How does a fan regulator ?

[barryforever]

Here is a silly doubt that crept in my mind...
Like how does a fan regulator work ?
is it like a potentiometer ?
can it control current delivered to the fan or does it control ac voltage

 

[sec]

what kind of fan ?
If you mean a PC fan there is a micro controller that drive a brushless motor.
If you talk about a big dc motor, search on google for triac variator

 

[barryforever]

well it goes to a heater i want to vary the heaters output ...
im unsure the regulator controls the voltage or current