# Yihi SX350J 120W temperature controlled circuit



## Alex (21/1/15)

http://www.reddit.com/r/electronic_...ihi_sx350j_120w_temperature_controlled_chips/

Reactions: Like 8 | Informative 1


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## andro (21/1/15)

do you know if would work with nickel or kantal?


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## Alex (21/1/15)

andro said:


> do you know if would work with nickel or kantal?



I'll be sure to find out more, soon as I get to a pc.



Message sent via tapatalk

Reactions: Thanks 1


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## johan (21/1/15)

Can't see anything other than Nickel for proper temperature control.


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## Mike (21/1/15)

Supposedly it's either a nickel or titanium based wire...


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## JakesSA (21/1/15)

Mmm .. I have Nickel Titanium alloy wire here ..


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## andro (21/1/15)

johan said:


> Can't see anything other than Nickel for proper temperature control.


Why kanthal cant do it even on the evolve board ? ( only if is a short answer) in a way im not asking you to spend one hour typing .....


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## JakesSA (21/1/15)

Nickel changes its resistance at known values at different temperatures, Kanthal does not, or not reliably so, or not measurably so ..

Reactions: Like 1 | Agree 1 | Thanks 1 | Informative 3


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## JakesSA (21/1/15)

Kanthal is also an alloy which, I suspect, may have differing amounts of its constituent metals depending on where and even when it was manufactured. So even if you could get a reliable reading it may be different on the next batch of Kanthal you purchase. The Resistance vs Temperature change curve of Nickel is well documented and preprogrammed into the micro controller. Quite neat considering the micro controller needs the resistance to calculate required voltage anyway.

Keep in mind this change in resistance for Nickel is very small, 6.41 x 10^-3 per one degree Celcius.

Reactions: Thanks 1 | Informative 2


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## andro (21/1/15)

JakesSA said:


> Kanthal is also an alloy which, I suspect, may have differing amounts of its constituent metals depending on where and even when it was manufactured. So even if you could get a reliable reading it may be different on the next batch of Kanthal you purchase. The Resistance vs Temperature change curve of Nickel is well documented and preprogrammed into the micro controller. Quite neat considering the micro controller needs the resistance to calculate required voltage anyway.
> 
> Keep in mind this change in resistance for Nickel is very small, 6.41 x 10^-3 per one degree Celcius.


So thats why they suggest to keep the nickel between 0.13 and 0.20 ohm ? Correct?

Reactions: Agree 1


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## johan (21/1/15)

andro said:


> Why kanthal cant do it even on the evolve board ? ( only if is a short answer) in a way im not asking you to spend one hour typing .....



Exactly as @JakesSA described - you want the minimum resistance for temperature measurement.

Reactions: Thanks 1


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## JakesSA (21/1/15)

BTW, the YiHi website does not mention exactly how their temperature control is supposed to work...


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## Silver (21/1/15)

@JakesSA , thanks for the informative posts


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## JakesSA (21/1/15)

Thanks to @johan who initially pointed this out to me, he'll make an apprentice out of me yet!

Reactions: Funny 1


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## Alex (29/1/15)

http://www.reddit.com/r/electronic_..._sxmini_with_built_in_temperature_control_it/


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## Arthster (29/1/15)

To be honest, The temp control reliance on nickle confuses me as well. my understanding is that any conductor (even semi conductors) are temperature dependent. In other words, any conductive materiel has resistance fluctuations depending on the current working temperature (This includes copper conductors). This is one of the reasons a over heating PC becomes slower and slower until it bogs out. Resistance at temperature was how the first attempt at shutdown on Over heat worked. I might be wrong but maybe they just used nickle to build the algorithm on the software and that is the reason it wont run with Kanthol? Or am I just over thinking things, I do that sometimes

Reactions: Like 2


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## WHeunis (29/1/15)

Arthster said:


> To be honest, The temp control reliance on nickle confuses me as well. my understanding is that any conductor (even semi conductors) are temperature dependent. In other words, any conductive materiel has resistance fluctuations depending on the current working temperature (This includes copper conductors). This is one of the reasons a over heating PC becomes slower and slower until it bogs out. Resistance at temperature was how the first attempt at shutdown on Over heat worked. I might be wrong but maybe they just used nickle to build the algorithm on the software and that is the reason it wont run with Kanthol? Or am I just over thinking things, I do that sometimes



Yes, all conductors change as heat is applied. You are not overthinking it.
The reason for Ni200, as I stated earlier, is that it is the ideal material for doing so.
Unlike other conductors (like kanthal, nichrome, etc), Ni200 is *EXTREMELY SENSITIVE* and changes its resistance *NOTICEABLY* and *PREDICTABLY *to even the smallest temperature changes.
Most other conductors do not have those characteristics.

The other suitable material for this purpose, if you're wondering, is Titanium.
Trust me, coils would be way too flippin expensive if they go that route!

Reactions: Agree 1 | Thanks 1 | Informative 1


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## Arthster (29/1/15)

Thanks, that makes perfect sense. 

I agree Titanium would be way to expensive... would look awesome rocking a set of Titanium coils though

Reactions: Agree 1


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## Mike (29/1/15)

Whatever the story is, this development has me really excited.

Reactions: Agree 1


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## JakesSA (29/1/15)

Nitinol ..


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## Paulie (29/1/15)

As i agree with some of the above statements its rumored to work with kanthal  just a thought.. but my guess is nickel wirrree..


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## Snape of Vape (29/1/15)



Reactions: Like 1


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## JakesSA (29/1/15)

Don't quite get the joule mode though, if watt = joules per second, is it just a different way of expressing power consumed?

The manufacturer's set (not recommended) retail price on the standard SX mini is $180 or thereabouts so it would be interesting to see what the J variant goes for.


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