The resistance of the PTC tape is not DIRECTLY voltage dependent, but it is very strongly temperature dependent. At a lower line voltage, the input wattage would drop slightly, and this would reduce the temperature. This SLIGHTLY lower temperature will significantly reduce the resistance, and significantly increase the current.
The PTC tape will therefore be APPROXIMATLY a constant wattage load at any reasonable voltage. An ALMOST constant wattage requires more current at a lower line voltage.
Experiment and observation beats argument, buy a small PTC heating element and take measurements at different voltages and at different temperatures.
The resistance of the PTC tape is not DIRECTLY voltage dependent, but it is very strongly temperature dependent. At a lower line voltage, the input wattage would drop slightly, and this would reduce the temperature. This SLIGHTLY lower temperature will significantly reduce the resistance, and significantly increase the current.
The PTC tape will therefore be APPROXIMATLY a constant wattage load at any reasonable voltage. An ALMOST constant wattage requires more current at a lower line voltage.
Experiment and observation beats argument, buy a small PTC heating element and take measurements at different voltages and at different temperatures.
