Why does an electrical circuit produce heat at the point of resistance, if there is any resistance somewhere in the circuit? With no resistance(which would be less than ANY resistance), there is no heat produced in the circuit.
and, why do log vapes generally run hotter with time, assuming no charring? Wood will reach very dry very quick with a heater in it, especially when it was dry to begin with.
and another. Why do the heaters increase in ohms(and stay there) once fired up for a period of time?
Although there is more current going through the resistor, for a given amount of power, the lower the resistance, the lower the voltage drop across it. It's not possible to expect a resistor or wire at close to zero Ohms to drop 12V across it. You would need to pump an incredible amount of current through it for this to occur, and probably destroy the component and/or the power supply in the process. Ohm's law again: Power (Watts) = Voltage squared / Resistance, so given a 12V supply, a resistor at 20 Ohms will dissipate 7.2W, which we all know.
At 10 Ohms, 14.4W
At 1 Ohm, 144W
At 0.1 Ohm, 1.44kW
At 0.01 Ohm, 14.4kW, etc.
At this point we are probably reaching the limit of the mains supply to a typical house.
The wires in a circuit, which are close to zero Ohms, will drop a negligible amount of voltage across them; instead it is the other components that perform work, such as resistors, motors, etc, that do this. You wouldn't make a circuit that is simply a short (ie almost zero Ohms). Well you can, but you know what happens when you try to do that...
To put it another way, if you built a vape with a 1 Ohm resistor in it, you would only need a power supply of about 2.7V for the required 7.2W of dissipation to get it up to temperature. The power supply would need to deliver about 2.7A however... not very practical.
Log vapes running hotter over time probably has more to do with the wood than anything electrical. From experiments I've done, I've noticed the wood shrinks when high heat has been applied over time, even though the wood was completely dry to begin with. This would increase the density of the wood, allowing heat to be conducted to the outside surface more easily, so it would feel hotter in the hand. The design of the CRZ should mostly eliminate this I would think.
It's a very interesting discovery you have made about the resistors increasing in resistance over time. I can only guess that this is due to stress, kind of like an elastic band that has been stretched too far and doesn't quite return to its original size. We are, after all, running these resistors well outside of the manufacturer's operating limits. They aren't really designed to be used as heating elements. I'm surprised at how robust they are.