resistance heating, and the specific requirements are different.

If the electric heater adopts direct resistance heating, then the power supply voltage can be directly applied to the object to be heated. When current flows through, the object to be heated can generate heat. From this point of view, the object that can be directly heated by resistance must be a conductor, and it must have a higher resistivity. Since the heat is generated by the object itself, the thermal efficiency is bound to be high.