Body
"Remember when Tesla demonstrated extracting energy at the nodal points
on a copper bar conductor??"
With the return path of the current it is a transmission line or a one turn coil. Thinking in DC circuits a copper bar is a short after the initial transient pulse or just a good conductor having almost the same tension all along its length. In AC circuits of high frequency or in pulsed DC circuits of high frequency the waves are shorter than the length of the copper bar as the velocity of the waves prevents a pulse or wave to reach the opposite end before the next pulse or wave is transmitted.
Source: https://en.wikisource.org/wiki/On_Light_and_Other_High_Frequency_Phenomena https://en.wikisource.org/wiki/On_Light_and_Other_High_Frequency_Phenomena
In the above figure of Tesla's experiment B and B' are the copper bars forming a transmission line. The reflections are different for shorted and open ends. A shorted end gives inverted voltage reflections while an open end gives inverted current reflections. When the load at the far end (top) is of the same impedance as that of the transmission line there will be no reflection from this end as all power reaching that far is then absorbed. The other loads can still reflect some of the signal if not impedance matched to the transmission line impedance.
An analysis on this experiment: https://waveguide.blog/brief-history-tesla-hairpin-circuit-stout-copper-bars/ https://waveguide.blog/brief-history-tesla-hairpin-circuit-stout-copper-bars/
Reflections on an open ended transmission line:
http://emlab.utep.edu/ee4347appliedem/TLStandingWave_open_logo.gif http://emlab.utep.edu/ee4347appliedem/TLStandingWave_open_logo.gif
Reflections on a shorted end transmission line:
http://emlab.utep.edu/ee4347appliedem/TLStandingWave_short_logo.gif http://emlab.utep.edu/ee4347appliedem/TLStandingWave_short_logo.gif
The green waves are the forward waves from the generator and the gray waves are the reflected waves. The red and blue standing waves are the resultant waves formed by superposition of the forward and reflected waves. By placing a load between the voltage and current notes power can be transferred to that load if it is of proper impedance as shown by Tesla.
For more animations of transmission lines go down to Topic 4 -- Transmission Lines here: http://emlab.utep.edu/ee4347appliedem.htm http://emlab.utep.edu/ee4347appliedem.htm
Regards
Ole
---In [email protected], <nwootan@...> wrote :
Remember when Tesla demonstrated extracting energy at the nodal points
on a copper bar conductor??
On 9/17/2011 2:44 PM, Jim Warren wrote:
> Norm
>
> ��� Do I have it thgether now?
>
> Jim