Ok, I don't mean to sound condescending but this but this is really for folks that understand all of Ohm's law. There are 3 parts to impedance, capacitance, resistance and inductance. All I ever see discussed here is resistance which is really odd because we are dealing with coils (inductance) and resistance (Kanthal). I hear folks talk about the DC (or close to) voltage MVP's and Provari's put out, but it seems to me an AC signal like the other mods may be better. One advantage is the additional inductance would make the coil heat up before the legs preventing hot legs. I seriously doubt anyone can tell the difference between a coil heated by 33 HZ vice DC. It is getting pulsed 33 times a second. Your stove is driven at 60hz or 50 in EU. Personally, I think there's alot of hype going on. What do y'all think.
Ohm's law
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I think we focus on the safety aspect. I also think we focus on resistance with different gauges.
First off, there is no inductance in a coil used for vaping. That's only found with AC in Henry coils. A heating coil & a Henry coil are 2 completely different things. Impedance is only found in AC circuits & is basically the exact same thing as resistance (which is only found in DC circuits). Capacitance is also something that we're not dealing with. So the reason you don't see those 3 other terms are because they don't apply to vaping what so ever.
Regarding the PWM of regulated mods, you can either take a vape yourself & notice there's a huge difference between 33 & 800 cycles per second, or you can realize that a thermal coil on a stove isn't driven by direct household current & is not even a close comparison to how mods work.
Well....a coil is a coil. PWM is AC. There are expanding and collapsing magnetic fields. There is inductance in any coil and resistance affects AC and DC.
I think that given a particular PV (regardless of da chip or lack there of) one can toss out any capacitance and inductance; those become non-contributing factors while vaping on da same PV. Ergo, Ohm's law is quite valid when one is concerned 'bout their coil(s), batts and vaping safety.
Although, I guess we could get into an philosophical exercise of which is more relevant; eso or.teric...
Although, I guess we could get into an philosophical exercise of which is more relevant; eso or.teric...
From what I understand, PWM, while not flat DC, is not AC as the electrons are always flowing in one direction.
Incorrect.
PWM is not AC. It's nothing like AC. Even if our coils did have magnetic fields, it wouldn't matter for the purposes of vaping. But those fields are not there to begin with. Not every coil creates inductance and there is no such thing as resistance when dealing with AC. Just the same as there is no such thing as impedance when dealing with DC.
You're trying to apply advanced electronics situations that don't exist in basic vaping circuits where those things just simply do not exist.
I think that given a particular PV (regardless of da chip or lack there of) one can toss out any capacitance and inductance; those become non-contributing factors while vaping on da same PV. Ergo, Ohm's law is quite valid when one is concerned 'bout their coil(s), batts and vaping safety.
Although, I guess we could get into an philosophical exercise of which is more relevant; eso or.teric...
I agree capacitance is not a factor. Inductance is another matter. We are dealing with coils and in some instances, AC. I'd like to hear from an EE why inductance is not a factor. Maybe diameter vs frequency. Has anyone figure out the inductance of a 1.5 mm 8 wrap coil? Don't get to hung up on it. I'm sure some other (VERY FEW) have thought about it.
Every coil does create inductance, in an AC circuit. I've never put a scope on a mod to see what the actual sine wave looks like (next time I'm bored at work I may do this) but I doubt that they are putting out a clean wave. The fact that many mods are able to read voltages in average mode tells me that it is not a proper sine wave, as the average of a proper sine wave is always zero. This is why RMS is used, squaring the square root of the mean always gives you a positive value.
If you are curious as to how much inductance is present in your circuit, you will need an accurate ammeter and volt meter, and use the entire power formula which is:
P=IxExPF
where P= Power (watts) I = current (amps) E= voltage and PF = Power Factor.
Once you have calculated the power factor, you can use trig to calculate the inductive reactance, which I imagine will be a very tiny fraction of the circuit's overall impedance. This is pretty much an academic exersise, heating coils are generally considered unity devices, meaning a PF of zero.
If you are curious as to how much inductance is present in your circuit, you will need an accurate ammeter and volt meter, and use the entire power formula which is:
P=IxExPF
where P= Power (watts) I = current (amps) E= voltage and PF = Power Factor.
Once you have calculated the power factor, you can use trig to calculate the inductive reactance, which I imagine will be a very tiny fraction of the circuit's overall impedance. This is pretty much an academic exersise, heating coils are generally considered unity devices, meaning a PF of zero.
Everything you just posted is incorrect. This is basic electrical theory, nothing at all to do with electronics (which are entirely DC).
The circuit we use for vaping is pure DC - no different than hooking a switch and a resistor to a cell (which is exactly what we're doing). Regulated mods may alter that signal, but the output is still DC. PWM is still DC, not AC, which is a whole different ballgame. A Henry coil's potential for inductance is simply built on the fact that you're amplifying the magnetic field that forms around a conductor, coiled or not. However, in order for it to store energy in that magnetic field, it needs to retain that energy in the first place. A "resistive" wire such as Kanthal dissipates that energy in the form of heat so the magnetic field cannot be built up around the wire in the first place. If you coil up a wire that is dissipating it's energy in the form of heat, it can't multiply a field that isn't there. It can't store energy that's being released in another form.
Thank you. That was my point. It is not a clean sine wave but still a changing voltage. I was hoping someone had figured the impact based on the frequency and coil diameter. Inductance is part of the total impedance. It may not have an impact but i am curious if anyone has done the math.
PWM is AC. It is one of the most common outputs of inverters, UPS systems and variable frequency drives. If it wasn't, then mods would not be able to output voltages higher than whatever their battery charge happened to be, as DC cannot be transformed. Transformers require AC.
I'm not a coil expert, I don't know if this is correct. But when you post that there is no such thing as resistance in AC, or that PWM is not AC, I have to say something, because that's just incorrect.
While PWM in a PV is a rectangular wave and not flat DC, how can it be considered AC when electrons are always moving in the same direction? There's no alternating current.
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True...it is not actually alternating current however Increasing and deceasing current in a coil causes the magnetic field to change. Doesn't matter if it goes above and below 0 volts. A coil will resist the change.
DC can be transformed. Very easily. A transformer proper is changing AC-AC or AC-DC, but that doesn't mean you can't change the characteristics of DC. Pretty much every useful electronics system does it all the time. You use a transformer to regulate the incoming AC to DC & that DC current can be altered further depending on the sub-circuit. It's done all the time in amateur radio & isn't all that complex.
PWM is still not AC. It's a modulation of the input current. If the input current is DC, it doesn't magically change to AC. It's a filter, or more accurately the result from a filter.
Furthermore, no, there is no such thing as resistance in an AC circuit. There is impedance. There is no impedance in a DC circuit, there is resistance. They are in essence the same concept, but still not the same thing.
I understand there are a lot of so-called electronics/electrical "experts" that started vaping & figured out how to read an Ohms Law calculator & read a few webpages. Please don't confuse me with that group. I've been working with electronics for a couple of decades, electrical work for almost that long & learned Ohms Law & how this all works back when the public school system was worth a crap. I apologize if my responses came across terse. There were some kids on my lawn earlier today & didn't leave when I shook my cane at them. It was upsetting.
Obviously you learned electronics in a different world than I did. Most everything you said is incorrect, but then again, I've only been teaching and applying it in practical application for about 38 years. Don't want to pick it apart piece by piece. I hope I'm right, if not our Navy is in bad shape.
I would really like to hear from some with an EE that can address coil size and frequency as it relates to vaping.
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