just the current-temperature chart. all resistance wire works that way. it's part of the reason our rbas work the way they do
just the current-temperature chart. all resistance wire works that way. it's part of the reason our rbas work the way they do
I think this is getting circular. The chart takes into account and is calculated based on heat transfer to quiet air. Quiet air is not a great conductor of heat. Quiet air does not have a relevant boiling point and will not act to limit the temperature of a coil heating in it. I take it you are saying that none of that is relevant? If so, then we do disagree.
The only reason I keep asking about this is just trying to conceptualize and predict what will make a wick coil assembly do what I want it to do without a huge amount of experimentation. I guess the experimentation is unavoidable lol.
As I mentioned in my first post about this, heat transfer between the wick and coil is part of the vapor production equation. But the fact that it takes less current to heat up a smaller wire is basic electronics. That's what we're discussing here.
As for experimentation, you will of course have to do some but understanding the effect of different variables is key to directing that experimentation.
The heat transfer and boiling point limitation is not relevant to the general concept of the relationship between wire size, temperature and current. If you are hung up on my use of "temperature" per se, consider "heat energy" instead perhaps. The temperature numbers in air are just a reflection of the increasing amount, illustrative for these purposes. In the end what causes a burnt hit usually is the drying out of the wick and the inability of it to replenish due to the increasing temperature of the coil. Smaller, hotter coils obviously will reach this point in a different way than wider coils.
Please see my edit, I clarified the issue a bit. To wit:
No a given wattage does not emit the same total heat energy. Note that there is no conservation between power in and heat out. Some of the power goes through the circuit. Heat is the "byproduct" of current flow and technically it is "wasted" power in the circuit. Conservation is between heat + the power that makes it through the wire.
Lower resistance technically means more efficiency, so less heat per watt. This is why low res coils kill batteries faster and why we have to pump up the power to get low res coils to produce.
From my understanding of electricity it is atoms pushing each other along a path. When that path is reduced they are pushing on each other with more force to get through that path which in turn creates heat. So the smaller path from higher gauge wire creates more heat.
That is basically a useful analogy but it is the electrons, not atoms. You are spot on that resistance will result in heat. One question bouncing around is will identical resistance result in identical heat at a fixed current, factoring out the resistors' abilities to transfer that heat away from themselves. So, will a, say, 1 ohm coil made of 30AWG wire generate more total heat than a 1 ohm coil made of 32AWG wire at a fixed voltage and thus fixed current (and obviously the 30AWG coil will be longer). I say same total heat output. The thinner wire may get to a hotter temperature because it can't transfer it's heat away from itself as efficiently as the thicker, and clearly the shorter, thinner wire coil has much less surface area, but energy is energy and the total heat energy should be the same.
So it makes maybe more sense, by total heat energy what I'm getting at is that if you placed each of the hypothetical coils in separate, say, 5cc volumes of water, the temperature rise over time in each little tub of water would be identical.
I do have a question....
So I am reading this bulk of knowledge and I think even if off topic this is a wonderful discussion, My question is regarding something I have done in the stereo market or have come to wonder and maybe this will answer those questions and some on the vape side.
If I wire a coil be it for a sub woofer or for a RBA and it is say 1 ohm as opposed to a 4 ohm setup, am I correct in assuming that because I lowered the ohms it is more efficent? If it is then when I wire a set of 15in subs to 1ohm as opposed to say 4 ohms My amp is working much harder but yet it is more efficently using the power so thats why it does not get as hot as say running at 4 ohms(contrary to what most beleave) it also means my subs are not getting as hot because again using that current more efficently correct? So if what I am saying is persumably correct does that mean that running lower ohms on a RBA is more stable on a thermal aspect? DOes that mean it should last longer and be a better coil than a 3 ohm set up theoretically? Am I headed in right direction and can someone that has more knowledge on this subject help to understand this enigma? dont mind my horrible spelling please, THanks in advance. Strapped
Same total heat output, yes, however the volume and surface area of the 32AWG coil will be far smaller than the 30AWG, so the heat emitted per size unit of that coil will be higher. That is not the result of heat transfer, that is inherent to electrical physics. Heat transfer considerations come after that. ...
If you ignore heat transfer as to "come after that," the basic electrical physics of increasing the temperature of a wire, any wire, is (I^2)R or more specifically, Q=(I^2)R, i.e., Joule's First Law. Not to be flip, but what basic electrical physics are you on about? Once we move on to heat per unit of area, we have to consider heat transfer. Ignoring heat transfer would have any current carrying wire tend toward infinite temperature over time. We know that's not what happens.
"Once we move on to heat per unit of area, we have to consider heat transfer." Yes, after the basic fact of more heat per unit of area.
I don't know what's hanging you up. Same amount of heat, much smaller surface. To think that would not be consequential fails even common sense.
The wire itself is emitting a higher heat intensity (heat per area unit) from its surface if it is smaller. Before ANY heat transfer considerations. Heat transfer may actually mask that, that could be where you are getting hung up.
Submerging the coils in the same volume of liquid effectively normalizes the volume/surface area. But that's not what happens in our atomizers unless maybe they are flooded, which is not how they work.