I'm planning to buy a PTC ceramic heating element like the one shown here.
I wanted to know how to adjust the output temperature of such an element within the given output temperature range?
I'm fine with regulating the input voltage or current if that can change the output temperature.

  • 1
    \$\begingroup\$ Why would you buy this thing if it doesn't have a data sheet, and is supplied by amazon (zero provenance) and currently has no reviews? What would attract you to buy this thing? \$\endgroup\$
    – Andy aka
    May 13 '20 at 11:41
  • \$\begingroup\$ @Andyaka I could buy a similar one from other sites that have provided a data sheet or buy it at an offline store. This one is just an example. I've edited the question. \$\endgroup\$
    – Somanna
    May 13 '20 at 12:16
  • \$\begingroup\$ So, how will you know how to adjust the temperature of the one (the same one) that is linked in your question? How will you uncover the rules to do this? Can you find the techy information on that site you linked? \$\endgroup\$
    – Andy aka
    May 13 '20 at 12:31

The whole point of a PTC heating element is that it's PTC, Positive Temperature Coefficient.

As the element heats up, the resistance increases, usually sharply at the target temperature, reducing the current and so heat generated, when operated from a constant voltage supply. It automatically controls itself to its inbuilt transition temperature. As a result, these make very safe heaters, as if the heatsink fails, they stop dissipating automatically. The particular one you linked to specifies 180+/-10, though it's not clear whether that's C or F.

There are two main applications for which you would specify a PTC heater. One, where you want it to automatically control its own temperature at its transition temperature in normal service. Two, where you are controlling the temperature below that, but want a self-acting temperature limit should the controller fail.

You could control the temperature below the transition temperature by using a temperature sensor to feedback and limit the drive voltage. If you knew the resistance/temperature curve of the device, either from a specification or from measurement, you could use that as the sensor, with a little complication in multiplexing it for heat or sense duty.

  • \$\begingroup\$ So by varying the input (drive) voltage I can vary the output temperature? \$\endgroup\$
    – Somanna
    May 13 '20 at 13:11
  • \$\begingroup\$ By varying the drive power, you can vary the heat produced. Obviously the resistance depends on temperature, so varying the drive voltage will not necessarily get you what you want. Depending on what your thermal load is doing, that may or may not vary the temperature. \$\endgroup\$
    – Neil_UK
    May 13 '20 at 13:19

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