Joule Thief

[TheNOP]

That's right and the 240 stuff will also last longer!  Well not sure if the last sentence is correct!

i am not sure if it is true either.
but i assume, since both filaments are made differently in size, one should last as long as the other.

[jeanna]

Hi everyone,
I have been reading one of the Tesla lectures today.

He says that it is not so much the frequency itself (in a certain application) but the rate of change of the frequency that makes the big difference - or big something.

My question is what would be the rate of the change of frequency over time? (that is what he said)

The frequency is the number of pulses over time so pulses per second- Hz
The rate of the change of the frequency over time. Hz²?

It reminds me of acceleration per second per second.

I see waves of pulses moving over time on the scope. If all the pulses were the same height and distance apart in time maybe this would be weaker than the pulses as I see them. But what I see does not seem to me to be change of frequency over time it is more change of strength or height of pulse over time. The tops of the pulses changes over time and gets higher and lower sometimes in a beautiful and complex pattern.

Still not sure what he meant.
Does anybody know?

jeanna

[TheNOP]

Hi everyone,
I have been reading one of the Tesla lectures today.

He says that it is not so much the frequency itself (in a certain application) but the rate of change of the frequency that makes the big difference - or big something.

My question is what would be the rate of the change of frequency over time? (that is what he said)

The frequency is the number of pulses over time so pulses per second- Hz
The rate of the change of the frequency over time. Hz²?

It reminds me of acceleration per second per second.

I see waves of pulses moving over time on the scope. If all the pulses were the same height and distance apart in time maybe this would be weaker than the pulses as I see them. But what I see does not seem to me to be change of frequency over time it is more change of strength or height of pulse over time. The tops of the pulses changes over time and gets higher and lower sometimes in a beautiful and complex pattern.

Still not sure what he meant.
Does anybody know?

jeanna

?
the rate of changes of the current = the frequency.

but he is probably talking about modulating a frequency.
i could be wrong tho.

there are 2 kinds of modulations.
-Amplitude Modulation of a frequency.(AM radio)
-Frequency Modulation.(FM radio)

a mixe of both is also possible.
but, to my knowledge, this method is not used.
except perhap in some obscure, to me, audio frequencies mixers.

[Artic_Knight]

as i am no tesla i can only venture to guess at that comment but lets look at something. we were talking about "resonance" previously and what if we could find the resonance of frequency modulation?  imagine making a curcuit that used its frequency created to create a higher frequency? it would constantly climb! that would be interesting to study!

what about a "warble" basically as AC has a sinewave so would the frequency.  what if we could control the speed of a frequency by the ac sinewave? it would go up and down at a preset range IE 1khz to 4khz and back. it would gradually climb and decend. altho it would do it too fast for us to notice perse but it would do it at a gradual rate same as AC.  im not sophisticated enough with electronics to begin to compile such a curcuit but im sure one could be done that would use ac to both power and control the frequencies.

on a side note i played around with the earth batteries again and got a .8v at 3mah current but alas it was not enough for my basic JT. the voltage is fine but the amps just didnt come fast enough.  it was fun to charge some caps off the earth tho.

wasnt there a curcuit that was posted to run off 3mah? 

[jeanna]

...

on a side note i played around with the earth batteries again and got a .8v at 3mah current but alas it was not enough for my basic JT. the voltage is fine but the amps just didnt come fast enough.  it was fun to charge some caps off the earth tho.

wasnt there a curcuit that was posted to run off 3mah?

First thanks to you and theNOP for trying to answer this. I was just looking for it. Of course of all the things I kept open, this one I closed, so I will have to defer til later for the quote, which should have been there.

About the EB.

Put a cap in parallel with the battery leads.
If it is big enough you will get it to work. (I have not set it up for myself, so I should be less definitive...)
The thing is the larger the cap, the longer it will take to charge up and when the jt withdraws the power, it will be left empty. If it is too small, of course it won't do it.
So, I would say keep going up til it lights and stays lit.
Bill used a 1Farad supercap on his EB to light a plain led last year. So, that should be the best place to start. Go smaller if it cuts out to recharge, I think.

But remember the cap is attached to both battery leads for this to work.

jeanna
=======
OK this is too cool.
Maybe this is well known and a waste of everyone's time. I have never actually read the reference that explained the derivation of the term tank circuit.

I think I found it
I call it
"Why it is called a tank circuit..."
so, here it is in Tesla's words:

"by comparing the electrical
process with its mechanical analogue. The process may be illus-
trated in this manner. Imagine a tank with a wide opening at
the bottom, which is kept closed by spring pressure, but so that
it snaps off suddenly when the liquid in the tank has reached a
certain height. Let the fluid be supplied to the tank by means
of a pipe feeding at a certain rate. When the critical height of
the liquid is reached, the spring gives way and the bottom of the
tank drops out. Instantly the liquid falls through the wide open-
ing, and the spring, reasserting itself, closes the bottom again.
The tank is now filled, and after a certain time interval the same
process is repeated. It is clear, that if the pipe feeds the fluid
quicker than the bottom outlet is capable of letting it pass
through, the bottom will remain off. and the tank will still overflow.
If the rates of supply are exactly equal, then the bottom lid will
remain partially open and no vibration of the same" and of the
liquid column will generally occur, though it might, if started by
some means.
   But if the inlet pipe does not feed the fluid fast
enough for the outlet, then there will be always vibration.
Again, in such case, each time the bottom flaps up or down, the
spring and the liquid column, if the pliability of the spring and
the inertia of the moving parts are properly chosen, will perform
independent vibrations. In this analogue the fluid may be lik-
ened to electricity or electrical energy, the tank to the condenser,
the spring to the dielectric, and the pipe to the conductor through
which electricity is supplied to the condenser. To make this
analogy quite complete it is necessary to make the assumption,
that the bottom, each time it gives way, is knocked violently
against a non-elastic stop, this impact involving some loss of en-
ergy ; and that, besides, some dissipation of energy results due to
frictional losses. In the preceding analogue the liquid is sup-
posed to be under a steady pressure. If the presence of the fluid
be assumed to vary rhythmically, this may be taken as corres-
ponding to the case of an alternating current. The process is
then not quite as simple to consider, but the action is the same in
principle. It is desirable, in order to maintain the vibration
economically, to reduce the impact and frictional losses
as much as possible."
===