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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?

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  • \$\begingroup\$ Searching for "Zerodis PTC" gets me a bunch of heating elements. Link to the part you mean. Preferably, link to the datasheet of the part you mean. If you can't find a datasheet, well, there's your problem. \$\endgroup\$
    – JRE
    Commented Jan 31, 2019 at 8:37
  • \$\begingroup\$ that search does not work for me either. \$\endgroup\$ Commented Jan 31, 2019 at 8:50
  • \$\begingroup\$ This one:amazon.com/Constant-Temperature-Electric-Heating-Incubator/dp/… \$\endgroup\$
    – soulblast
    Commented Jan 31, 2019 at 9:28
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    \$\begingroup\$ That's a link to an Amazon catalogue page. "No datasheet? No sale!" \$\endgroup\$
    – Transistor
    Commented Jan 31, 2019 at 9:54
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    \$\begingroup\$ If you have the answer post it as answer. This is not a forum. It is a question and answer site. If you don't formally close up a question, it stays active forever. Answer it yourself since you figured it out, then accept the answer. As a new user, you might have to wait a day to accept the answer. \$\endgroup\$
    – JRE
    Commented Jan 31, 2019 at 13:14

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Okay, I figured it out. Nothing magical in that. Each terminal is just simply connected to each aluminium heat sink, and it's all down to user to decide whether to run the resistors parallel or series, or if element has more than two resistors (3 heat sinks) in whatever pattern. Just stick to the rated voltage for each resistor (formed by the insulator between the heat sinks) and you're fine. PTC is even self regulating in limiting current and heat generation at higher temperatures so no overheating should occur even if fan were of lower speed.

I'll check through these kinda small PTC heat elements and order whichever I get easiest.

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