Are the temperature adjustment knobs on most high-power AC (infrared or radiant) heaters just standard potentiometers, the same that would be found in low-power DC devices? I'm asking about the knobs that go from "low" to "high", not ones that list a specific temperature (like "76F").
More information (in response to comments):
I haven't yet opened the actual heater I'm referring to (it's difficult), but coincidentally I chanced upon an already-opened radiant heater and took a picture of the back of the knob and the internals.
What do you think it is? Is it safe to assume that a similar device is controlling my 1,500 watt IR heater? It's difficult for me to open the 1,500 watt unit, otherwise I would have done so already.
(I tried to post links to the heaters, but it wouldn't let me because I don't have enough reputation).
UPDATE: I finally took apart the IR heater that I was originally referring to. Sorry it took so long. It wasn't easy.
Here is a picture:
I tested the resistance on the 2 contacts, and it starts at 260K at the lowest setting, ending at around 80ohms at the highest heat setting.
Best Answer
It's a potentiometer that adjusts the firing angle of an SCR.
An SCR can be used as an inexpensive controller for a heater, by adjusting the firing angle you are controlling how much power is delivered to the heating element. SCRs only work on half the cycle. To gain a bit of efficiency, but also complexity a triac can be used. It will work like an SCR, but on both the positive and negative cycle.