First, the name is a bit of a misnomer - 'temperature control (TC)' would more accurately be called 'temperature limiting.' It sets a maximum temperature for the vapor produced by your coil, usually well below the point at which your wicking material will burn. This is helpful not only in avoiding the dreaded 'dry hits,' but in preventing you from prematurely destroying increasingly expensive replaceable coils.

Basically, in addition to setting your power in watts or volts, you also set your maximum temperature in degrees Celsius or Fahrenheit. Your device will use the full power you've allowed it until you reach the peak temperature, then it'll dial back the power to keep your vape hovering right around whatever sweet spot you've chosen.

The earliest, and still most popular, form of TC is based on the use of wire with a high nickel content, usually Ni200. It's used because the resistance of the wire changes as it heats up, and your TC mod monitors this resistance change to know when it should kick in and start limiting power delivery to keep you from going over your set maximum temperature. Newer devices are also using titanium and stainless steel in TC mode, though because the change in resistance as these wires heat is lower, the mathematics involved in creating a chip that effectively limits temperature is a bit more complex.

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One thing to note - while you can vape stainless steel in power mode, nickel wire can release chemicals dangerous for inhalation when overheated. Because of this, you should NEVER vape an Ni200 coil in a non-TC mod, or in a TC mod set to power mode.

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As with anything vape-related, the temperature control experience allows for a high degree of customization. So you'll have to play with the settings a bit in order to find the experience that works best for you, be it a long cool draw or a shorter, warmer hit. Your temperature control mod will come with instructions for setting the base resistance, you'll want to do this with a cool coil that's freshly installed to establish a base reading for your device to use in regulating the temperature going forward. Re-set your resistance whenever you take the tank off your mod and reinstall it, or every few tanks of vape juice if you're using a top-fill tank - wire resistance does change a bit as coils age, and regularly refreshing your coils will give you the best possible temperature control experience over the life of your coil.