I'm actually trying to build a vape pen and the only problem i have right now is how i should limit the current going to the coil. Basically, if i had an 18650 battery hooked up to the coil through a button i would need some sort of device that can limit current so if i hold the button the coil doesn't melt/catch on fire. What circuit would i need to achive my goal?
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Limiting current on a mod
- Thread starter Hascct
- Start date
Mosfet.
None. Sounds like you are building a mechanical device. Battery, switch, coil and looking for a device to limit current. The main problem is, the current from a low resistance coil would most likely cook your mosfet. Generally, Mosfets are used to regulate current to a steady state, like 4.2V. Now since we judge how low our battery power level is by vapor production, you could end up with a dangerously low voltage battery state. The lower the voltage the harder your battery has to work to maintain a 4.2 V current.
So generally speaking, what you need is to use ohms law to calculate how many watts are applied across your heating coils.
example... 3.7V at 0.30 ohm resistance produces 40 watts
3.7V at 0.10 ohm resistance produces 136 watts
Using http://www.steam-engine.org/coil.html you can preplan your coil build to calculate how many watts produce how much heat. (heat flux)
Now of course, if you are building a regulated vape pen, the IC circuits handle this for you.
So generally speaking, what you need is to use ohms law to calculate how many watts are applied across your heating coils.
example... 3.7V at 0.30 ohm resistance produces 40 watts
3.7V at 0.10 ohm resistance produces 136 watts
Using http://www.steam-engine.org/coil.html you can preplan your coil build to calculate how many watts produce how much heat. (heat flux)
Now of course, if you are building a regulated vape pen, the IC circuits handle this for you.