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Cecil Moore wrote:
John Popelish wrote: Cecil Moore wrote: If you want to deny the existence of forward and reflected current, be my guest. I deny it. There is only current at a point, just as there is only water jiggling around under a wave on the ocean. There is only water juggling under two or more waves in the ocean. Anyone who has stood on the beach has observed ocean waves moving in opposite directions. So waves can move in one or more directions while any bit of water moves only locally. Same with charge. Your assertion is easy to disprove. In the following example, the two sources have identical outputs and are phase locked. They are each equipped with circulators and 50 ohm loads. Source1---------------50 ohm coax------------------Source2 Got it. There is current flowing from Source1 heating up Source2's load resistor to the tune of I1^2*R. There is energy heating the load resistor. The current does not come through the source. It is created at the end of the line by the traveling energy wave. The charge that makes up the current passing back and forth through the load to produce the heat does not come from the source. It comes from the load itself and and the nearby part of the line (within less than a 1/2 wavelength). That charge is caused to move by the energy in the wave. There is current flowing from Source2 heating up Source1's load resistor to the tune of I2^2*R. No, for the same reason. The current is local to the end of the line near the load. It is not current that travels the length of the line from source to load, but the energy in the wave, just as the water from the underwater landslide is not what washes up on the beach a hundred miles away. Local water is pushed up on the beach by the energy in the traveling wave that connects the landslide with the beach. Your denial seems to be a denial of reality and more of a religious gut feeling than anything else. My denial is a recognition that current does not connect the source to the load, traveling energy waves do, however. Local current carries that wave along the line. If you disconnect Source2 completely in the example above the conditions will be the same except Source1 will be dissipating its own power after a round trip to the open end and back by the energy waves. Yes, its wave energy will return to the source and cause current local to the source to pass through that load. Incidentally, in the double source example above, which direction is the standing wave current flowing? At any point that is not a node, back and forth, every cycle. At nodes, back and forth across the dielectric of the line. How could its unchanging phase be used to measure the electrical length of the coax? You measure the difference of the node positions, with and without the coil. The shift in distance (in wavelengths) between the two nodes that straddle the coil is the phase shift of the coil for each of the traveling waves that make up the standing wave. |
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