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On Jul 6, 12:26*am, Keith Dysart wrote:
On Jul 5, 8:33*am, Cecil Moore wrote: On Jul 4, 8:08*pm, Keith Dysart wrote: The system I have in mind has ports through which energy can flow in or out of the system and components inside the system which can store energy. For such a system, the energy flowing in to ports of the system minus the energy flowing out of ports *must equal the increase in energy being stored in the system. This must be true at all times, or energy is being created or destroyed; a bit of a no-no. But you are not tracking energy - you are tracking power. As Roy has said, there is no requirement that instantaneous power must balance. Where are the stored energy terms in any of your instantaneous power equations? How do you handle the difference in dimensions between energy and power? The only condition for which NET power must balance is during a time interval in which there is zero NET stored power, e.g. during one cycle. I have rev'ed my zero interference article to include the following statement: "Over a time period of many cycles, e.g. one second at MHz frequencies, the net average energy and the net average power are related by joules/second. Thus, if certain conditions are met, net average power can be used to track the net average energy flow based on the conservation of energy principle. However, at time intervals of less than one cycle, as exists for instantaneous power, power cannot be used to track energy because energy is often stored in a reactance, is not moving at that instant, and is therefore technically not power. In fact, unlike energy, power often appears and disappears. There are special cases where average power in joules/second can be used to track average energy in joules but instantaneous power is not one of those special cases." -- 73, Cecil, w5dxp.com Well, you are digging your hole deeper and deeper. You really should take a pause and try to understand the significance of "Continuity equations". Do seriously consider Kerchoff's current law as an example. ...Keith do you not think that it is telling that there is a current law and a voltage law, but not a basic power law included in basic circuit theory? maybe there is a reason for that. |
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