Okay, so I found from Amazon a cheap PTC thermistor with a fan, just search "Zerodis PTC" and you find it from there. I see it has 3 terminals, also other PTC elements do. Since it's a semiconductor component I'm assuming some gate-drain-source type of stuff of FETs, with the middle terminal voltage basically setting up the operating point. Am I right or wrong? It's been a long while since I studied any electronics so if you can explain from basics what those 3 terminals roles actually are, since it ought to be a resistor (2 terminals) with positive thermal coefficient of resistance. So, between which terminals is it actually a resistor, and how do I (if anyhow) have to setup the "operating point".
Though, I've also seen some other similar 3 terminal thermistors and many seem to have the two outer terminals shunted to each other. Is that how I should indeed operate thermistors and simply apply voltage from the middle to two outsides, and why?