No, tensile strength is measured by pulling. Then, there is torsional strength which is measured by twisting, and compressive strength measured by pushing together. Elasticity is the ability/property of a material to resist distortion under stress and to return to its original shape after that stress is no longer present. That stress can come in the form of the above mentioned pulling, twisting and compressing or a combination thereof.

Bill

Magluvin · April 13, 2016, 01:31:05 AM

Quote from: Pirate88179 on April 13, 2016, 12:03:39 AM
No, tensile strength is measured by pulling. Then, there is torsional strength which is measured by twisting, and compressive strength measured by pushing together. Elasticity is the ability/property of a material to resist distortion under stress and to return to its original shape after that stress is no longer present. That stress can come in the form of the above mentioned pulling, twisting and compressing or a combination thereof.

Bill

Ok. sounds right

I was thinking like this....

If we had a thin layer of carbon fiber strip, resin and cure. It would be a bit bendable as the thickness from side to side is thin. The thicker the lairs become, the stiffer the strip will be due to the outside bend would need to stretch for the bend to occur. And the carbon doesnt want to stretch due to tensile strength. So higher freq. But you are right. Carbon has very little elasticity, but still necessary for it to bend.

Hmm. just a thought. If we had a 1/8in strip of layers of carbon fiber resin cured, it will bend, but very little before it breaks. Like glass or the wine glass. So as we had seen in the vid, that wine glass had some crazy amount of distortion for glass, as we know it in normal life. So, maybe that 1/8in carbon strip would also bend a lot further when bending at say its resonant freq before breaking. If so, could we say that at resonance we can enhance elasticity? It would certainly seem so with the wine glass. Just try to physically distort it that much at any freq other than the resonant freq. I wonder if the wine glass gets warm oscillating like that?

Mags

tinman · April 13, 2016, 01:35:46 AM

Quote from: MileHigh on April 12, 2016, 10:59:55 PM
Just a comment on Brad's post #1807.

I said, "As I alluded to before, the "phase shift" is not even real - there is no phase shift. It's just an abstraction we use to make it easier to describe sinusoidal-type waveforms you see on your scope display."

Brad thinks this is really funny and makes a long posting mocking me for several times where I mention "phase shift" in my postings.

Read again, "As I alluded to before, the "phase shift" is not even real - there is no phase shift. It's just an abstraction we use to make it easier to describe sinusoidal-type waveforms you see on your scope display."

I am clearly stating that the term is in use and I clearly have no problem with it because I use it myself. The point being that if you scope the current through the primary of a transformer and then look at the open circuit voltage on the secondary, the voltage on the secondary is instantaneous relative to the "excitation signal" of the current in the primary and happening in real time. There is no true "phase shift" if you interpret "phase shift" as meaning "shifted in time." We only describe the voltage output on the secondary as "appearing to be shifted in time" but in fact the output is an instantaneous output and not shifted in time.

That's just a subtlety that I wanted to mention because I thought it might add some value to the PW/EMJ discussion.

MileHigh

Wrong again.

There is such thing as phase shift,and i gave you pacific meanings for the term phase shif-which happens to fit perfectly with transformer voltage and curret relationships.

You need some schooling MH- truly you do.
More garbage from you in order to cause incorrect understandings of simple actions.

Brad

MileHigh · April 13, 2016, 02:00:21 AM

Quote from: tinman on April 13, 2016, 01:35:46 AM
Wrong again.

There is such thing as phase shift,and i gave you pacific meanings for the term phase shif-which happens to fit perfectly with transformer voltage and curret relationships.

You need some schooling MH- truly you do.
More garbage from you in order to cause incorrect understandings of simple actions.

Brad

You are going to play the wrong again game again when you are wrong again?

Yes indeed, a signal can truly be phase shifted and truly displaced in time by things like delay lines and other stuff. In the digital domain it can be done with shift registers. In the ancient computer days it was done with a long horizontal tube half-filled with mercury. Or if the same signal travels through one meter of coax and 20 kilometers of coax, then there will be a phase shift between the two signals where they are truly displaced in time relative to one another.

But when you look at the secondary output of the transformer as compared to the primary current when the primary current is a sinusoidal waveform, then the secondary signal is not displaced in time. If the primary current waveform is a sine wave then the secondary voltage waveform will be an instantaneous cosine wave. They are not displaced in time at all, they are just different waveforms where it is convenient to say that they are "phase shifted" relative to each other.

All that I am saying is that there are two meanings for "phase shift" but like the brutal abrasive wanker you are, you have another good wank and say that I am "wrong again." Between the two postings I made about this topic I suggest that you reread both of them enough times so that it sinks in and you understand what I am saying.

MileHigh