I've been lucky it appears. At work I use an adapter producing 5 volts DC @ 1 A. Haven't burned out the 901 coil, but I get great vapor...
Amperage of atomizer coil
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I bet you do. Great vapor means you are pushing the limits. Please tell us if your atomizer holds up.
I am pushing to make the heater coil design workable by pushing juices that are heat stable and deposit-free. The heater coil is the simplest approach.
At least a piezo approach is there in the wings if we need it
The chinese invented most things
i don't exactly agree that great vapor means pushing the limits. Efficiency is more critical than raw power. especially if we dont want burnt tastes and early atomizer failure. Ok, let's say pushing the limits of efficiency. It is not just about using the highest power the atty can take; the juice flow needs to be able to keep up with that.
At least a piezo approach is there in the wings if we need it
The chinese invented most things
i don't exactly agree that great vapor means pushing the limits. Efficiency is more critical than raw power. especially if we dont want burnt tastes and early atomizer failure. Ok, let's say pushing the limits of efficiency. It is not just about using the highest power the atty can take; the juice flow needs to be able to keep up with that.
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I know nothing, I see nothing, I don't waterboard. Except as a sport. Okay, I don't know much about volts and amps, some combos seem to work, others don't. If waskel gets good vapes at 5 volts and 1 amp, then my fried atomizer was just a fluke. More power to the vape gods. And you, my friend, should piezo de mayo. And I mean that in the best way.
I am pushing to make the heater coil design workable by pushing juices that are heat stable and deposit-free. The heater coil is the simplest approach.
At least a piezo approach is there in the wings if we need it
The chinese invented most things
i don't exactly agree that great vapor means pushing the limits. Efficiency is more critical than raw power. especially if we dont want burnt tastes and early atomizer failure. Ok, let's say pushing the limits of efficiency. It is not just about using the highest power the atty can take; the juice flow needs to be able to keep up with that.
Oops, my mistake. It's not 5volts@1A.
...It's 5volts@1.5A...
Yeah, if I let it go more than 3 or 4 seconds it can get a little burnt tasting, but 1-2 seconds is fine. Not a rig for those long, relaxing drags.
...It's 5volts@1.5A...
Yeah, if I let it go more than 3 or 4 seconds it can get a little burnt tasting, but 1-2 seconds is fine. Not a rig for those long, relaxing drags.
A simple and fun experiment you can do is to take apart one of your dead atomizers and salvage the coil wire. Then attach your leads to it, put your meter to test ohms, and heat the wire with a cigarette lighter while watching the meter. The resistance will go smoothly up as you heat the wire, and go back down as it cools.
Nichrome wires have positive temperature coefficients so your results imply it is not made of nichrome. See Wire: Nichrome (tm) & Other Resistance Alloys - Tech Data and Resistivity - Wikipedia, the free encyclopedia . Thermocouples with small wires can be used to measure temperature. I used spot welded 0.2mm j-type thermocouple with tuned tip.
Can you give some figures for the resistance - when cold and what it goes up to while vaping (and perhaps also when it goes red-hot)?
mogur, I've seen a similar measured effect,
effective resistance reducing with increased current/temp.,
I thought it was odd at the time:
2.9 V = 0.69 A = 4.2 Ohm
4.2 V = 1.10 A = 3.8 Ohm
This was on a 901 coil as well.
Plain nichrome wire resistance should, as vslim stated,
go up with temp., not down.
Maybe there's something else going on here,
like a solder joint effect maybe?
effective resistance reducing with increased current/temp.,
I thought it was odd at the time:
2.9 V = 0.69 A = 4.2 Ohm
4.2 V = 1.10 A = 3.8 Ohm
This was on a 901 coil as well.
Plain nichrome wire resistance should, as vslim stated,
go up with temp., not down.
Maybe there's something else going on here,
like a solder joint effect maybe?
Also strangely, looking at the data that jigtg linked to,
& extracting just the relevent figures,
there seems to be an odd dip in the resistance increase:
0.01mm Nichrome(A) 80% Ni, 20% Cr = 133 ohms/metre
Is that a measurement error or a real effect ?
& extracting just the relevent figures,
there seems to be an odd dip in the resistance increase:
0.01mm Nichrome(A) 80% Ni, 20% Cr = 133 ohms/metre
Code:
Amps Temp % resistance
increase
0.00 20 0.0
0.30 205 2.0
0.41 315 3.3
0.50 427 4.8
0.59 538 6.3
0.68 649 5.8
0.78 760 5.1
0.88 871 5.2
0.98 982 5.6
1.09 1093 6.0Is that a measurement error or a real effect ?
My Janty Kissbox Atomizers die in 2 to 3 weeks and Jeff at Janty is telling me its a learning curve. I think thats Bull
Do you make atomizers to sell that last a long time?
