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Old 08-28-2009, 06:54 AM
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Harvey Harvey is offline
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Aaron, do you have any temp reading data that can be sync'd to the A column in a CSV? Even if it is just two or 3 readings as long as we can associate the time frame with the waveform analysis and temperature readings.

.99 probably got a little confused regarding the use of the word ambient. Thermodynamic laws dictate that everything must absorb or radiate energy in order to match ambient. The only way the resistors would be lower than ambient is if there has been a change either in the ambient or in the previously thermally neutral (ambient matched) temperatures. Wind chill for instance, can reduce the temperature of an object below ambient. Thermal hysteresis and state change can also cause temperature differentials between ambient and a object immersed in the ambient. But in this case, the loads and shunts should all have started at ambient.

As regards the noted cooling, there are a couple of things that can lead to this. RF is the most likely culprit for both the negative power results and the cooling. If you note my KCL comment, I qualified it by stating the 'wired' path. There is still a wireless path for the energy to flow and this is a difficult concept for some to grasp. Wireless power transmission is conventionally thought of as an exchange of voltage for transmitted power. In other words, at the end of the circuit, the current is the same but the voltage is spent to zero. But this does not have to be the case. We can conserve the voltage and spend the current instead. Very unconventional, but the result is some screwed up power readings when we base them on current in one leg of the circuit and it totally pisses all over KCL. But every well trained engineer knows that he can black box a transformer and end up with a current to voltage converter. This is one of the reasons a professor at MIT adamantly stressed the importance of using Faraday's laws instead of Kirchhoff's laws where dynamic fields are concerned. Kirchhoff's law is a subset of Faraday's law, which always works because it allows for path dependent analysis. When the system has an open door, as is the case with certain current consuming devices like RF power output, the path becomes important to the overall calculations. Those that grasp this concept will go far with future technology. Those that readily dismiss it will miss out on opportunities to explore seldom applied variations to the conventional application of electrodynamics.

However you accomplish it, it the total energy that leaves the load is more than the energy dumped into the load, the load must supply the energy either from itself or the pool of energy it contains in the form of temperature. In our case it is conventionally unlikely that the resistor is oxidizing or being consumed in some other fashion that results in a consistent holding of a temperature less than ambient. Especially if power is being dissipated in it. Therefore it is probable that it gives up it's thermal equilibrium in order to satisfy the energy exchange. This is nothing new. Einstein had few patents to his name but this is one he evidently felt strongly about: Using Heat to Refrigerate This type of cooling system is well known in the RV industry where almost all refrigeration systems work off of a heat principle and have no compressor. It is possible that your frequencies and arrangement do provide a release of extra energy from the resistor. Using RF to cool things

Well, back to my 555 stuff

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