You're trying to hard ;-) , it's messing up your calculations. Rock, as you up your voltage, it will definitely increase the current, but that's not measuring the resistance change of the nichrome - it's proving ohms law The more you up the VOLTAGE, the more current it will consume.
You need to do the experiment with constant current (like 1 amp) and log the voltage as the coil heats up from dead cold. That will tell you the difference in resistance of the coil from cold to hot.
Anyone else with less techy stuff on their workbench - just put a voltmeter on the plus and minus of a 5 or 6volt *500ma* power supply, a transformer based one (500ma because you need something a little underpowered to try this)
Attach the atomizer, and watch the voltage go from 3.2 volts and climb up to 4.5 volts (or something similar, depending on how crappy your transformer is)
That's ohms law from the other direction... the volts will climb because the transformer is only capable of a fixed amount of current, and the coil resistance is dropping as it gets hotter.
The more you up the VOLTAGE, the more current it will consume.You need to do the experiment with constant current (like 1 amp) and log the voltage as the coil heats up from dead cold. That will tell you the difference in resistance of the coil from cold to hot.
Anyone else with less techy stuff on their workbench - just put a voltmeter on the plus and minus of a 5 or 6volt *500ma* power supply, a transformer based one (500ma because you need something a little underpowered to try this)
Attach the atomizer, and watch the voltage go from 3.2 volts and climb up to 4.5 volts (or something similar, depending on how crappy your transformer is)
That's ohms law from the other direction... the volts will climb because the transformer is only capable of a fixed amount of current, and the coil resistance is dropping as it gets hotter.
Okay, I have some fun results to report--doing the little experiment of cooking wires with a lighter while measuring resistance. I was so amazed by what I was seeing that I did it over and over, and always got the same thing--
My 901 factory att wire--almost no change in resistance when heated to red heat. This wire seems to be nichrome.
Stainless steel wire--resistance almost but not quite doubled when heated to red heat, going from 3 ohms to 5 ohms.
Sooo- I was wrong to say that nichrome resistance goes up with temperature. It just doesn't. Stainless steel certainly does, a lot. At least, this gives us an easy test to determine what our att wires are made of. It also explains why a given mod like the Magnum works for some atomizers and burns out others-- if the coil is some brand of stainless, the coil will tend to be current limiting with a fixed voltage like our battery sources and less likely to burn out. If it is nichrome it is safe to assume that the current will double with twice the voltage. If it is stainless, the current will increase, but not nearly as much.
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I don't think you were wrong as such, it's just something odd is happening,
simple nichrome wire resistance should definately increase with temperature
maybe you could comment about this post ?
http://www.e-cigarette-forum.com/forum/atomizer-mods/15020-wicking-material-3.html#post268876
(possibly tungsten wire woudl give an even better current limitation)
simple nichrome wire resistance should definately increase with temperature
maybe you could comment about this post ?
http://www.e-cigarette-forum.com/forum/atomizer-mods/15020-wicking-material-3.html#post268876
(possibly tungsten wire woudl give an even better current limitation)
Nichrome wire's increase in resistance is very small so harder to measure. That's a pity because if if was more pronounced, it would be easy for the chip to know when to cut off the supply when the coil gets dry.
Nichrome should be able to handle red-hot. Exo even took a coil to white hot, although briefly.
Nichrome should be able to handle red-hot. Exo even took a coil to white hot, although briefly.
Got antsy this morning and tested my 901 atomizer. 3.9 ohms cold
3.10v / 0.81a = 3.83 ohms
3.98v / 1.02a = 3.90 ohms
[didn't try 5 volts, too chicken]
The ecig I first tested wasn't a 901. It was an RN4075, as I have learned recently. It has "SH xxxxx" stamped on the battery connector. The 901 threads and the RN4075 threads are close, but don't match. I can only half screw the two different model components together.
jigtg, you are probably right. Reportedly, the manufacturers of the RN4075 hopped up the coil to produce more vapor, at the expense of reduced coil life. The fact that the measurements today indicate almost no change in ohms vs. amps (and therefore temperature), it appears the standard 901 is nichrome. What the material in the RN4075 coil is, I don't know. But, as you pointed out, it has a negative temperature coefficient, and a fairly significant one at that. I did measure its diameter as .004" (38ga), with a length about 1.3". Later disassembly showed that it wasn't wound evenly on its woven wick core, but rather bunched up in the middle of the core. What that all means is beyond me.
This is just what would be expected with nichrome - a slight increase in resistance with temperature. Very roughly, the temp would follow the power applied, IxIxR; so the second time the temp would be (at most, as heat loss rises with temp too) about 40% higher, yet the resistance less than 2%.
Thanks for reporting mogur
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